Searching for Double Beta Decay with GERDA · [1] Eur. Phys. J. A12, 147-154 (2001) [2] Phys. Rev....
Transcript of Searching for Double Beta Decay with GERDA · [1] Eur. Phys. J. A12, 147-154 (2001) [2] Phys. Rev....
![Page 1: Searching for Double Beta Decay with GERDA · [1] Eur. Phys. J. A12, 147-154 (2001) [2] Phys. Rev. D 65, 092007 (2002) Claim of signal from parts of HdM: T 1/2 (76Ge) = (0.69 –](https://reader034.fdocuments.us/reader034/viewer/2022050212/5f5e4aaf5c00cd76d9057fc3/html5/thumbnails/1.jpg)
Searching for Double Beta Searching for Double Beta Decay with GERDADecay with GERDA
Sabine Hemmer for the GERDA collaboration
Universitagrave di Padova INFN Padova
Les Rencontres de Physique de la Valleacutee dAosteLes Rencontres de Physique de la Valleacutee dAosteLa Thuile 26 February ndash 3 March 2012La Thuile 26 February ndash 3 March 2012
Outline
Sabine Hemmer 27 February 2012 1
Neutrinoless double beta decay (0νββ)
The GERDA experiment
First data
Phase II preparations
Why do we search for 0νββ
Sabine Hemmer 27 February 2012 2
Unveil the nature of neutrinos
If 0νββ observed Neutrino is a Majorana particle (ν=ν) Lepton number violation ΔL=2 Sheds light on absolute neutrino mass scale Sheds light on neutrino mass hierarchy
Majoranaν=ν
Diracνneν
or
2νββ and 0νββ
Sabine Hemmer 3
n
n p
p
e-
e-
νν2νββ
n
n p
p
e-
e-
ν=ν0νββ
allowed by SM ΔL=0 observed in many isotopes T
12~1019-1021y
Forbidden process in SM needs Majorana neutrino
ΔL=2 (T
12)-1 = G0ν (Q
ββZ)middot |M0ν|2 middot ltm
ββgt2
G0ν (Qββ
Z) Phase space (~Qββ
5)
|M0ν|2 nuclear matrix elementltm
ββgt2=|sum
iU
ei2m
i|2
27 February 2012
Experimental signature
76Ge
Peak at Qββ
2νββ and 0νββ
Sabine Hemmer 427 February 2012
2νββ0νββ
n
n p
p
e-
e-
νν2νββ
n
n p
p
e-
e-
ν=ν0νββ
Searching in 76Ge
Advantages of Germanium
High ε Source = Detector Small instrinsic b High purity Ge Excellent ΔE FWHM ~ (01-02) Well-established technology
Disadvantages of Germanium
High external b Qββ
=2039keV
Small a of 76Ge 78 rarrEnrichment needed
Limited sources of crystal amp detector manufacturers
Sabine Hemmer 527 February 2012
Ssimϵsdotasdotradic MsdottbΔE
S sensitivityε efficiencya abundance of 2νββ isotopeM detector mass
t measured timeb background indexΔE detector resolution
Germanium detector
Previous 76Ge experiments
[1] Eur Phys J A12 147-154 (2001)[2] Phys Rev D 65 092007 (2002)
Claim of signal from parts of HdMT
12 (76Ge) = (069 ndash 418)middot1025y (3σ) (Phys Lett B 586 198-212 (2004))
Sabine Hemmer 627 February 2012
HdM IGEX
Location LNGSHomestake Baksan
Canfranc
Exposure [kgmiddoty] 711 89
Bg [countskeVmiddotkgmiddoty] 011 017
T12
limit (90 CL) [y] 19middot1025 [1] 16middot1025 [2]
GERDA physics goal
Ph
ys R
ev D
092
003
(200
6)
F F
eru
glio
A S
tru
mia
F V
issa
ni
NP
B 6
59
Phase IPhase II
18kg (HdMIGEX) enriched (~86) + 15kg natural reach background of 10-2 counts(keVmiddotkgmiddoty) Exposure of 15 kgmiddoty rarr check claim ltm
ββgt le (023-039) eV (Phys Rev C 81 (2010) 028502)
add ~20kg new enr detectors reach background of 10-3 counts(keVmiddotkgmiddoty) Exposure of 100kgmiddoty Trarr
12 gt 15middot1026y
ltmββ
gt le (009-015) eV (Phys Rev C 81 (2010) 028502)
Phase I
Phase II
Sabine Hemmer 727 February 2012
Phase I
Phase II
Background reduction
3400 mwe
Sabine Hemmer 827 February 2012
GERDA situtated in LNGS underground laboratories suppression of cosmic ray muons by factor 106 by overlaying rock
Graded shielding against ambient radiation Rigorous material selection Avoid exposure above ground for detectors
High-purity LAr (64m3) shield and coolant (Option active veto)
Phase I array
Clean room
Steel cryostat with internal copper shield
Ultrapure water (580m3) n moderator Cherenkov medium for μ veto
Lock
Background reduction
ββ
Ge
Multi-site energy deposition inside HP-Ge diode
(Compton scattering)
γγ βCo-60
Point-like (single-site) energy deposition inside one HP-Ge
diode (Range ~ 1mm)
Signal Background
Signal analysis anti-coincidence between detectors pulse shape analysis (PSA)
Sabine Hemmer 927 February 2012
Start of Phase I6 November 2011 Start of Phase I
All 8 enrGe + 4 natGe detectors deployed in GERDA(2 enrGe detectors presently not used for analysis)
natGe 197 kgmiddoty (76 kg)
enrGe 380 kgmiddoty (146 kg)
Sabine Hemmer 1027 February 2012
Energy spectrum
(Unexpected) Background from Argon
101 Bqkg T12
=269 y
pure β emitter Q-value=565keV rarr below region of interest
39Ar
Sabine Hemmer 1127 February 2012
42ArGERDA proposal 42ArnatAr lt 3 x 10-21 (Barabash et al 2002)GERDA measurement Count rate at 1525keV ~ 2 times expectation
Field-free configuration
Region of Interest
middot
Background rate in ROI (Qββ
plusmn100 keV blinded window excluded) enrGe 0017+0009
-0005 counts(keVmiddotkgmiddoty)
natGe 0049+0015-0013
counts(keVmiddotkgmiddoty) most likely a combination of ThU 42K degraded α cosmogenic isotopes factor ~10 lower than previous experiments (HdM IGEX) no pulse shape analysis applied yet
ROI
blinded
ROI
blinded
Sabine Hemmer 1227 February 2012
2νββ
middot
39Ar 101 Bqkg from WARP [NIM A574 83-88 (2007)]
76Ge T12
(2νββ)=174middot1021y from HdM
[NIM A513 596-621 (2003)]
42K homogeneously distributed decays in LAr (normalized to peak)
40K simulated decays in detector holders (normalized to peak)
Sum of MC contributionsData
Sabine Hemmer 1327 February 2012
Phase II detectorscu
rren
t
time [ns]
ββ decay
ACCEPT
γ ray background REJECT
REJECT42K β UTh chain αs
Peculiar pulses
0νββ-like
90 11
γ-bgd
A
A
Sabine Hemmer 1427 February 2012
BEGe production
Sabine Hemmer 1527 February 2012
Crystal pulling at Canberra Oakridge TN USA
BEGe detector diode production Olen BE
BEGe acceptance tests Hades BE
ONGOING ONGOING
ONGOING
First spectra
RampD liquid argon instrumentation
photons
Liquid argon
Detection of coincident liquid argon scintillation
light to discriminate background
LarGe Low-background test facility at LNGS
Sabine Hemmer 1627 February 2012
Also other designs investigated rarr avoid additional background
Combining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Summary
GERDA Phase I started in November 2011 Unexpectedly high contribution from 42Ar decays Background in ROI lower than in previous experiments (~ factor 10)
but slightly higher than design goal 2νββ spectrum well reproduced by MC (taking into account
contributions from 39Ar 42Ar and 40K) Phase II detector production and RampD on LAr scintillation light
readout ongoing
Sabine Hemmer 1727 February 2012
The GERDA collaboration
Sabine Hemmer 1827 February 2012
BackupHdM claim
Nov 1990 - May 2003 717 kg year Bgd 011 counts (keVkgy) 2875 plusmn 687 events (bgd~60) 42σ evidence for 0νββ
(069 ndash 418)middot1025 y (3 σ) Best fit 119middot1025 y
mββ
= (024-058) eV
best fit 044 eV
Note statistical significance depends on background model
Phys Lett B 586 198-212 (2004)
Comparison IGEX
D Gonzalez et al NPB (Proc Suppl) 87 (2000) 278
Sabine Hemmer B127 February 2012
Backup α events
Sabine Hemmer B227 February 2012
Backup calibration
Sabine Hemmer B327 February 2012
BackupNeutrino properties
What we know m
22-m
12=Δm
sun2
m2
2-m1
2=Δmatm
2
θ12
=θsun
θ23
=θatm
θ
13
What we do not know Absolute mass scale Mass hierarchy Phases (δ
13 α
21 α
31)
Nature of the neutrino mass (Dirac or Majorana)
Sabine Hemmer B427 February 2012
Shockley-Ramo TheoremQ(t)=-qmiddotΦ
w(r(t))
BackupPhase II detectors
Ew(r)=-nablaΦ
Sabine Hemmer B527 February 2012
Backup Background reduction
Key issue Low background rate (Phase I 110 HdM)
sensitivitysimϵsdotasdotradic MsdottbΔ E
Possible backgrounds External
γ from Th and U chain neutrons from spallation μ from cosmic rays
Internal cosmogenic 60Co (T
12=53y)
cosmogenic 68Ge (T12
=271d)
Radioactive surface contamination
Sabine Hemmer B627 February 2012
before MS (059 kgy)
after MS (037 kgy)
Backup Play with the electric fieldAdd a mini-shroud (MS)
70 cm
Shroud (already installed to prevent 222Rn concentration)
+ +- -+ +- -
MSV
S-MS=+700V (019 kgy)
VS-MS
=-400V (037 kgy)
Sabine Hemmer B727 February 2012
Backup Muon induced events
dataMC
Spectrum of muon-induced events in Germanium (209 kgy during commissioning)
Estimate of muon veto efficiency for events causing a signal in Ge ε = 987Estimate of muon-induced background at Q
ββ B
μ lt 20middot10-4 countskeVmiddotkgmiddoty
middot
Sabine Hemmer B827 February 2012
Operation of Phase II proto-type detector in LarGeCombining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Also successful read out scintillation light with fibers coupled to SiPMs
Sabine Hemmer B927 February 2012
Backup RampD liquid argon instrumentation
- Pagina 1
- Pagina 2
- Pagina 3
- Pagina 4
- Pagina 5
- Pagina 6
- Pagina 7
- Pagina 8
- Pagina 9
- Pagina 10
- Pagina 11
- Pagina 12
- Pagina 13
- Pagina 14
- Pagina 15
- Pagina 16
- Pagina 17
- Pagina 18
- Pagina 19
- Pagina 20
- Pagina 21
- Pagina 22
- Pagina 23
- Pagina 24
- Pagina 25
- Pagina 26
- Pagina 27
- Pagina 28
-
![Page 2: Searching for Double Beta Decay with GERDA · [1] Eur. Phys. J. A12, 147-154 (2001) [2] Phys. Rev. D 65, 092007 (2002) Claim of signal from parts of HdM: T 1/2 (76Ge) = (0.69 –](https://reader034.fdocuments.us/reader034/viewer/2022050212/5f5e4aaf5c00cd76d9057fc3/html5/thumbnails/2.jpg)
Outline
Sabine Hemmer 27 February 2012 1
Neutrinoless double beta decay (0νββ)
The GERDA experiment
First data
Phase II preparations
Why do we search for 0νββ
Sabine Hemmer 27 February 2012 2
Unveil the nature of neutrinos
If 0νββ observed Neutrino is a Majorana particle (ν=ν) Lepton number violation ΔL=2 Sheds light on absolute neutrino mass scale Sheds light on neutrino mass hierarchy
Majoranaν=ν
Diracνneν
or
2νββ and 0νββ
Sabine Hemmer 3
n
n p
p
e-
e-
νν2νββ
n
n p
p
e-
e-
ν=ν0νββ
allowed by SM ΔL=0 observed in many isotopes T
12~1019-1021y
Forbidden process in SM needs Majorana neutrino
ΔL=2 (T
12)-1 = G0ν (Q
ββZ)middot |M0ν|2 middot ltm
ββgt2
G0ν (Qββ
Z) Phase space (~Qββ
5)
|M0ν|2 nuclear matrix elementltm
ββgt2=|sum
iU
ei2m
i|2
27 February 2012
Experimental signature
76Ge
Peak at Qββ
2νββ and 0νββ
Sabine Hemmer 427 February 2012
2νββ0νββ
n
n p
p
e-
e-
νν2νββ
n
n p
p
e-
e-
ν=ν0νββ
Searching in 76Ge
Advantages of Germanium
High ε Source = Detector Small instrinsic b High purity Ge Excellent ΔE FWHM ~ (01-02) Well-established technology
Disadvantages of Germanium
High external b Qββ
=2039keV
Small a of 76Ge 78 rarrEnrichment needed
Limited sources of crystal amp detector manufacturers
Sabine Hemmer 527 February 2012
Ssimϵsdotasdotradic MsdottbΔE
S sensitivityε efficiencya abundance of 2νββ isotopeM detector mass
t measured timeb background indexΔE detector resolution
Germanium detector
Previous 76Ge experiments
[1] Eur Phys J A12 147-154 (2001)[2] Phys Rev D 65 092007 (2002)
Claim of signal from parts of HdMT
12 (76Ge) = (069 ndash 418)middot1025y (3σ) (Phys Lett B 586 198-212 (2004))
Sabine Hemmer 627 February 2012
HdM IGEX
Location LNGSHomestake Baksan
Canfranc
Exposure [kgmiddoty] 711 89
Bg [countskeVmiddotkgmiddoty] 011 017
T12
limit (90 CL) [y] 19middot1025 [1] 16middot1025 [2]
GERDA physics goal
Ph
ys R
ev D
092
003
(200
6)
F F
eru
glio
A S
tru
mia
F V
issa
ni
NP
B 6
59
Phase IPhase II
18kg (HdMIGEX) enriched (~86) + 15kg natural reach background of 10-2 counts(keVmiddotkgmiddoty) Exposure of 15 kgmiddoty rarr check claim ltm
ββgt le (023-039) eV (Phys Rev C 81 (2010) 028502)
add ~20kg new enr detectors reach background of 10-3 counts(keVmiddotkgmiddoty) Exposure of 100kgmiddoty Trarr
12 gt 15middot1026y
ltmββ
gt le (009-015) eV (Phys Rev C 81 (2010) 028502)
Phase I
Phase II
Sabine Hemmer 727 February 2012
Phase I
Phase II
Background reduction
3400 mwe
Sabine Hemmer 827 February 2012
GERDA situtated in LNGS underground laboratories suppression of cosmic ray muons by factor 106 by overlaying rock
Graded shielding against ambient radiation Rigorous material selection Avoid exposure above ground for detectors
High-purity LAr (64m3) shield and coolant (Option active veto)
Phase I array
Clean room
Steel cryostat with internal copper shield
Ultrapure water (580m3) n moderator Cherenkov medium for μ veto
Lock
Background reduction
ββ
Ge
Multi-site energy deposition inside HP-Ge diode
(Compton scattering)
γγ βCo-60
Point-like (single-site) energy deposition inside one HP-Ge
diode (Range ~ 1mm)
Signal Background
Signal analysis anti-coincidence between detectors pulse shape analysis (PSA)
Sabine Hemmer 927 February 2012
Start of Phase I6 November 2011 Start of Phase I
All 8 enrGe + 4 natGe detectors deployed in GERDA(2 enrGe detectors presently not used for analysis)
natGe 197 kgmiddoty (76 kg)
enrGe 380 kgmiddoty (146 kg)
Sabine Hemmer 1027 February 2012
Energy spectrum
(Unexpected) Background from Argon
101 Bqkg T12
=269 y
pure β emitter Q-value=565keV rarr below region of interest
39Ar
Sabine Hemmer 1127 February 2012
42ArGERDA proposal 42ArnatAr lt 3 x 10-21 (Barabash et al 2002)GERDA measurement Count rate at 1525keV ~ 2 times expectation
Field-free configuration
Region of Interest
middot
Background rate in ROI (Qββ
plusmn100 keV blinded window excluded) enrGe 0017+0009
-0005 counts(keVmiddotkgmiddoty)
natGe 0049+0015-0013
counts(keVmiddotkgmiddoty) most likely a combination of ThU 42K degraded α cosmogenic isotopes factor ~10 lower than previous experiments (HdM IGEX) no pulse shape analysis applied yet
ROI
blinded
ROI
blinded
Sabine Hemmer 1227 February 2012
2νββ
middot
39Ar 101 Bqkg from WARP [NIM A574 83-88 (2007)]
76Ge T12
(2νββ)=174middot1021y from HdM
[NIM A513 596-621 (2003)]
42K homogeneously distributed decays in LAr (normalized to peak)
40K simulated decays in detector holders (normalized to peak)
Sum of MC contributionsData
Sabine Hemmer 1327 February 2012
Phase II detectorscu
rren
t
time [ns]
ββ decay
ACCEPT
γ ray background REJECT
REJECT42K β UTh chain αs
Peculiar pulses
0νββ-like
90 11
γ-bgd
A
A
Sabine Hemmer 1427 February 2012
BEGe production
Sabine Hemmer 1527 February 2012
Crystal pulling at Canberra Oakridge TN USA
BEGe detector diode production Olen BE
BEGe acceptance tests Hades BE
ONGOING ONGOING
ONGOING
First spectra
RampD liquid argon instrumentation
photons
Liquid argon
Detection of coincident liquid argon scintillation
light to discriminate background
LarGe Low-background test facility at LNGS
Sabine Hemmer 1627 February 2012
Also other designs investigated rarr avoid additional background
Combining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Summary
GERDA Phase I started in November 2011 Unexpectedly high contribution from 42Ar decays Background in ROI lower than in previous experiments (~ factor 10)
but slightly higher than design goal 2νββ spectrum well reproduced by MC (taking into account
contributions from 39Ar 42Ar and 40K) Phase II detector production and RampD on LAr scintillation light
readout ongoing
Sabine Hemmer 1727 February 2012
The GERDA collaboration
Sabine Hemmer 1827 February 2012
BackupHdM claim
Nov 1990 - May 2003 717 kg year Bgd 011 counts (keVkgy) 2875 plusmn 687 events (bgd~60) 42σ evidence for 0νββ
(069 ndash 418)middot1025 y (3 σ) Best fit 119middot1025 y
mββ
= (024-058) eV
best fit 044 eV
Note statistical significance depends on background model
Phys Lett B 586 198-212 (2004)
Comparison IGEX
D Gonzalez et al NPB (Proc Suppl) 87 (2000) 278
Sabine Hemmer B127 February 2012
Backup α events
Sabine Hemmer B227 February 2012
Backup calibration
Sabine Hemmer B327 February 2012
BackupNeutrino properties
What we know m
22-m
12=Δm
sun2
m2
2-m1
2=Δmatm
2
θ12
=θsun
θ23
=θatm
θ
13
What we do not know Absolute mass scale Mass hierarchy Phases (δ
13 α
21 α
31)
Nature of the neutrino mass (Dirac or Majorana)
Sabine Hemmer B427 February 2012
Shockley-Ramo TheoremQ(t)=-qmiddotΦ
w(r(t))
BackupPhase II detectors
Ew(r)=-nablaΦ
Sabine Hemmer B527 February 2012
Backup Background reduction
Key issue Low background rate (Phase I 110 HdM)
sensitivitysimϵsdotasdotradic MsdottbΔ E
Possible backgrounds External
γ from Th and U chain neutrons from spallation μ from cosmic rays
Internal cosmogenic 60Co (T
12=53y)
cosmogenic 68Ge (T12
=271d)
Radioactive surface contamination
Sabine Hemmer B627 February 2012
before MS (059 kgy)
after MS (037 kgy)
Backup Play with the electric fieldAdd a mini-shroud (MS)
70 cm
Shroud (already installed to prevent 222Rn concentration)
+ +- -+ +- -
MSV
S-MS=+700V (019 kgy)
VS-MS
=-400V (037 kgy)
Sabine Hemmer B727 February 2012
Backup Muon induced events
dataMC
Spectrum of muon-induced events in Germanium (209 kgy during commissioning)
Estimate of muon veto efficiency for events causing a signal in Ge ε = 987Estimate of muon-induced background at Q
ββ B
μ lt 20middot10-4 countskeVmiddotkgmiddoty
middot
Sabine Hemmer B827 February 2012
Operation of Phase II proto-type detector in LarGeCombining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Also successful read out scintillation light with fibers coupled to SiPMs
Sabine Hemmer B927 February 2012
Backup RampD liquid argon instrumentation
- Pagina 1
- Pagina 2
- Pagina 3
- Pagina 4
- Pagina 5
- Pagina 6
- Pagina 7
- Pagina 8
- Pagina 9
- Pagina 10
- Pagina 11
- Pagina 12
- Pagina 13
- Pagina 14
- Pagina 15
- Pagina 16
- Pagina 17
- Pagina 18
- Pagina 19
- Pagina 20
- Pagina 21
- Pagina 22
- Pagina 23
- Pagina 24
- Pagina 25
- Pagina 26
- Pagina 27
- Pagina 28
-
![Page 3: Searching for Double Beta Decay with GERDA · [1] Eur. Phys. J. A12, 147-154 (2001) [2] Phys. Rev. D 65, 092007 (2002) Claim of signal from parts of HdM: T 1/2 (76Ge) = (0.69 –](https://reader034.fdocuments.us/reader034/viewer/2022050212/5f5e4aaf5c00cd76d9057fc3/html5/thumbnails/3.jpg)
Why do we search for 0νββ
Sabine Hemmer 27 February 2012 2
Unveil the nature of neutrinos
If 0νββ observed Neutrino is a Majorana particle (ν=ν) Lepton number violation ΔL=2 Sheds light on absolute neutrino mass scale Sheds light on neutrino mass hierarchy
Majoranaν=ν
Diracνneν
or
2νββ and 0νββ
Sabine Hemmer 3
n
n p
p
e-
e-
νν2νββ
n
n p
p
e-
e-
ν=ν0νββ
allowed by SM ΔL=0 observed in many isotopes T
12~1019-1021y
Forbidden process in SM needs Majorana neutrino
ΔL=2 (T
12)-1 = G0ν (Q
ββZ)middot |M0ν|2 middot ltm
ββgt2
G0ν (Qββ
Z) Phase space (~Qββ
5)
|M0ν|2 nuclear matrix elementltm
ββgt2=|sum
iU
ei2m
i|2
27 February 2012
Experimental signature
76Ge
Peak at Qββ
2νββ and 0νββ
Sabine Hemmer 427 February 2012
2νββ0νββ
n
n p
p
e-
e-
νν2νββ
n
n p
p
e-
e-
ν=ν0νββ
Searching in 76Ge
Advantages of Germanium
High ε Source = Detector Small instrinsic b High purity Ge Excellent ΔE FWHM ~ (01-02) Well-established technology
Disadvantages of Germanium
High external b Qββ
=2039keV
Small a of 76Ge 78 rarrEnrichment needed
Limited sources of crystal amp detector manufacturers
Sabine Hemmer 527 February 2012
Ssimϵsdotasdotradic MsdottbΔE
S sensitivityε efficiencya abundance of 2νββ isotopeM detector mass
t measured timeb background indexΔE detector resolution
Germanium detector
Previous 76Ge experiments
[1] Eur Phys J A12 147-154 (2001)[2] Phys Rev D 65 092007 (2002)
Claim of signal from parts of HdMT
12 (76Ge) = (069 ndash 418)middot1025y (3σ) (Phys Lett B 586 198-212 (2004))
Sabine Hemmer 627 February 2012
HdM IGEX
Location LNGSHomestake Baksan
Canfranc
Exposure [kgmiddoty] 711 89
Bg [countskeVmiddotkgmiddoty] 011 017
T12
limit (90 CL) [y] 19middot1025 [1] 16middot1025 [2]
GERDA physics goal
Ph
ys R
ev D
092
003
(200
6)
F F
eru
glio
A S
tru
mia
F V
issa
ni
NP
B 6
59
Phase IPhase II
18kg (HdMIGEX) enriched (~86) + 15kg natural reach background of 10-2 counts(keVmiddotkgmiddoty) Exposure of 15 kgmiddoty rarr check claim ltm
ββgt le (023-039) eV (Phys Rev C 81 (2010) 028502)
add ~20kg new enr detectors reach background of 10-3 counts(keVmiddotkgmiddoty) Exposure of 100kgmiddoty Trarr
12 gt 15middot1026y
ltmββ
gt le (009-015) eV (Phys Rev C 81 (2010) 028502)
Phase I
Phase II
Sabine Hemmer 727 February 2012
Phase I
Phase II
Background reduction
3400 mwe
Sabine Hemmer 827 February 2012
GERDA situtated in LNGS underground laboratories suppression of cosmic ray muons by factor 106 by overlaying rock
Graded shielding against ambient radiation Rigorous material selection Avoid exposure above ground for detectors
High-purity LAr (64m3) shield and coolant (Option active veto)
Phase I array
Clean room
Steel cryostat with internal copper shield
Ultrapure water (580m3) n moderator Cherenkov medium for μ veto
Lock
Background reduction
ββ
Ge
Multi-site energy deposition inside HP-Ge diode
(Compton scattering)
γγ βCo-60
Point-like (single-site) energy deposition inside one HP-Ge
diode (Range ~ 1mm)
Signal Background
Signal analysis anti-coincidence between detectors pulse shape analysis (PSA)
Sabine Hemmer 927 February 2012
Start of Phase I6 November 2011 Start of Phase I
All 8 enrGe + 4 natGe detectors deployed in GERDA(2 enrGe detectors presently not used for analysis)
natGe 197 kgmiddoty (76 kg)
enrGe 380 kgmiddoty (146 kg)
Sabine Hemmer 1027 February 2012
Energy spectrum
(Unexpected) Background from Argon
101 Bqkg T12
=269 y
pure β emitter Q-value=565keV rarr below region of interest
39Ar
Sabine Hemmer 1127 February 2012
42ArGERDA proposal 42ArnatAr lt 3 x 10-21 (Barabash et al 2002)GERDA measurement Count rate at 1525keV ~ 2 times expectation
Field-free configuration
Region of Interest
middot
Background rate in ROI (Qββ
plusmn100 keV blinded window excluded) enrGe 0017+0009
-0005 counts(keVmiddotkgmiddoty)
natGe 0049+0015-0013
counts(keVmiddotkgmiddoty) most likely a combination of ThU 42K degraded α cosmogenic isotopes factor ~10 lower than previous experiments (HdM IGEX) no pulse shape analysis applied yet
ROI
blinded
ROI
blinded
Sabine Hemmer 1227 February 2012
2νββ
middot
39Ar 101 Bqkg from WARP [NIM A574 83-88 (2007)]
76Ge T12
(2νββ)=174middot1021y from HdM
[NIM A513 596-621 (2003)]
42K homogeneously distributed decays in LAr (normalized to peak)
40K simulated decays in detector holders (normalized to peak)
Sum of MC contributionsData
Sabine Hemmer 1327 February 2012
Phase II detectorscu
rren
t
time [ns]
ββ decay
ACCEPT
γ ray background REJECT
REJECT42K β UTh chain αs
Peculiar pulses
0νββ-like
90 11
γ-bgd
A
A
Sabine Hemmer 1427 February 2012
BEGe production
Sabine Hemmer 1527 February 2012
Crystal pulling at Canberra Oakridge TN USA
BEGe detector diode production Olen BE
BEGe acceptance tests Hades BE
ONGOING ONGOING
ONGOING
First spectra
RampD liquid argon instrumentation
photons
Liquid argon
Detection of coincident liquid argon scintillation
light to discriminate background
LarGe Low-background test facility at LNGS
Sabine Hemmer 1627 February 2012
Also other designs investigated rarr avoid additional background
Combining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Summary
GERDA Phase I started in November 2011 Unexpectedly high contribution from 42Ar decays Background in ROI lower than in previous experiments (~ factor 10)
but slightly higher than design goal 2νββ spectrum well reproduced by MC (taking into account
contributions from 39Ar 42Ar and 40K) Phase II detector production and RampD on LAr scintillation light
readout ongoing
Sabine Hemmer 1727 February 2012
The GERDA collaboration
Sabine Hemmer 1827 February 2012
BackupHdM claim
Nov 1990 - May 2003 717 kg year Bgd 011 counts (keVkgy) 2875 plusmn 687 events (bgd~60) 42σ evidence for 0νββ
(069 ndash 418)middot1025 y (3 σ) Best fit 119middot1025 y
mββ
= (024-058) eV
best fit 044 eV
Note statistical significance depends on background model
Phys Lett B 586 198-212 (2004)
Comparison IGEX
D Gonzalez et al NPB (Proc Suppl) 87 (2000) 278
Sabine Hemmer B127 February 2012
Backup α events
Sabine Hemmer B227 February 2012
Backup calibration
Sabine Hemmer B327 February 2012
BackupNeutrino properties
What we know m
22-m
12=Δm
sun2
m2
2-m1
2=Δmatm
2
θ12
=θsun
θ23
=θatm
θ
13
What we do not know Absolute mass scale Mass hierarchy Phases (δ
13 α
21 α
31)
Nature of the neutrino mass (Dirac or Majorana)
Sabine Hemmer B427 February 2012
Shockley-Ramo TheoremQ(t)=-qmiddotΦ
w(r(t))
BackupPhase II detectors
Ew(r)=-nablaΦ
Sabine Hemmer B527 February 2012
Backup Background reduction
Key issue Low background rate (Phase I 110 HdM)
sensitivitysimϵsdotasdotradic MsdottbΔ E
Possible backgrounds External
γ from Th and U chain neutrons from spallation μ from cosmic rays
Internal cosmogenic 60Co (T
12=53y)
cosmogenic 68Ge (T12
=271d)
Radioactive surface contamination
Sabine Hemmer B627 February 2012
before MS (059 kgy)
after MS (037 kgy)
Backup Play with the electric fieldAdd a mini-shroud (MS)
70 cm
Shroud (already installed to prevent 222Rn concentration)
+ +- -+ +- -
MSV
S-MS=+700V (019 kgy)
VS-MS
=-400V (037 kgy)
Sabine Hemmer B727 February 2012
Backup Muon induced events
dataMC
Spectrum of muon-induced events in Germanium (209 kgy during commissioning)
Estimate of muon veto efficiency for events causing a signal in Ge ε = 987Estimate of muon-induced background at Q
ββ B
μ lt 20middot10-4 countskeVmiddotkgmiddoty
middot
Sabine Hemmer B827 February 2012
Operation of Phase II proto-type detector in LarGeCombining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Also successful read out scintillation light with fibers coupled to SiPMs
Sabine Hemmer B927 February 2012
Backup RampD liquid argon instrumentation
- Pagina 1
- Pagina 2
- Pagina 3
- Pagina 4
- Pagina 5
- Pagina 6
- Pagina 7
- Pagina 8
- Pagina 9
- Pagina 10
- Pagina 11
- Pagina 12
- Pagina 13
- Pagina 14
- Pagina 15
- Pagina 16
- Pagina 17
- Pagina 18
- Pagina 19
- Pagina 20
- Pagina 21
- Pagina 22
- Pagina 23
- Pagina 24
- Pagina 25
- Pagina 26
- Pagina 27
- Pagina 28
-
![Page 4: Searching for Double Beta Decay with GERDA · [1] Eur. Phys. J. A12, 147-154 (2001) [2] Phys. Rev. D 65, 092007 (2002) Claim of signal from parts of HdM: T 1/2 (76Ge) = (0.69 –](https://reader034.fdocuments.us/reader034/viewer/2022050212/5f5e4aaf5c00cd76d9057fc3/html5/thumbnails/4.jpg)
2νββ and 0νββ
Sabine Hemmer 3
n
n p
p
e-
e-
νν2νββ
n
n p
p
e-
e-
ν=ν0νββ
allowed by SM ΔL=0 observed in many isotopes T
12~1019-1021y
Forbidden process in SM needs Majorana neutrino
ΔL=2 (T
12)-1 = G0ν (Q
ββZ)middot |M0ν|2 middot ltm
ββgt2
G0ν (Qββ
Z) Phase space (~Qββ
5)
|M0ν|2 nuclear matrix elementltm
ββgt2=|sum
iU
ei2m
i|2
27 February 2012
Experimental signature
76Ge
Peak at Qββ
2νββ and 0νββ
Sabine Hemmer 427 February 2012
2νββ0νββ
n
n p
p
e-
e-
νν2νββ
n
n p
p
e-
e-
ν=ν0νββ
Searching in 76Ge
Advantages of Germanium
High ε Source = Detector Small instrinsic b High purity Ge Excellent ΔE FWHM ~ (01-02) Well-established technology
Disadvantages of Germanium
High external b Qββ
=2039keV
Small a of 76Ge 78 rarrEnrichment needed
Limited sources of crystal amp detector manufacturers
Sabine Hemmer 527 February 2012
Ssimϵsdotasdotradic MsdottbΔE
S sensitivityε efficiencya abundance of 2νββ isotopeM detector mass
t measured timeb background indexΔE detector resolution
Germanium detector
Previous 76Ge experiments
[1] Eur Phys J A12 147-154 (2001)[2] Phys Rev D 65 092007 (2002)
Claim of signal from parts of HdMT
12 (76Ge) = (069 ndash 418)middot1025y (3σ) (Phys Lett B 586 198-212 (2004))
Sabine Hemmer 627 February 2012
HdM IGEX
Location LNGSHomestake Baksan
Canfranc
Exposure [kgmiddoty] 711 89
Bg [countskeVmiddotkgmiddoty] 011 017
T12
limit (90 CL) [y] 19middot1025 [1] 16middot1025 [2]
GERDA physics goal
Ph
ys R
ev D
092
003
(200
6)
F F
eru
glio
A S
tru
mia
F V
issa
ni
NP
B 6
59
Phase IPhase II
18kg (HdMIGEX) enriched (~86) + 15kg natural reach background of 10-2 counts(keVmiddotkgmiddoty) Exposure of 15 kgmiddoty rarr check claim ltm
ββgt le (023-039) eV (Phys Rev C 81 (2010) 028502)
add ~20kg new enr detectors reach background of 10-3 counts(keVmiddotkgmiddoty) Exposure of 100kgmiddoty Trarr
12 gt 15middot1026y
ltmββ
gt le (009-015) eV (Phys Rev C 81 (2010) 028502)
Phase I
Phase II
Sabine Hemmer 727 February 2012
Phase I
Phase II
Background reduction
3400 mwe
Sabine Hemmer 827 February 2012
GERDA situtated in LNGS underground laboratories suppression of cosmic ray muons by factor 106 by overlaying rock
Graded shielding against ambient radiation Rigorous material selection Avoid exposure above ground for detectors
High-purity LAr (64m3) shield and coolant (Option active veto)
Phase I array
Clean room
Steel cryostat with internal copper shield
Ultrapure water (580m3) n moderator Cherenkov medium for μ veto
Lock
Background reduction
ββ
Ge
Multi-site energy deposition inside HP-Ge diode
(Compton scattering)
γγ βCo-60
Point-like (single-site) energy deposition inside one HP-Ge
diode (Range ~ 1mm)
Signal Background
Signal analysis anti-coincidence between detectors pulse shape analysis (PSA)
Sabine Hemmer 927 February 2012
Start of Phase I6 November 2011 Start of Phase I
All 8 enrGe + 4 natGe detectors deployed in GERDA(2 enrGe detectors presently not used for analysis)
natGe 197 kgmiddoty (76 kg)
enrGe 380 kgmiddoty (146 kg)
Sabine Hemmer 1027 February 2012
Energy spectrum
(Unexpected) Background from Argon
101 Bqkg T12
=269 y
pure β emitter Q-value=565keV rarr below region of interest
39Ar
Sabine Hemmer 1127 February 2012
42ArGERDA proposal 42ArnatAr lt 3 x 10-21 (Barabash et al 2002)GERDA measurement Count rate at 1525keV ~ 2 times expectation
Field-free configuration
Region of Interest
middot
Background rate in ROI (Qββ
plusmn100 keV blinded window excluded) enrGe 0017+0009
-0005 counts(keVmiddotkgmiddoty)
natGe 0049+0015-0013
counts(keVmiddotkgmiddoty) most likely a combination of ThU 42K degraded α cosmogenic isotopes factor ~10 lower than previous experiments (HdM IGEX) no pulse shape analysis applied yet
ROI
blinded
ROI
blinded
Sabine Hemmer 1227 February 2012
2νββ
middot
39Ar 101 Bqkg from WARP [NIM A574 83-88 (2007)]
76Ge T12
(2νββ)=174middot1021y from HdM
[NIM A513 596-621 (2003)]
42K homogeneously distributed decays in LAr (normalized to peak)
40K simulated decays in detector holders (normalized to peak)
Sum of MC contributionsData
Sabine Hemmer 1327 February 2012
Phase II detectorscu
rren
t
time [ns]
ββ decay
ACCEPT
γ ray background REJECT
REJECT42K β UTh chain αs
Peculiar pulses
0νββ-like
90 11
γ-bgd
A
A
Sabine Hemmer 1427 February 2012
BEGe production
Sabine Hemmer 1527 February 2012
Crystal pulling at Canberra Oakridge TN USA
BEGe detector diode production Olen BE
BEGe acceptance tests Hades BE
ONGOING ONGOING
ONGOING
First spectra
RampD liquid argon instrumentation
photons
Liquid argon
Detection of coincident liquid argon scintillation
light to discriminate background
LarGe Low-background test facility at LNGS
Sabine Hemmer 1627 February 2012
Also other designs investigated rarr avoid additional background
Combining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Summary
GERDA Phase I started in November 2011 Unexpectedly high contribution from 42Ar decays Background in ROI lower than in previous experiments (~ factor 10)
but slightly higher than design goal 2νββ spectrum well reproduced by MC (taking into account
contributions from 39Ar 42Ar and 40K) Phase II detector production and RampD on LAr scintillation light
readout ongoing
Sabine Hemmer 1727 February 2012
The GERDA collaboration
Sabine Hemmer 1827 February 2012
BackupHdM claim
Nov 1990 - May 2003 717 kg year Bgd 011 counts (keVkgy) 2875 plusmn 687 events (bgd~60) 42σ evidence for 0νββ
(069 ndash 418)middot1025 y (3 σ) Best fit 119middot1025 y
mββ
= (024-058) eV
best fit 044 eV
Note statistical significance depends on background model
Phys Lett B 586 198-212 (2004)
Comparison IGEX
D Gonzalez et al NPB (Proc Suppl) 87 (2000) 278
Sabine Hemmer B127 February 2012
Backup α events
Sabine Hemmer B227 February 2012
Backup calibration
Sabine Hemmer B327 February 2012
BackupNeutrino properties
What we know m
22-m
12=Δm
sun2
m2
2-m1
2=Δmatm
2
θ12
=θsun
θ23
=θatm
θ
13
What we do not know Absolute mass scale Mass hierarchy Phases (δ
13 α
21 α
31)
Nature of the neutrino mass (Dirac or Majorana)
Sabine Hemmer B427 February 2012
Shockley-Ramo TheoremQ(t)=-qmiddotΦ
w(r(t))
BackupPhase II detectors
Ew(r)=-nablaΦ
Sabine Hemmer B527 February 2012
Backup Background reduction
Key issue Low background rate (Phase I 110 HdM)
sensitivitysimϵsdotasdotradic MsdottbΔ E
Possible backgrounds External
γ from Th and U chain neutrons from spallation μ from cosmic rays
Internal cosmogenic 60Co (T
12=53y)
cosmogenic 68Ge (T12
=271d)
Radioactive surface contamination
Sabine Hemmer B627 February 2012
before MS (059 kgy)
after MS (037 kgy)
Backup Play with the electric fieldAdd a mini-shroud (MS)
70 cm
Shroud (already installed to prevent 222Rn concentration)
+ +- -+ +- -
MSV
S-MS=+700V (019 kgy)
VS-MS
=-400V (037 kgy)
Sabine Hemmer B727 February 2012
Backup Muon induced events
dataMC
Spectrum of muon-induced events in Germanium (209 kgy during commissioning)
Estimate of muon veto efficiency for events causing a signal in Ge ε = 987Estimate of muon-induced background at Q
ββ B
μ lt 20middot10-4 countskeVmiddotkgmiddoty
middot
Sabine Hemmer B827 February 2012
Operation of Phase II proto-type detector in LarGeCombining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Also successful read out scintillation light with fibers coupled to SiPMs
Sabine Hemmer B927 February 2012
Backup RampD liquid argon instrumentation
- Pagina 1
- Pagina 2
- Pagina 3
- Pagina 4
- Pagina 5
- Pagina 6
- Pagina 7
- Pagina 8
- Pagina 9
- Pagina 10
- Pagina 11
- Pagina 12
- Pagina 13
- Pagina 14
- Pagina 15
- Pagina 16
- Pagina 17
- Pagina 18
- Pagina 19
- Pagina 20
- Pagina 21
- Pagina 22
- Pagina 23
- Pagina 24
- Pagina 25
- Pagina 26
- Pagina 27
- Pagina 28
-
![Page 5: Searching for Double Beta Decay with GERDA · [1] Eur. Phys. J. A12, 147-154 (2001) [2] Phys. Rev. D 65, 092007 (2002) Claim of signal from parts of HdM: T 1/2 (76Ge) = (0.69 –](https://reader034.fdocuments.us/reader034/viewer/2022050212/5f5e4aaf5c00cd76d9057fc3/html5/thumbnails/5.jpg)
Experimental signature
76Ge
Peak at Qββ
2νββ and 0νββ
Sabine Hemmer 427 February 2012
2νββ0νββ
n
n p
p
e-
e-
νν2νββ
n
n p
p
e-
e-
ν=ν0νββ
Searching in 76Ge
Advantages of Germanium
High ε Source = Detector Small instrinsic b High purity Ge Excellent ΔE FWHM ~ (01-02) Well-established technology
Disadvantages of Germanium
High external b Qββ
=2039keV
Small a of 76Ge 78 rarrEnrichment needed
Limited sources of crystal amp detector manufacturers
Sabine Hemmer 527 February 2012
Ssimϵsdotasdotradic MsdottbΔE
S sensitivityε efficiencya abundance of 2νββ isotopeM detector mass
t measured timeb background indexΔE detector resolution
Germanium detector
Previous 76Ge experiments
[1] Eur Phys J A12 147-154 (2001)[2] Phys Rev D 65 092007 (2002)
Claim of signal from parts of HdMT
12 (76Ge) = (069 ndash 418)middot1025y (3σ) (Phys Lett B 586 198-212 (2004))
Sabine Hemmer 627 February 2012
HdM IGEX
Location LNGSHomestake Baksan
Canfranc
Exposure [kgmiddoty] 711 89
Bg [countskeVmiddotkgmiddoty] 011 017
T12
limit (90 CL) [y] 19middot1025 [1] 16middot1025 [2]
GERDA physics goal
Ph
ys R
ev D
092
003
(200
6)
F F
eru
glio
A S
tru
mia
F V
issa
ni
NP
B 6
59
Phase IPhase II
18kg (HdMIGEX) enriched (~86) + 15kg natural reach background of 10-2 counts(keVmiddotkgmiddoty) Exposure of 15 kgmiddoty rarr check claim ltm
ββgt le (023-039) eV (Phys Rev C 81 (2010) 028502)
add ~20kg new enr detectors reach background of 10-3 counts(keVmiddotkgmiddoty) Exposure of 100kgmiddoty Trarr
12 gt 15middot1026y
ltmββ
gt le (009-015) eV (Phys Rev C 81 (2010) 028502)
Phase I
Phase II
Sabine Hemmer 727 February 2012
Phase I
Phase II
Background reduction
3400 mwe
Sabine Hemmer 827 February 2012
GERDA situtated in LNGS underground laboratories suppression of cosmic ray muons by factor 106 by overlaying rock
Graded shielding against ambient radiation Rigorous material selection Avoid exposure above ground for detectors
High-purity LAr (64m3) shield and coolant (Option active veto)
Phase I array
Clean room
Steel cryostat with internal copper shield
Ultrapure water (580m3) n moderator Cherenkov medium for μ veto
Lock
Background reduction
ββ
Ge
Multi-site energy deposition inside HP-Ge diode
(Compton scattering)
γγ βCo-60
Point-like (single-site) energy deposition inside one HP-Ge
diode (Range ~ 1mm)
Signal Background
Signal analysis anti-coincidence between detectors pulse shape analysis (PSA)
Sabine Hemmer 927 February 2012
Start of Phase I6 November 2011 Start of Phase I
All 8 enrGe + 4 natGe detectors deployed in GERDA(2 enrGe detectors presently not used for analysis)
natGe 197 kgmiddoty (76 kg)
enrGe 380 kgmiddoty (146 kg)
Sabine Hemmer 1027 February 2012
Energy spectrum
(Unexpected) Background from Argon
101 Bqkg T12
=269 y
pure β emitter Q-value=565keV rarr below region of interest
39Ar
Sabine Hemmer 1127 February 2012
42ArGERDA proposal 42ArnatAr lt 3 x 10-21 (Barabash et al 2002)GERDA measurement Count rate at 1525keV ~ 2 times expectation
Field-free configuration
Region of Interest
middot
Background rate in ROI (Qββ
plusmn100 keV blinded window excluded) enrGe 0017+0009
-0005 counts(keVmiddotkgmiddoty)
natGe 0049+0015-0013
counts(keVmiddotkgmiddoty) most likely a combination of ThU 42K degraded α cosmogenic isotopes factor ~10 lower than previous experiments (HdM IGEX) no pulse shape analysis applied yet
ROI
blinded
ROI
blinded
Sabine Hemmer 1227 February 2012
2νββ
middot
39Ar 101 Bqkg from WARP [NIM A574 83-88 (2007)]
76Ge T12
(2νββ)=174middot1021y from HdM
[NIM A513 596-621 (2003)]
42K homogeneously distributed decays in LAr (normalized to peak)
40K simulated decays in detector holders (normalized to peak)
Sum of MC contributionsData
Sabine Hemmer 1327 February 2012
Phase II detectorscu
rren
t
time [ns]
ββ decay
ACCEPT
γ ray background REJECT
REJECT42K β UTh chain αs
Peculiar pulses
0νββ-like
90 11
γ-bgd
A
A
Sabine Hemmer 1427 February 2012
BEGe production
Sabine Hemmer 1527 February 2012
Crystal pulling at Canberra Oakridge TN USA
BEGe detector diode production Olen BE
BEGe acceptance tests Hades BE
ONGOING ONGOING
ONGOING
First spectra
RampD liquid argon instrumentation
photons
Liquid argon
Detection of coincident liquid argon scintillation
light to discriminate background
LarGe Low-background test facility at LNGS
Sabine Hemmer 1627 February 2012
Also other designs investigated rarr avoid additional background
Combining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Summary
GERDA Phase I started in November 2011 Unexpectedly high contribution from 42Ar decays Background in ROI lower than in previous experiments (~ factor 10)
but slightly higher than design goal 2νββ spectrum well reproduced by MC (taking into account
contributions from 39Ar 42Ar and 40K) Phase II detector production and RampD on LAr scintillation light
readout ongoing
Sabine Hemmer 1727 February 2012
The GERDA collaboration
Sabine Hemmer 1827 February 2012
BackupHdM claim
Nov 1990 - May 2003 717 kg year Bgd 011 counts (keVkgy) 2875 plusmn 687 events (bgd~60) 42σ evidence for 0νββ
(069 ndash 418)middot1025 y (3 σ) Best fit 119middot1025 y
mββ
= (024-058) eV
best fit 044 eV
Note statistical significance depends on background model
Phys Lett B 586 198-212 (2004)
Comparison IGEX
D Gonzalez et al NPB (Proc Suppl) 87 (2000) 278
Sabine Hemmer B127 February 2012
Backup α events
Sabine Hemmer B227 February 2012
Backup calibration
Sabine Hemmer B327 February 2012
BackupNeutrino properties
What we know m
22-m
12=Δm
sun2
m2
2-m1
2=Δmatm
2
θ12
=θsun
θ23
=θatm
θ
13
What we do not know Absolute mass scale Mass hierarchy Phases (δ
13 α
21 α
31)
Nature of the neutrino mass (Dirac or Majorana)
Sabine Hemmer B427 February 2012
Shockley-Ramo TheoremQ(t)=-qmiddotΦ
w(r(t))
BackupPhase II detectors
Ew(r)=-nablaΦ
Sabine Hemmer B527 February 2012
Backup Background reduction
Key issue Low background rate (Phase I 110 HdM)
sensitivitysimϵsdotasdotradic MsdottbΔ E
Possible backgrounds External
γ from Th and U chain neutrons from spallation μ from cosmic rays
Internal cosmogenic 60Co (T
12=53y)
cosmogenic 68Ge (T12
=271d)
Radioactive surface contamination
Sabine Hemmer B627 February 2012
before MS (059 kgy)
after MS (037 kgy)
Backup Play with the electric fieldAdd a mini-shroud (MS)
70 cm
Shroud (already installed to prevent 222Rn concentration)
+ +- -+ +- -
MSV
S-MS=+700V (019 kgy)
VS-MS
=-400V (037 kgy)
Sabine Hemmer B727 February 2012
Backup Muon induced events
dataMC
Spectrum of muon-induced events in Germanium (209 kgy during commissioning)
Estimate of muon veto efficiency for events causing a signal in Ge ε = 987Estimate of muon-induced background at Q
ββ B
μ lt 20middot10-4 countskeVmiddotkgmiddoty
middot
Sabine Hemmer B827 February 2012
Operation of Phase II proto-type detector in LarGeCombining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Also successful read out scintillation light with fibers coupled to SiPMs
Sabine Hemmer B927 February 2012
Backup RampD liquid argon instrumentation
- Pagina 1
- Pagina 2
- Pagina 3
- Pagina 4
- Pagina 5
- Pagina 6
- Pagina 7
- Pagina 8
- Pagina 9
- Pagina 10
- Pagina 11
- Pagina 12
- Pagina 13
- Pagina 14
- Pagina 15
- Pagina 16
- Pagina 17
- Pagina 18
- Pagina 19
- Pagina 20
- Pagina 21
- Pagina 22
- Pagina 23
- Pagina 24
- Pagina 25
- Pagina 26
- Pagina 27
- Pagina 28
-
![Page 6: Searching for Double Beta Decay with GERDA · [1] Eur. Phys. J. A12, 147-154 (2001) [2] Phys. Rev. D 65, 092007 (2002) Claim of signal from parts of HdM: T 1/2 (76Ge) = (0.69 –](https://reader034.fdocuments.us/reader034/viewer/2022050212/5f5e4aaf5c00cd76d9057fc3/html5/thumbnails/6.jpg)
Searching in 76Ge
Advantages of Germanium
High ε Source = Detector Small instrinsic b High purity Ge Excellent ΔE FWHM ~ (01-02) Well-established technology
Disadvantages of Germanium
High external b Qββ
=2039keV
Small a of 76Ge 78 rarrEnrichment needed
Limited sources of crystal amp detector manufacturers
Sabine Hemmer 527 February 2012
Ssimϵsdotasdotradic MsdottbΔE
S sensitivityε efficiencya abundance of 2νββ isotopeM detector mass
t measured timeb background indexΔE detector resolution
Germanium detector
Previous 76Ge experiments
[1] Eur Phys J A12 147-154 (2001)[2] Phys Rev D 65 092007 (2002)
Claim of signal from parts of HdMT
12 (76Ge) = (069 ndash 418)middot1025y (3σ) (Phys Lett B 586 198-212 (2004))
Sabine Hemmer 627 February 2012
HdM IGEX
Location LNGSHomestake Baksan
Canfranc
Exposure [kgmiddoty] 711 89
Bg [countskeVmiddotkgmiddoty] 011 017
T12
limit (90 CL) [y] 19middot1025 [1] 16middot1025 [2]
GERDA physics goal
Ph
ys R
ev D
092
003
(200
6)
F F
eru
glio
A S
tru
mia
F V
issa
ni
NP
B 6
59
Phase IPhase II
18kg (HdMIGEX) enriched (~86) + 15kg natural reach background of 10-2 counts(keVmiddotkgmiddoty) Exposure of 15 kgmiddoty rarr check claim ltm
ββgt le (023-039) eV (Phys Rev C 81 (2010) 028502)
add ~20kg new enr detectors reach background of 10-3 counts(keVmiddotkgmiddoty) Exposure of 100kgmiddoty Trarr
12 gt 15middot1026y
ltmββ
gt le (009-015) eV (Phys Rev C 81 (2010) 028502)
Phase I
Phase II
Sabine Hemmer 727 February 2012
Phase I
Phase II
Background reduction
3400 mwe
Sabine Hemmer 827 February 2012
GERDA situtated in LNGS underground laboratories suppression of cosmic ray muons by factor 106 by overlaying rock
Graded shielding against ambient radiation Rigorous material selection Avoid exposure above ground for detectors
High-purity LAr (64m3) shield and coolant (Option active veto)
Phase I array
Clean room
Steel cryostat with internal copper shield
Ultrapure water (580m3) n moderator Cherenkov medium for μ veto
Lock
Background reduction
ββ
Ge
Multi-site energy deposition inside HP-Ge diode
(Compton scattering)
γγ βCo-60
Point-like (single-site) energy deposition inside one HP-Ge
diode (Range ~ 1mm)
Signal Background
Signal analysis anti-coincidence between detectors pulse shape analysis (PSA)
Sabine Hemmer 927 February 2012
Start of Phase I6 November 2011 Start of Phase I
All 8 enrGe + 4 natGe detectors deployed in GERDA(2 enrGe detectors presently not used for analysis)
natGe 197 kgmiddoty (76 kg)
enrGe 380 kgmiddoty (146 kg)
Sabine Hemmer 1027 February 2012
Energy spectrum
(Unexpected) Background from Argon
101 Bqkg T12
=269 y
pure β emitter Q-value=565keV rarr below region of interest
39Ar
Sabine Hemmer 1127 February 2012
42ArGERDA proposal 42ArnatAr lt 3 x 10-21 (Barabash et al 2002)GERDA measurement Count rate at 1525keV ~ 2 times expectation
Field-free configuration
Region of Interest
middot
Background rate in ROI (Qββ
plusmn100 keV blinded window excluded) enrGe 0017+0009
-0005 counts(keVmiddotkgmiddoty)
natGe 0049+0015-0013
counts(keVmiddotkgmiddoty) most likely a combination of ThU 42K degraded α cosmogenic isotopes factor ~10 lower than previous experiments (HdM IGEX) no pulse shape analysis applied yet
ROI
blinded
ROI
blinded
Sabine Hemmer 1227 February 2012
2νββ
middot
39Ar 101 Bqkg from WARP [NIM A574 83-88 (2007)]
76Ge T12
(2νββ)=174middot1021y from HdM
[NIM A513 596-621 (2003)]
42K homogeneously distributed decays in LAr (normalized to peak)
40K simulated decays in detector holders (normalized to peak)
Sum of MC contributionsData
Sabine Hemmer 1327 February 2012
Phase II detectorscu
rren
t
time [ns]
ββ decay
ACCEPT
γ ray background REJECT
REJECT42K β UTh chain αs
Peculiar pulses
0νββ-like
90 11
γ-bgd
A
A
Sabine Hemmer 1427 February 2012
BEGe production
Sabine Hemmer 1527 February 2012
Crystal pulling at Canberra Oakridge TN USA
BEGe detector diode production Olen BE
BEGe acceptance tests Hades BE
ONGOING ONGOING
ONGOING
First spectra
RampD liquid argon instrumentation
photons
Liquid argon
Detection of coincident liquid argon scintillation
light to discriminate background
LarGe Low-background test facility at LNGS
Sabine Hemmer 1627 February 2012
Also other designs investigated rarr avoid additional background
Combining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Summary
GERDA Phase I started in November 2011 Unexpectedly high contribution from 42Ar decays Background in ROI lower than in previous experiments (~ factor 10)
but slightly higher than design goal 2νββ spectrum well reproduced by MC (taking into account
contributions from 39Ar 42Ar and 40K) Phase II detector production and RampD on LAr scintillation light
readout ongoing
Sabine Hemmer 1727 February 2012
The GERDA collaboration
Sabine Hemmer 1827 February 2012
BackupHdM claim
Nov 1990 - May 2003 717 kg year Bgd 011 counts (keVkgy) 2875 plusmn 687 events (bgd~60) 42σ evidence for 0νββ
(069 ndash 418)middot1025 y (3 σ) Best fit 119middot1025 y
mββ
= (024-058) eV
best fit 044 eV
Note statistical significance depends on background model
Phys Lett B 586 198-212 (2004)
Comparison IGEX
D Gonzalez et al NPB (Proc Suppl) 87 (2000) 278
Sabine Hemmer B127 February 2012
Backup α events
Sabine Hemmer B227 February 2012
Backup calibration
Sabine Hemmer B327 February 2012
BackupNeutrino properties
What we know m
22-m
12=Δm
sun2
m2
2-m1
2=Δmatm
2
θ12
=θsun
θ23
=θatm
θ
13
What we do not know Absolute mass scale Mass hierarchy Phases (δ
13 α
21 α
31)
Nature of the neutrino mass (Dirac or Majorana)
Sabine Hemmer B427 February 2012
Shockley-Ramo TheoremQ(t)=-qmiddotΦ
w(r(t))
BackupPhase II detectors
Ew(r)=-nablaΦ
Sabine Hemmer B527 February 2012
Backup Background reduction
Key issue Low background rate (Phase I 110 HdM)
sensitivitysimϵsdotasdotradic MsdottbΔ E
Possible backgrounds External
γ from Th and U chain neutrons from spallation μ from cosmic rays
Internal cosmogenic 60Co (T
12=53y)
cosmogenic 68Ge (T12
=271d)
Radioactive surface contamination
Sabine Hemmer B627 February 2012
before MS (059 kgy)
after MS (037 kgy)
Backup Play with the electric fieldAdd a mini-shroud (MS)
70 cm
Shroud (already installed to prevent 222Rn concentration)
+ +- -+ +- -
MSV
S-MS=+700V (019 kgy)
VS-MS
=-400V (037 kgy)
Sabine Hemmer B727 February 2012
Backup Muon induced events
dataMC
Spectrum of muon-induced events in Germanium (209 kgy during commissioning)
Estimate of muon veto efficiency for events causing a signal in Ge ε = 987Estimate of muon-induced background at Q
ββ B
μ lt 20middot10-4 countskeVmiddotkgmiddoty
middot
Sabine Hemmer B827 February 2012
Operation of Phase II proto-type detector in LarGeCombining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Also successful read out scintillation light with fibers coupled to SiPMs
Sabine Hemmer B927 February 2012
Backup RampD liquid argon instrumentation
- Pagina 1
- Pagina 2
- Pagina 3
- Pagina 4
- Pagina 5
- Pagina 6
- Pagina 7
- Pagina 8
- Pagina 9
- Pagina 10
- Pagina 11
- Pagina 12
- Pagina 13
- Pagina 14
- Pagina 15
- Pagina 16
- Pagina 17
- Pagina 18
- Pagina 19
- Pagina 20
- Pagina 21
- Pagina 22
- Pagina 23
- Pagina 24
- Pagina 25
- Pagina 26
- Pagina 27
- Pagina 28
-
![Page 7: Searching for Double Beta Decay with GERDA · [1] Eur. Phys. J. A12, 147-154 (2001) [2] Phys. Rev. D 65, 092007 (2002) Claim of signal from parts of HdM: T 1/2 (76Ge) = (0.69 –](https://reader034.fdocuments.us/reader034/viewer/2022050212/5f5e4aaf5c00cd76d9057fc3/html5/thumbnails/7.jpg)
Previous 76Ge experiments
[1] Eur Phys J A12 147-154 (2001)[2] Phys Rev D 65 092007 (2002)
Claim of signal from parts of HdMT
12 (76Ge) = (069 ndash 418)middot1025y (3σ) (Phys Lett B 586 198-212 (2004))
Sabine Hemmer 627 February 2012
HdM IGEX
Location LNGSHomestake Baksan
Canfranc
Exposure [kgmiddoty] 711 89
Bg [countskeVmiddotkgmiddoty] 011 017
T12
limit (90 CL) [y] 19middot1025 [1] 16middot1025 [2]
GERDA physics goal
Ph
ys R
ev D
092
003
(200
6)
F F
eru
glio
A S
tru
mia
F V
issa
ni
NP
B 6
59
Phase IPhase II
18kg (HdMIGEX) enriched (~86) + 15kg natural reach background of 10-2 counts(keVmiddotkgmiddoty) Exposure of 15 kgmiddoty rarr check claim ltm
ββgt le (023-039) eV (Phys Rev C 81 (2010) 028502)
add ~20kg new enr detectors reach background of 10-3 counts(keVmiddotkgmiddoty) Exposure of 100kgmiddoty Trarr
12 gt 15middot1026y
ltmββ
gt le (009-015) eV (Phys Rev C 81 (2010) 028502)
Phase I
Phase II
Sabine Hemmer 727 February 2012
Phase I
Phase II
Background reduction
3400 mwe
Sabine Hemmer 827 February 2012
GERDA situtated in LNGS underground laboratories suppression of cosmic ray muons by factor 106 by overlaying rock
Graded shielding against ambient radiation Rigorous material selection Avoid exposure above ground for detectors
High-purity LAr (64m3) shield and coolant (Option active veto)
Phase I array
Clean room
Steel cryostat with internal copper shield
Ultrapure water (580m3) n moderator Cherenkov medium for μ veto
Lock
Background reduction
ββ
Ge
Multi-site energy deposition inside HP-Ge diode
(Compton scattering)
γγ βCo-60
Point-like (single-site) energy deposition inside one HP-Ge
diode (Range ~ 1mm)
Signal Background
Signal analysis anti-coincidence between detectors pulse shape analysis (PSA)
Sabine Hemmer 927 February 2012
Start of Phase I6 November 2011 Start of Phase I
All 8 enrGe + 4 natGe detectors deployed in GERDA(2 enrGe detectors presently not used for analysis)
natGe 197 kgmiddoty (76 kg)
enrGe 380 kgmiddoty (146 kg)
Sabine Hemmer 1027 February 2012
Energy spectrum
(Unexpected) Background from Argon
101 Bqkg T12
=269 y
pure β emitter Q-value=565keV rarr below region of interest
39Ar
Sabine Hemmer 1127 February 2012
42ArGERDA proposal 42ArnatAr lt 3 x 10-21 (Barabash et al 2002)GERDA measurement Count rate at 1525keV ~ 2 times expectation
Field-free configuration
Region of Interest
middot
Background rate in ROI (Qββ
plusmn100 keV blinded window excluded) enrGe 0017+0009
-0005 counts(keVmiddotkgmiddoty)
natGe 0049+0015-0013
counts(keVmiddotkgmiddoty) most likely a combination of ThU 42K degraded α cosmogenic isotopes factor ~10 lower than previous experiments (HdM IGEX) no pulse shape analysis applied yet
ROI
blinded
ROI
blinded
Sabine Hemmer 1227 February 2012
2νββ
middot
39Ar 101 Bqkg from WARP [NIM A574 83-88 (2007)]
76Ge T12
(2νββ)=174middot1021y from HdM
[NIM A513 596-621 (2003)]
42K homogeneously distributed decays in LAr (normalized to peak)
40K simulated decays in detector holders (normalized to peak)
Sum of MC contributionsData
Sabine Hemmer 1327 February 2012
Phase II detectorscu
rren
t
time [ns]
ββ decay
ACCEPT
γ ray background REJECT
REJECT42K β UTh chain αs
Peculiar pulses
0νββ-like
90 11
γ-bgd
A
A
Sabine Hemmer 1427 February 2012
BEGe production
Sabine Hemmer 1527 February 2012
Crystal pulling at Canberra Oakridge TN USA
BEGe detector diode production Olen BE
BEGe acceptance tests Hades BE
ONGOING ONGOING
ONGOING
First spectra
RampD liquid argon instrumentation
photons
Liquid argon
Detection of coincident liquid argon scintillation
light to discriminate background
LarGe Low-background test facility at LNGS
Sabine Hemmer 1627 February 2012
Also other designs investigated rarr avoid additional background
Combining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Summary
GERDA Phase I started in November 2011 Unexpectedly high contribution from 42Ar decays Background in ROI lower than in previous experiments (~ factor 10)
but slightly higher than design goal 2νββ spectrum well reproduced by MC (taking into account
contributions from 39Ar 42Ar and 40K) Phase II detector production and RampD on LAr scintillation light
readout ongoing
Sabine Hemmer 1727 February 2012
The GERDA collaboration
Sabine Hemmer 1827 February 2012
BackupHdM claim
Nov 1990 - May 2003 717 kg year Bgd 011 counts (keVkgy) 2875 plusmn 687 events (bgd~60) 42σ evidence for 0νββ
(069 ndash 418)middot1025 y (3 σ) Best fit 119middot1025 y
mββ
= (024-058) eV
best fit 044 eV
Note statistical significance depends on background model
Phys Lett B 586 198-212 (2004)
Comparison IGEX
D Gonzalez et al NPB (Proc Suppl) 87 (2000) 278
Sabine Hemmer B127 February 2012
Backup α events
Sabine Hemmer B227 February 2012
Backup calibration
Sabine Hemmer B327 February 2012
BackupNeutrino properties
What we know m
22-m
12=Δm
sun2
m2
2-m1
2=Δmatm
2
θ12
=θsun
θ23
=θatm
θ
13
What we do not know Absolute mass scale Mass hierarchy Phases (δ
13 α
21 α
31)
Nature of the neutrino mass (Dirac or Majorana)
Sabine Hemmer B427 February 2012
Shockley-Ramo TheoremQ(t)=-qmiddotΦ
w(r(t))
BackupPhase II detectors
Ew(r)=-nablaΦ
Sabine Hemmer B527 February 2012
Backup Background reduction
Key issue Low background rate (Phase I 110 HdM)
sensitivitysimϵsdotasdotradic MsdottbΔ E
Possible backgrounds External
γ from Th and U chain neutrons from spallation μ from cosmic rays
Internal cosmogenic 60Co (T
12=53y)
cosmogenic 68Ge (T12
=271d)
Radioactive surface contamination
Sabine Hemmer B627 February 2012
before MS (059 kgy)
after MS (037 kgy)
Backup Play with the electric fieldAdd a mini-shroud (MS)
70 cm
Shroud (already installed to prevent 222Rn concentration)
+ +- -+ +- -
MSV
S-MS=+700V (019 kgy)
VS-MS
=-400V (037 kgy)
Sabine Hemmer B727 February 2012
Backup Muon induced events
dataMC
Spectrum of muon-induced events in Germanium (209 kgy during commissioning)
Estimate of muon veto efficiency for events causing a signal in Ge ε = 987Estimate of muon-induced background at Q
ββ B
μ lt 20middot10-4 countskeVmiddotkgmiddoty
middot
Sabine Hemmer B827 February 2012
Operation of Phase II proto-type detector in LarGeCombining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Also successful read out scintillation light with fibers coupled to SiPMs
Sabine Hemmer B927 February 2012
Backup RampD liquid argon instrumentation
- Pagina 1
- Pagina 2
- Pagina 3
- Pagina 4
- Pagina 5
- Pagina 6
- Pagina 7
- Pagina 8
- Pagina 9
- Pagina 10
- Pagina 11
- Pagina 12
- Pagina 13
- Pagina 14
- Pagina 15
- Pagina 16
- Pagina 17
- Pagina 18
- Pagina 19
- Pagina 20
- Pagina 21
- Pagina 22
- Pagina 23
- Pagina 24
- Pagina 25
- Pagina 26
- Pagina 27
- Pagina 28
-
![Page 8: Searching for Double Beta Decay with GERDA · [1] Eur. Phys. J. A12, 147-154 (2001) [2] Phys. Rev. D 65, 092007 (2002) Claim of signal from parts of HdM: T 1/2 (76Ge) = (0.69 –](https://reader034.fdocuments.us/reader034/viewer/2022050212/5f5e4aaf5c00cd76d9057fc3/html5/thumbnails/8.jpg)
GERDA physics goal
Ph
ys R
ev D
092
003
(200
6)
F F
eru
glio
A S
tru
mia
F V
issa
ni
NP
B 6
59
Phase IPhase II
18kg (HdMIGEX) enriched (~86) + 15kg natural reach background of 10-2 counts(keVmiddotkgmiddoty) Exposure of 15 kgmiddoty rarr check claim ltm
ββgt le (023-039) eV (Phys Rev C 81 (2010) 028502)
add ~20kg new enr detectors reach background of 10-3 counts(keVmiddotkgmiddoty) Exposure of 100kgmiddoty Trarr
12 gt 15middot1026y
ltmββ
gt le (009-015) eV (Phys Rev C 81 (2010) 028502)
Phase I
Phase II
Sabine Hemmer 727 February 2012
Phase I
Phase II
Background reduction
3400 mwe
Sabine Hemmer 827 February 2012
GERDA situtated in LNGS underground laboratories suppression of cosmic ray muons by factor 106 by overlaying rock
Graded shielding against ambient radiation Rigorous material selection Avoid exposure above ground for detectors
High-purity LAr (64m3) shield and coolant (Option active veto)
Phase I array
Clean room
Steel cryostat with internal copper shield
Ultrapure water (580m3) n moderator Cherenkov medium for μ veto
Lock
Background reduction
ββ
Ge
Multi-site energy deposition inside HP-Ge diode
(Compton scattering)
γγ βCo-60
Point-like (single-site) energy deposition inside one HP-Ge
diode (Range ~ 1mm)
Signal Background
Signal analysis anti-coincidence between detectors pulse shape analysis (PSA)
Sabine Hemmer 927 February 2012
Start of Phase I6 November 2011 Start of Phase I
All 8 enrGe + 4 natGe detectors deployed in GERDA(2 enrGe detectors presently not used for analysis)
natGe 197 kgmiddoty (76 kg)
enrGe 380 kgmiddoty (146 kg)
Sabine Hemmer 1027 February 2012
Energy spectrum
(Unexpected) Background from Argon
101 Bqkg T12
=269 y
pure β emitter Q-value=565keV rarr below region of interest
39Ar
Sabine Hemmer 1127 February 2012
42ArGERDA proposal 42ArnatAr lt 3 x 10-21 (Barabash et al 2002)GERDA measurement Count rate at 1525keV ~ 2 times expectation
Field-free configuration
Region of Interest
middot
Background rate in ROI (Qββ
plusmn100 keV blinded window excluded) enrGe 0017+0009
-0005 counts(keVmiddotkgmiddoty)
natGe 0049+0015-0013
counts(keVmiddotkgmiddoty) most likely a combination of ThU 42K degraded α cosmogenic isotopes factor ~10 lower than previous experiments (HdM IGEX) no pulse shape analysis applied yet
ROI
blinded
ROI
blinded
Sabine Hemmer 1227 February 2012
2νββ
middot
39Ar 101 Bqkg from WARP [NIM A574 83-88 (2007)]
76Ge T12
(2νββ)=174middot1021y from HdM
[NIM A513 596-621 (2003)]
42K homogeneously distributed decays in LAr (normalized to peak)
40K simulated decays in detector holders (normalized to peak)
Sum of MC contributionsData
Sabine Hemmer 1327 February 2012
Phase II detectorscu
rren
t
time [ns]
ββ decay
ACCEPT
γ ray background REJECT
REJECT42K β UTh chain αs
Peculiar pulses
0νββ-like
90 11
γ-bgd
A
A
Sabine Hemmer 1427 February 2012
BEGe production
Sabine Hemmer 1527 February 2012
Crystal pulling at Canberra Oakridge TN USA
BEGe detector diode production Olen BE
BEGe acceptance tests Hades BE
ONGOING ONGOING
ONGOING
First spectra
RampD liquid argon instrumentation
photons
Liquid argon
Detection of coincident liquid argon scintillation
light to discriminate background
LarGe Low-background test facility at LNGS
Sabine Hemmer 1627 February 2012
Also other designs investigated rarr avoid additional background
Combining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Summary
GERDA Phase I started in November 2011 Unexpectedly high contribution from 42Ar decays Background in ROI lower than in previous experiments (~ factor 10)
but slightly higher than design goal 2νββ spectrum well reproduced by MC (taking into account
contributions from 39Ar 42Ar and 40K) Phase II detector production and RampD on LAr scintillation light
readout ongoing
Sabine Hemmer 1727 February 2012
The GERDA collaboration
Sabine Hemmer 1827 February 2012
BackupHdM claim
Nov 1990 - May 2003 717 kg year Bgd 011 counts (keVkgy) 2875 plusmn 687 events (bgd~60) 42σ evidence for 0νββ
(069 ndash 418)middot1025 y (3 σ) Best fit 119middot1025 y
mββ
= (024-058) eV
best fit 044 eV
Note statistical significance depends on background model
Phys Lett B 586 198-212 (2004)
Comparison IGEX
D Gonzalez et al NPB (Proc Suppl) 87 (2000) 278
Sabine Hemmer B127 February 2012
Backup α events
Sabine Hemmer B227 February 2012
Backup calibration
Sabine Hemmer B327 February 2012
BackupNeutrino properties
What we know m
22-m
12=Δm
sun2
m2
2-m1
2=Δmatm
2
θ12
=θsun
θ23
=θatm
θ
13
What we do not know Absolute mass scale Mass hierarchy Phases (δ
13 α
21 α
31)
Nature of the neutrino mass (Dirac or Majorana)
Sabine Hemmer B427 February 2012
Shockley-Ramo TheoremQ(t)=-qmiddotΦ
w(r(t))
BackupPhase II detectors
Ew(r)=-nablaΦ
Sabine Hemmer B527 February 2012
Backup Background reduction
Key issue Low background rate (Phase I 110 HdM)
sensitivitysimϵsdotasdotradic MsdottbΔ E
Possible backgrounds External
γ from Th and U chain neutrons from spallation μ from cosmic rays
Internal cosmogenic 60Co (T
12=53y)
cosmogenic 68Ge (T12
=271d)
Radioactive surface contamination
Sabine Hemmer B627 February 2012
before MS (059 kgy)
after MS (037 kgy)
Backup Play with the electric fieldAdd a mini-shroud (MS)
70 cm
Shroud (already installed to prevent 222Rn concentration)
+ +- -+ +- -
MSV
S-MS=+700V (019 kgy)
VS-MS
=-400V (037 kgy)
Sabine Hemmer B727 February 2012
Backup Muon induced events
dataMC
Spectrum of muon-induced events in Germanium (209 kgy during commissioning)
Estimate of muon veto efficiency for events causing a signal in Ge ε = 987Estimate of muon-induced background at Q
ββ B
μ lt 20middot10-4 countskeVmiddotkgmiddoty
middot
Sabine Hemmer B827 February 2012
Operation of Phase II proto-type detector in LarGeCombining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Also successful read out scintillation light with fibers coupled to SiPMs
Sabine Hemmer B927 February 2012
Backup RampD liquid argon instrumentation
- Pagina 1
- Pagina 2
- Pagina 3
- Pagina 4
- Pagina 5
- Pagina 6
- Pagina 7
- Pagina 8
- Pagina 9
- Pagina 10
- Pagina 11
- Pagina 12
- Pagina 13
- Pagina 14
- Pagina 15
- Pagina 16
- Pagina 17
- Pagina 18
- Pagina 19
- Pagina 20
- Pagina 21
- Pagina 22
- Pagina 23
- Pagina 24
- Pagina 25
- Pagina 26
- Pagina 27
- Pagina 28
-
![Page 9: Searching for Double Beta Decay with GERDA · [1] Eur. Phys. J. A12, 147-154 (2001) [2] Phys. Rev. D 65, 092007 (2002) Claim of signal from parts of HdM: T 1/2 (76Ge) = (0.69 –](https://reader034.fdocuments.us/reader034/viewer/2022050212/5f5e4aaf5c00cd76d9057fc3/html5/thumbnails/9.jpg)
Background reduction
3400 mwe
Sabine Hemmer 827 February 2012
GERDA situtated in LNGS underground laboratories suppression of cosmic ray muons by factor 106 by overlaying rock
Graded shielding against ambient radiation Rigorous material selection Avoid exposure above ground for detectors
High-purity LAr (64m3) shield and coolant (Option active veto)
Phase I array
Clean room
Steel cryostat with internal copper shield
Ultrapure water (580m3) n moderator Cherenkov medium for μ veto
Lock
Background reduction
ββ
Ge
Multi-site energy deposition inside HP-Ge diode
(Compton scattering)
γγ βCo-60
Point-like (single-site) energy deposition inside one HP-Ge
diode (Range ~ 1mm)
Signal Background
Signal analysis anti-coincidence between detectors pulse shape analysis (PSA)
Sabine Hemmer 927 February 2012
Start of Phase I6 November 2011 Start of Phase I
All 8 enrGe + 4 natGe detectors deployed in GERDA(2 enrGe detectors presently not used for analysis)
natGe 197 kgmiddoty (76 kg)
enrGe 380 kgmiddoty (146 kg)
Sabine Hemmer 1027 February 2012
Energy spectrum
(Unexpected) Background from Argon
101 Bqkg T12
=269 y
pure β emitter Q-value=565keV rarr below region of interest
39Ar
Sabine Hemmer 1127 February 2012
42ArGERDA proposal 42ArnatAr lt 3 x 10-21 (Barabash et al 2002)GERDA measurement Count rate at 1525keV ~ 2 times expectation
Field-free configuration
Region of Interest
middot
Background rate in ROI (Qββ
plusmn100 keV blinded window excluded) enrGe 0017+0009
-0005 counts(keVmiddotkgmiddoty)
natGe 0049+0015-0013
counts(keVmiddotkgmiddoty) most likely a combination of ThU 42K degraded α cosmogenic isotopes factor ~10 lower than previous experiments (HdM IGEX) no pulse shape analysis applied yet
ROI
blinded
ROI
blinded
Sabine Hemmer 1227 February 2012
2νββ
middot
39Ar 101 Bqkg from WARP [NIM A574 83-88 (2007)]
76Ge T12
(2νββ)=174middot1021y from HdM
[NIM A513 596-621 (2003)]
42K homogeneously distributed decays in LAr (normalized to peak)
40K simulated decays in detector holders (normalized to peak)
Sum of MC contributionsData
Sabine Hemmer 1327 February 2012
Phase II detectorscu
rren
t
time [ns]
ββ decay
ACCEPT
γ ray background REJECT
REJECT42K β UTh chain αs
Peculiar pulses
0νββ-like
90 11
γ-bgd
A
A
Sabine Hemmer 1427 February 2012
BEGe production
Sabine Hemmer 1527 February 2012
Crystal pulling at Canberra Oakridge TN USA
BEGe detector diode production Olen BE
BEGe acceptance tests Hades BE
ONGOING ONGOING
ONGOING
First spectra
RampD liquid argon instrumentation
photons
Liquid argon
Detection of coincident liquid argon scintillation
light to discriminate background
LarGe Low-background test facility at LNGS
Sabine Hemmer 1627 February 2012
Also other designs investigated rarr avoid additional background
Combining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Summary
GERDA Phase I started in November 2011 Unexpectedly high contribution from 42Ar decays Background in ROI lower than in previous experiments (~ factor 10)
but slightly higher than design goal 2νββ spectrum well reproduced by MC (taking into account
contributions from 39Ar 42Ar and 40K) Phase II detector production and RampD on LAr scintillation light
readout ongoing
Sabine Hemmer 1727 February 2012
The GERDA collaboration
Sabine Hemmer 1827 February 2012
BackupHdM claim
Nov 1990 - May 2003 717 kg year Bgd 011 counts (keVkgy) 2875 plusmn 687 events (bgd~60) 42σ evidence for 0νββ
(069 ndash 418)middot1025 y (3 σ) Best fit 119middot1025 y
mββ
= (024-058) eV
best fit 044 eV
Note statistical significance depends on background model
Phys Lett B 586 198-212 (2004)
Comparison IGEX
D Gonzalez et al NPB (Proc Suppl) 87 (2000) 278
Sabine Hemmer B127 February 2012
Backup α events
Sabine Hemmer B227 February 2012
Backup calibration
Sabine Hemmer B327 February 2012
BackupNeutrino properties
What we know m
22-m
12=Δm
sun2
m2
2-m1
2=Δmatm
2
θ12
=θsun
θ23
=θatm
θ
13
What we do not know Absolute mass scale Mass hierarchy Phases (δ
13 α
21 α
31)
Nature of the neutrino mass (Dirac or Majorana)
Sabine Hemmer B427 February 2012
Shockley-Ramo TheoremQ(t)=-qmiddotΦ
w(r(t))
BackupPhase II detectors
Ew(r)=-nablaΦ
Sabine Hemmer B527 February 2012
Backup Background reduction
Key issue Low background rate (Phase I 110 HdM)
sensitivitysimϵsdotasdotradic MsdottbΔ E
Possible backgrounds External
γ from Th and U chain neutrons from spallation μ from cosmic rays
Internal cosmogenic 60Co (T
12=53y)
cosmogenic 68Ge (T12
=271d)
Radioactive surface contamination
Sabine Hemmer B627 February 2012
before MS (059 kgy)
after MS (037 kgy)
Backup Play with the electric fieldAdd a mini-shroud (MS)
70 cm
Shroud (already installed to prevent 222Rn concentration)
+ +- -+ +- -
MSV
S-MS=+700V (019 kgy)
VS-MS
=-400V (037 kgy)
Sabine Hemmer B727 February 2012
Backup Muon induced events
dataMC
Spectrum of muon-induced events in Germanium (209 kgy during commissioning)
Estimate of muon veto efficiency for events causing a signal in Ge ε = 987Estimate of muon-induced background at Q
ββ B
μ lt 20middot10-4 countskeVmiddotkgmiddoty
middot
Sabine Hemmer B827 February 2012
Operation of Phase II proto-type detector in LarGeCombining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Also successful read out scintillation light with fibers coupled to SiPMs
Sabine Hemmer B927 February 2012
Backup RampD liquid argon instrumentation
- Pagina 1
- Pagina 2
- Pagina 3
- Pagina 4
- Pagina 5
- Pagina 6
- Pagina 7
- Pagina 8
- Pagina 9
- Pagina 10
- Pagina 11
- Pagina 12
- Pagina 13
- Pagina 14
- Pagina 15
- Pagina 16
- Pagina 17
- Pagina 18
- Pagina 19
- Pagina 20
- Pagina 21
- Pagina 22
- Pagina 23
- Pagina 24
- Pagina 25
- Pagina 26
- Pagina 27
- Pagina 28
-
![Page 10: Searching for Double Beta Decay with GERDA · [1] Eur. Phys. J. A12, 147-154 (2001) [2] Phys. Rev. D 65, 092007 (2002) Claim of signal from parts of HdM: T 1/2 (76Ge) = (0.69 –](https://reader034.fdocuments.us/reader034/viewer/2022050212/5f5e4aaf5c00cd76d9057fc3/html5/thumbnails/10.jpg)
Background reduction
ββ
Ge
Multi-site energy deposition inside HP-Ge diode
(Compton scattering)
γγ βCo-60
Point-like (single-site) energy deposition inside one HP-Ge
diode (Range ~ 1mm)
Signal Background
Signal analysis anti-coincidence between detectors pulse shape analysis (PSA)
Sabine Hemmer 927 February 2012
Start of Phase I6 November 2011 Start of Phase I
All 8 enrGe + 4 natGe detectors deployed in GERDA(2 enrGe detectors presently not used for analysis)
natGe 197 kgmiddoty (76 kg)
enrGe 380 kgmiddoty (146 kg)
Sabine Hemmer 1027 February 2012
Energy spectrum
(Unexpected) Background from Argon
101 Bqkg T12
=269 y
pure β emitter Q-value=565keV rarr below region of interest
39Ar
Sabine Hemmer 1127 February 2012
42ArGERDA proposal 42ArnatAr lt 3 x 10-21 (Barabash et al 2002)GERDA measurement Count rate at 1525keV ~ 2 times expectation
Field-free configuration
Region of Interest
middot
Background rate in ROI (Qββ
plusmn100 keV blinded window excluded) enrGe 0017+0009
-0005 counts(keVmiddotkgmiddoty)
natGe 0049+0015-0013
counts(keVmiddotkgmiddoty) most likely a combination of ThU 42K degraded α cosmogenic isotopes factor ~10 lower than previous experiments (HdM IGEX) no pulse shape analysis applied yet
ROI
blinded
ROI
blinded
Sabine Hemmer 1227 February 2012
2νββ
middot
39Ar 101 Bqkg from WARP [NIM A574 83-88 (2007)]
76Ge T12
(2νββ)=174middot1021y from HdM
[NIM A513 596-621 (2003)]
42K homogeneously distributed decays in LAr (normalized to peak)
40K simulated decays in detector holders (normalized to peak)
Sum of MC contributionsData
Sabine Hemmer 1327 February 2012
Phase II detectorscu
rren
t
time [ns]
ββ decay
ACCEPT
γ ray background REJECT
REJECT42K β UTh chain αs
Peculiar pulses
0νββ-like
90 11
γ-bgd
A
A
Sabine Hemmer 1427 February 2012
BEGe production
Sabine Hemmer 1527 February 2012
Crystal pulling at Canberra Oakridge TN USA
BEGe detector diode production Olen BE
BEGe acceptance tests Hades BE
ONGOING ONGOING
ONGOING
First spectra
RampD liquid argon instrumentation
photons
Liquid argon
Detection of coincident liquid argon scintillation
light to discriminate background
LarGe Low-background test facility at LNGS
Sabine Hemmer 1627 February 2012
Also other designs investigated rarr avoid additional background
Combining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Summary
GERDA Phase I started in November 2011 Unexpectedly high contribution from 42Ar decays Background in ROI lower than in previous experiments (~ factor 10)
but slightly higher than design goal 2νββ spectrum well reproduced by MC (taking into account
contributions from 39Ar 42Ar and 40K) Phase II detector production and RampD on LAr scintillation light
readout ongoing
Sabine Hemmer 1727 February 2012
The GERDA collaboration
Sabine Hemmer 1827 February 2012
BackupHdM claim
Nov 1990 - May 2003 717 kg year Bgd 011 counts (keVkgy) 2875 plusmn 687 events (bgd~60) 42σ evidence for 0νββ
(069 ndash 418)middot1025 y (3 σ) Best fit 119middot1025 y
mββ
= (024-058) eV
best fit 044 eV
Note statistical significance depends on background model
Phys Lett B 586 198-212 (2004)
Comparison IGEX
D Gonzalez et al NPB (Proc Suppl) 87 (2000) 278
Sabine Hemmer B127 February 2012
Backup α events
Sabine Hemmer B227 February 2012
Backup calibration
Sabine Hemmer B327 February 2012
BackupNeutrino properties
What we know m
22-m
12=Δm
sun2
m2
2-m1
2=Δmatm
2
θ12
=θsun
θ23
=θatm
θ
13
What we do not know Absolute mass scale Mass hierarchy Phases (δ
13 α
21 α
31)
Nature of the neutrino mass (Dirac or Majorana)
Sabine Hemmer B427 February 2012
Shockley-Ramo TheoremQ(t)=-qmiddotΦ
w(r(t))
BackupPhase II detectors
Ew(r)=-nablaΦ
Sabine Hemmer B527 February 2012
Backup Background reduction
Key issue Low background rate (Phase I 110 HdM)
sensitivitysimϵsdotasdotradic MsdottbΔ E
Possible backgrounds External
γ from Th and U chain neutrons from spallation μ from cosmic rays
Internal cosmogenic 60Co (T
12=53y)
cosmogenic 68Ge (T12
=271d)
Radioactive surface contamination
Sabine Hemmer B627 February 2012
before MS (059 kgy)
after MS (037 kgy)
Backup Play with the electric fieldAdd a mini-shroud (MS)
70 cm
Shroud (already installed to prevent 222Rn concentration)
+ +- -+ +- -
MSV
S-MS=+700V (019 kgy)
VS-MS
=-400V (037 kgy)
Sabine Hemmer B727 February 2012
Backup Muon induced events
dataMC
Spectrum of muon-induced events in Germanium (209 kgy during commissioning)
Estimate of muon veto efficiency for events causing a signal in Ge ε = 987Estimate of muon-induced background at Q
ββ B
μ lt 20middot10-4 countskeVmiddotkgmiddoty
middot
Sabine Hemmer B827 February 2012
Operation of Phase II proto-type detector in LarGeCombining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Also successful read out scintillation light with fibers coupled to SiPMs
Sabine Hemmer B927 February 2012
Backup RampD liquid argon instrumentation
- Pagina 1
- Pagina 2
- Pagina 3
- Pagina 4
- Pagina 5
- Pagina 6
- Pagina 7
- Pagina 8
- Pagina 9
- Pagina 10
- Pagina 11
- Pagina 12
- Pagina 13
- Pagina 14
- Pagina 15
- Pagina 16
- Pagina 17
- Pagina 18
- Pagina 19
- Pagina 20
- Pagina 21
- Pagina 22
- Pagina 23
- Pagina 24
- Pagina 25
- Pagina 26
- Pagina 27
- Pagina 28
-
![Page 11: Searching for Double Beta Decay with GERDA · [1] Eur. Phys. J. A12, 147-154 (2001) [2] Phys. Rev. D 65, 092007 (2002) Claim of signal from parts of HdM: T 1/2 (76Ge) = (0.69 –](https://reader034.fdocuments.us/reader034/viewer/2022050212/5f5e4aaf5c00cd76d9057fc3/html5/thumbnails/11.jpg)
Start of Phase I6 November 2011 Start of Phase I
All 8 enrGe + 4 natGe detectors deployed in GERDA(2 enrGe detectors presently not used for analysis)
natGe 197 kgmiddoty (76 kg)
enrGe 380 kgmiddoty (146 kg)
Sabine Hemmer 1027 February 2012
Energy spectrum
(Unexpected) Background from Argon
101 Bqkg T12
=269 y
pure β emitter Q-value=565keV rarr below region of interest
39Ar
Sabine Hemmer 1127 February 2012
42ArGERDA proposal 42ArnatAr lt 3 x 10-21 (Barabash et al 2002)GERDA measurement Count rate at 1525keV ~ 2 times expectation
Field-free configuration
Region of Interest
middot
Background rate in ROI (Qββ
plusmn100 keV blinded window excluded) enrGe 0017+0009
-0005 counts(keVmiddotkgmiddoty)
natGe 0049+0015-0013
counts(keVmiddotkgmiddoty) most likely a combination of ThU 42K degraded α cosmogenic isotopes factor ~10 lower than previous experiments (HdM IGEX) no pulse shape analysis applied yet
ROI
blinded
ROI
blinded
Sabine Hemmer 1227 February 2012
2νββ
middot
39Ar 101 Bqkg from WARP [NIM A574 83-88 (2007)]
76Ge T12
(2νββ)=174middot1021y from HdM
[NIM A513 596-621 (2003)]
42K homogeneously distributed decays in LAr (normalized to peak)
40K simulated decays in detector holders (normalized to peak)
Sum of MC contributionsData
Sabine Hemmer 1327 February 2012
Phase II detectorscu
rren
t
time [ns]
ββ decay
ACCEPT
γ ray background REJECT
REJECT42K β UTh chain αs
Peculiar pulses
0νββ-like
90 11
γ-bgd
A
A
Sabine Hemmer 1427 February 2012
BEGe production
Sabine Hemmer 1527 February 2012
Crystal pulling at Canberra Oakridge TN USA
BEGe detector diode production Olen BE
BEGe acceptance tests Hades BE
ONGOING ONGOING
ONGOING
First spectra
RampD liquid argon instrumentation
photons
Liquid argon
Detection of coincident liquid argon scintillation
light to discriminate background
LarGe Low-background test facility at LNGS
Sabine Hemmer 1627 February 2012
Also other designs investigated rarr avoid additional background
Combining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Summary
GERDA Phase I started in November 2011 Unexpectedly high contribution from 42Ar decays Background in ROI lower than in previous experiments (~ factor 10)
but slightly higher than design goal 2νββ spectrum well reproduced by MC (taking into account
contributions from 39Ar 42Ar and 40K) Phase II detector production and RampD on LAr scintillation light
readout ongoing
Sabine Hemmer 1727 February 2012
The GERDA collaboration
Sabine Hemmer 1827 February 2012
BackupHdM claim
Nov 1990 - May 2003 717 kg year Bgd 011 counts (keVkgy) 2875 plusmn 687 events (bgd~60) 42σ evidence for 0νββ
(069 ndash 418)middot1025 y (3 σ) Best fit 119middot1025 y
mββ
= (024-058) eV
best fit 044 eV
Note statistical significance depends on background model
Phys Lett B 586 198-212 (2004)
Comparison IGEX
D Gonzalez et al NPB (Proc Suppl) 87 (2000) 278
Sabine Hemmer B127 February 2012
Backup α events
Sabine Hemmer B227 February 2012
Backup calibration
Sabine Hemmer B327 February 2012
BackupNeutrino properties
What we know m
22-m
12=Δm
sun2
m2
2-m1
2=Δmatm
2
θ12
=θsun
θ23
=θatm
θ
13
What we do not know Absolute mass scale Mass hierarchy Phases (δ
13 α
21 α
31)
Nature of the neutrino mass (Dirac or Majorana)
Sabine Hemmer B427 February 2012
Shockley-Ramo TheoremQ(t)=-qmiddotΦ
w(r(t))
BackupPhase II detectors
Ew(r)=-nablaΦ
Sabine Hemmer B527 February 2012
Backup Background reduction
Key issue Low background rate (Phase I 110 HdM)
sensitivitysimϵsdotasdotradic MsdottbΔ E
Possible backgrounds External
γ from Th and U chain neutrons from spallation μ from cosmic rays
Internal cosmogenic 60Co (T
12=53y)
cosmogenic 68Ge (T12
=271d)
Radioactive surface contamination
Sabine Hemmer B627 February 2012
before MS (059 kgy)
after MS (037 kgy)
Backup Play with the electric fieldAdd a mini-shroud (MS)
70 cm
Shroud (already installed to prevent 222Rn concentration)
+ +- -+ +- -
MSV
S-MS=+700V (019 kgy)
VS-MS
=-400V (037 kgy)
Sabine Hemmer B727 February 2012
Backup Muon induced events
dataMC
Spectrum of muon-induced events in Germanium (209 kgy during commissioning)
Estimate of muon veto efficiency for events causing a signal in Ge ε = 987Estimate of muon-induced background at Q
ββ B
μ lt 20middot10-4 countskeVmiddotkgmiddoty
middot
Sabine Hemmer B827 February 2012
Operation of Phase II proto-type detector in LarGeCombining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Also successful read out scintillation light with fibers coupled to SiPMs
Sabine Hemmer B927 February 2012
Backup RampD liquid argon instrumentation
- Pagina 1
- Pagina 2
- Pagina 3
- Pagina 4
- Pagina 5
- Pagina 6
- Pagina 7
- Pagina 8
- Pagina 9
- Pagina 10
- Pagina 11
- Pagina 12
- Pagina 13
- Pagina 14
- Pagina 15
- Pagina 16
- Pagina 17
- Pagina 18
- Pagina 19
- Pagina 20
- Pagina 21
- Pagina 22
- Pagina 23
- Pagina 24
- Pagina 25
- Pagina 26
- Pagina 27
- Pagina 28
-
![Page 12: Searching for Double Beta Decay with GERDA · [1] Eur. Phys. J. A12, 147-154 (2001) [2] Phys. Rev. D 65, 092007 (2002) Claim of signal from parts of HdM: T 1/2 (76Ge) = (0.69 –](https://reader034.fdocuments.us/reader034/viewer/2022050212/5f5e4aaf5c00cd76d9057fc3/html5/thumbnails/12.jpg)
(Unexpected) Background from Argon
101 Bqkg T12
=269 y
pure β emitter Q-value=565keV rarr below region of interest
39Ar
Sabine Hemmer 1127 February 2012
42ArGERDA proposal 42ArnatAr lt 3 x 10-21 (Barabash et al 2002)GERDA measurement Count rate at 1525keV ~ 2 times expectation
Field-free configuration
Region of Interest
middot
Background rate in ROI (Qββ
plusmn100 keV blinded window excluded) enrGe 0017+0009
-0005 counts(keVmiddotkgmiddoty)
natGe 0049+0015-0013
counts(keVmiddotkgmiddoty) most likely a combination of ThU 42K degraded α cosmogenic isotopes factor ~10 lower than previous experiments (HdM IGEX) no pulse shape analysis applied yet
ROI
blinded
ROI
blinded
Sabine Hemmer 1227 February 2012
2νββ
middot
39Ar 101 Bqkg from WARP [NIM A574 83-88 (2007)]
76Ge T12
(2νββ)=174middot1021y from HdM
[NIM A513 596-621 (2003)]
42K homogeneously distributed decays in LAr (normalized to peak)
40K simulated decays in detector holders (normalized to peak)
Sum of MC contributionsData
Sabine Hemmer 1327 February 2012
Phase II detectorscu
rren
t
time [ns]
ββ decay
ACCEPT
γ ray background REJECT
REJECT42K β UTh chain αs
Peculiar pulses
0νββ-like
90 11
γ-bgd
A
A
Sabine Hemmer 1427 February 2012
BEGe production
Sabine Hemmer 1527 February 2012
Crystal pulling at Canberra Oakridge TN USA
BEGe detector diode production Olen BE
BEGe acceptance tests Hades BE
ONGOING ONGOING
ONGOING
First spectra
RampD liquid argon instrumentation
photons
Liquid argon
Detection of coincident liquid argon scintillation
light to discriminate background
LarGe Low-background test facility at LNGS
Sabine Hemmer 1627 February 2012
Also other designs investigated rarr avoid additional background
Combining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Summary
GERDA Phase I started in November 2011 Unexpectedly high contribution from 42Ar decays Background in ROI lower than in previous experiments (~ factor 10)
but slightly higher than design goal 2νββ spectrum well reproduced by MC (taking into account
contributions from 39Ar 42Ar and 40K) Phase II detector production and RampD on LAr scintillation light
readout ongoing
Sabine Hemmer 1727 February 2012
The GERDA collaboration
Sabine Hemmer 1827 February 2012
BackupHdM claim
Nov 1990 - May 2003 717 kg year Bgd 011 counts (keVkgy) 2875 plusmn 687 events (bgd~60) 42σ evidence for 0νββ
(069 ndash 418)middot1025 y (3 σ) Best fit 119middot1025 y
mββ
= (024-058) eV
best fit 044 eV
Note statistical significance depends on background model
Phys Lett B 586 198-212 (2004)
Comparison IGEX
D Gonzalez et al NPB (Proc Suppl) 87 (2000) 278
Sabine Hemmer B127 February 2012
Backup α events
Sabine Hemmer B227 February 2012
Backup calibration
Sabine Hemmer B327 February 2012
BackupNeutrino properties
What we know m
22-m
12=Δm
sun2
m2
2-m1
2=Δmatm
2
θ12
=θsun
θ23
=θatm
θ
13
What we do not know Absolute mass scale Mass hierarchy Phases (δ
13 α
21 α
31)
Nature of the neutrino mass (Dirac or Majorana)
Sabine Hemmer B427 February 2012
Shockley-Ramo TheoremQ(t)=-qmiddotΦ
w(r(t))
BackupPhase II detectors
Ew(r)=-nablaΦ
Sabine Hemmer B527 February 2012
Backup Background reduction
Key issue Low background rate (Phase I 110 HdM)
sensitivitysimϵsdotasdotradic MsdottbΔ E
Possible backgrounds External
γ from Th and U chain neutrons from spallation μ from cosmic rays
Internal cosmogenic 60Co (T
12=53y)
cosmogenic 68Ge (T12
=271d)
Radioactive surface contamination
Sabine Hemmer B627 February 2012
before MS (059 kgy)
after MS (037 kgy)
Backup Play with the electric fieldAdd a mini-shroud (MS)
70 cm
Shroud (already installed to prevent 222Rn concentration)
+ +- -+ +- -
MSV
S-MS=+700V (019 kgy)
VS-MS
=-400V (037 kgy)
Sabine Hemmer B727 February 2012
Backup Muon induced events
dataMC
Spectrum of muon-induced events in Germanium (209 kgy during commissioning)
Estimate of muon veto efficiency for events causing a signal in Ge ε = 987Estimate of muon-induced background at Q
ββ B
μ lt 20middot10-4 countskeVmiddotkgmiddoty
middot
Sabine Hemmer B827 February 2012
Operation of Phase II proto-type detector in LarGeCombining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Also successful read out scintillation light with fibers coupled to SiPMs
Sabine Hemmer B927 February 2012
Backup RampD liquid argon instrumentation
- Pagina 1
- Pagina 2
- Pagina 3
- Pagina 4
- Pagina 5
- Pagina 6
- Pagina 7
- Pagina 8
- Pagina 9
- Pagina 10
- Pagina 11
- Pagina 12
- Pagina 13
- Pagina 14
- Pagina 15
- Pagina 16
- Pagina 17
- Pagina 18
- Pagina 19
- Pagina 20
- Pagina 21
- Pagina 22
- Pagina 23
- Pagina 24
- Pagina 25
- Pagina 26
- Pagina 27
- Pagina 28
-
![Page 13: Searching for Double Beta Decay with GERDA · [1] Eur. Phys. J. A12, 147-154 (2001) [2] Phys. Rev. D 65, 092007 (2002) Claim of signal from parts of HdM: T 1/2 (76Ge) = (0.69 –](https://reader034.fdocuments.us/reader034/viewer/2022050212/5f5e4aaf5c00cd76d9057fc3/html5/thumbnails/13.jpg)
Region of Interest
middot
Background rate in ROI (Qββ
plusmn100 keV blinded window excluded) enrGe 0017+0009
-0005 counts(keVmiddotkgmiddoty)
natGe 0049+0015-0013
counts(keVmiddotkgmiddoty) most likely a combination of ThU 42K degraded α cosmogenic isotopes factor ~10 lower than previous experiments (HdM IGEX) no pulse shape analysis applied yet
ROI
blinded
ROI
blinded
Sabine Hemmer 1227 February 2012
2νββ
middot
39Ar 101 Bqkg from WARP [NIM A574 83-88 (2007)]
76Ge T12
(2νββ)=174middot1021y from HdM
[NIM A513 596-621 (2003)]
42K homogeneously distributed decays in LAr (normalized to peak)
40K simulated decays in detector holders (normalized to peak)
Sum of MC contributionsData
Sabine Hemmer 1327 February 2012
Phase II detectorscu
rren
t
time [ns]
ββ decay
ACCEPT
γ ray background REJECT
REJECT42K β UTh chain αs
Peculiar pulses
0νββ-like
90 11
γ-bgd
A
A
Sabine Hemmer 1427 February 2012
BEGe production
Sabine Hemmer 1527 February 2012
Crystal pulling at Canberra Oakridge TN USA
BEGe detector diode production Olen BE
BEGe acceptance tests Hades BE
ONGOING ONGOING
ONGOING
First spectra
RampD liquid argon instrumentation
photons
Liquid argon
Detection of coincident liquid argon scintillation
light to discriminate background
LarGe Low-background test facility at LNGS
Sabine Hemmer 1627 February 2012
Also other designs investigated rarr avoid additional background
Combining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Summary
GERDA Phase I started in November 2011 Unexpectedly high contribution from 42Ar decays Background in ROI lower than in previous experiments (~ factor 10)
but slightly higher than design goal 2νββ spectrum well reproduced by MC (taking into account
contributions from 39Ar 42Ar and 40K) Phase II detector production and RampD on LAr scintillation light
readout ongoing
Sabine Hemmer 1727 February 2012
The GERDA collaboration
Sabine Hemmer 1827 February 2012
BackupHdM claim
Nov 1990 - May 2003 717 kg year Bgd 011 counts (keVkgy) 2875 plusmn 687 events (bgd~60) 42σ evidence for 0νββ
(069 ndash 418)middot1025 y (3 σ) Best fit 119middot1025 y
mββ
= (024-058) eV
best fit 044 eV
Note statistical significance depends on background model
Phys Lett B 586 198-212 (2004)
Comparison IGEX
D Gonzalez et al NPB (Proc Suppl) 87 (2000) 278
Sabine Hemmer B127 February 2012
Backup α events
Sabine Hemmer B227 February 2012
Backup calibration
Sabine Hemmer B327 February 2012
BackupNeutrino properties
What we know m
22-m
12=Δm
sun2
m2
2-m1
2=Δmatm
2
θ12
=θsun
θ23
=θatm
θ
13
What we do not know Absolute mass scale Mass hierarchy Phases (δ
13 α
21 α
31)
Nature of the neutrino mass (Dirac or Majorana)
Sabine Hemmer B427 February 2012
Shockley-Ramo TheoremQ(t)=-qmiddotΦ
w(r(t))
BackupPhase II detectors
Ew(r)=-nablaΦ
Sabine Hemmer B527 February 2012
Backup Background reduction
Key issue Low background rate (Phase I 110 HdM)
sensitivitysimϵsdotasdotradic MsdottbΔ E
Possible backgrounds External
γ from Th and U chain neutrons from spallation μ from cosmic rays
Internal cosmogenic 60Co (T
12=53y)
cosmogenic 68Ge (T12
=271d)
Radioactive surface contamination
Sabine Hemmer B627 February 2012
before MS (059 kgy)
after MS (037 kgy)
Backup Play with the electric fieldAdd a mini-shroud (MS)
70 cm
Shroud (already installed to prevent 222Rn concentration)
+ +- -+ +- -
MSV
S-MS=+700V (019 kgy)
VS-MS
=-400V (037 kgy)
Sabine Hemmer B727 February 2012
Backup Muon induced events
dataMC
Spectrum of muon-induced events in Germanium (209 kgy during commissioning)
Estimate of muon veto efficiency for events causing a signal in Ge ε = 987Estimate of muon-induced background at Q
ββ B
μ lt 20middot10-4 countskeVmiddotkgmiddoty
middot
Sabine Hemmer B827 February 2012
Operation of Phase II proto-type detector in LarGeCombining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Also successful read out scintillation light with fibers coupled to SiPMs
Sabine Hemmer B927 February 2012
Backup RampD liquid argon instrumentation
- Pagina 1
- Pagina 2
- Pagina 3
- Pagina 4
- Pagina 5
- Pagina 6
- Pagina 7
- Pagina 8
- Pagina 9
- Pagina 10
- Pagina 11
- Pagina 12
- Pagina 13
- Pagina 14
- Pagina 15
- Pagina 16
- Pagina 17
- Pagina 18
- Pagina 19
- Pagina 20
- Pagina 21
- Pagina 22
- Pagina 23
- Pagina 24
- Pagina 25
- Pagina 26
- Pagina 27
- Pagina 28
-
![Page 14: Searching for Double Beta Decay with GERDA · [1] Eur. Phys. J. A12, 147-154 (2001) [2] Phys. Rev. D 65, 092007 (2002) Claim of signal from parts of HdM: T 1/2 (76Ge) = (0.69 –](https://reader034.fdocuments.us/reader034/viewer/2022050212/5f5e4aaf5c00cd76d9057fc3/html5/thumbnails/14.jpg)
2νββ
middot
39Ar 101 Bqkg from WARP [NIM A574 83-88 (2007)]
76Ge T12
(2νββ)=174middot1021y from HdM
[NIM A513 596-621 (2003)]
42K homogeneously distributed decays in LAr (normalized to peak)
40K simulated decays in detector holders (normalized to peak)
Sum of MC contributionsData
Sabine Hemmer 1327 February 2012
Phase II detectorscu
rren
t
time [ns]
ββ decay
ACCEPT
γ ray background REJECT
REJECT42K β UTh chain αs
Peculiar pulses
0νββ-like
90 11
γ-bgd
A
A
Sabine Hemmer 1427 February 2012
BEGe production
Sabine Hemmer 1527 February 2012
Crystal pulling at Canberra Oakridge TN USA
BEGe detector diode production Olen BE
BEGe acceptance tests Hades BE
ONGOING ONGOING
ONGOING
First spectra
RampD liquid argon instrumentation
photons
Liquid argon
Detection of coincident liquid argon scintillation
light to discriminate background
LarGe Low-background test facility at LNGS
Sabine Hemmer 1627 February 2012
Also other designs investigated rarr avoid additional background
Combining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Summary
GERDA Phase I started in November 2011 Unexpectedly high contribution from 42Ar decays Background in ROI lower than in previous experiments (~ factor 10)
but slightly higher than design goal 2νββ spectrum well reproduced by MC (taking into account
contributions from 39Ar 42Ar and 40K) Phase II detector production and RampD on LAr scintillation light
readout ongoing
Sabine Hemmer 1727 February 2012
The GERDA collaboration
Sabine Hemmer 1827 February 2012
BackupHdM claim
Nov 1990 - May 2003 717 kg year Bgd 011 counts (keVkgy) 2875 plusmn 687 events (bgd~60) 42σ evidence for 0νββ
(069 ndash 418)middot1025 y (3 σ) Best fit 119middot1025 y
mββ
= (024-058) eV
best fit 044 eV
Note statistical significance depends on background model
Phys Lett B 586 198-212 (2004)
Comparison IGEX
D Gonzalez et al NPB (Proc Suppl) 87 (2000) 278
Sabine Hemmer B127 February 2012
Backup α events
Sabine Hemmer B227 February 2012
Backup calibration
Sabine Hemmer B327 February 2012
BackupNeutrino properties
What we know m
22-m
12=Δm
sun2
m2
2-m1
2=Δmatm
2
θ12
=θsun
θ23
=θatm
θ
13
What we do not know Absolute mass scale Mass hierarchy Phases (δ
13 α
21 α
31)
Nature of the neutrino mass (Dirac or Majorana)
Sabine Hemmer B427 February 2012
Shockley-Ramo TheoremQ(t)=-qmiddotΦ
w(r(t))
BackupPhase II detectors
Ew(r)=-nablaΦ
Sabine Hemmer B527 February 2012
Backup Background reduction
Key issue Low background rate (Phase I 110 HdM)
sensitivitysimϵsdotasdotradic MsdottbΔ E
Possible backgrounds External
γ from Th and U chain neutrons from spallation μ from cosmic rays
Internal cosmogenic 60Co (T
12=53y)
cosmogenic 68Ge (T12
=271d)
Radioactive surface contamination
Sabine Hemmer B627 February 2012
before MS (059 kgy)
after MS (037 kgy)
Backup Play with the electric fieldAdd a mini-shroud (MS)
70 cm
Shroud (already installed to prevent 222Rn concentration)
+ +- -+ +- -
MSV
S-MS=+700V (019 kgy)
VS-MS
=-400V (037 kgy)
Sabine Hemmer B727 February 2012
Backup Muon induced events
dataMC
Spectrum of muon-induced events in Germanium (209 kgy during commissioning)
Estimate of muon veto efficiency for events causing a signal in Ge ε = 987Estimate of muon-induced background at Q
ββ B
μ lt 20middot10-4 countskeVmiddotkgmiddoty
middot
Sabine Hemmer B827 February 2012
Operation of Phase II proto-type detector in LarGeCombining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Also successful read out scintillation light with fibers coupled to SiPMs
Sabine Hemmer B927 February 2012
Backup RampD liquid argon instrumentation
- Pagina 1
- Pagina 2
- Pagina 3
- Pagina 4
- Pagina 5
- Pagina 6
- Pagina 7
- Pagina 8
- Pagina 9
- Pagina 10
- Pagina 11
- Pagina 12
- Pagina 13
- Pagina 14
- Pagina 15
- Pagina 16
- Pagina 17
- Pagina 18
- Pagina 19
- Pagina 20
- Pagina 21
- Pagina 22
- Pagina 23
- Pagina 24
- Pagina 25
- Pagina 26
- Pagina 27
- Pagina 28
-
![Page 15: Searching for Double Beta Decay with GERDA · [1] Eur. Phys. J. A12, 147-154 (2001) [2] Phys. Rev. D 65, 092007 (2002) Claim of signal from parts of HdM: T 1/2 (76Ge) = (0.69 –](https://reader034.fdocuments.us/reader034/viewer/2022050212/5f5e4aaf5c00cd76d9057fc3/html5/thumbnails/15.jpg)
Phase II detectorscu
rren
t
time [ns]
ββ decay
ACCEPT
γ ray background REJECT
REJECT42K β UTh chain αs
Peculiar pulses
0νββ-like
90 11
γ-bgd
A
A
Sabine Hemmer 1427 February 2012
BEGe production
Sabine Hemmer 1527 February 2012
Crystal pulling at Canberra Oakridge TN USA
BEGe detector diode production Olen BE
BEGe acceptance tests Hades BE
ONGOING ONGOING
ONGOING
First spectra
RampD liquid argon instrumentation
photons
Liquid argon
Detection of coincident liquid argon scintillation
light to discriminate background
LarGe Low-background test facility at LNGS
Sabine Hemmer 1627 February 2012
Also other designs investigated rarr avoid additional background
Combining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Summary
GERDA Phase I started in November 2011 Unexpectedly high contribution from 42Ar decays Background in ROI lower than in previous experiments (~ factor 10)
but slightly higher than design goal 2νββ spectrum well reproduced by MC (taking into account
contributions from 39Ar 42Ar and 40K) Phase II detector production and RampD on LAr scintillation light
readout ongoing
Sabine Hemmer 1727 February 2012
The GERDA collaboration
Sabine Hemmer 1827 February 2012
BackupHdM claim
Nov 1990 - May 2003 717 kg year Bgd 011 counts (keVkgy) 2875 plusmn 687 events (bgd~60) 42σ evidence for 0νββ
(069 ndash 418)middot1025 y (3 σ) Best fit 119middot1025 y
mββ
= (024-058) eV
best fit 044 eV
Note statistical significance depends on background model
Phys Lett B 586 198-212 (2004)
Comparison IGEX
D Gonzalez et al NPB (Proc Suppl) 87 (2000) 278
Sabine Hemmer B127 February 2012
Backup α events
Sabine Hemmer B227 February 2012
Backup calibration
Sabine Hemmer B327 February 2012
BackupNeutrino properties
What we know m
22-m
12=Δm
sun2
m2
2-m1
2=Δmatm
2
θ12
=θsun
θ23
=θatm
θ
13
What we do not know Absolute mass scale Mass hierarchy Phases (δ
13 α
21 α
31)
Nature of the neutrino mass (Dirac or Majorana)
Sabine Hemmer B427 February 2012
Shockley-Ramo TheoremQ(t)=-qmiddotΦ
w(r(t))
BackupPhase II detectors
Ew(r)=-nablaΦ
Sabine Hemmer B527 February 2012
Backup Background reduction
Key issue Low background rate (Phase I 110 HdM)
sensitivitysimϵsdotasdotradic MsdottbΔ E
Possible backgrounds External
γ from Th and U chain neutrons from spallation μ from cosmic rays
Internal cosmogenic 60Co (T
12=53y)
cosmogenic 68Ge (T12
=271d)
Radioactive surface contamination
Sabine Hemmer B627 February 2012
before MS (059 kgy)
after MS (037 kgy)
Backup Play with the electric fieldAdd a mini-shroud (MS)
70 cm
Shroud (already installed to prevent 222Rn concentration)
+ +- -+ +- -
MSV
S-MS=+700V (019 kgy)
VS-MS
=-400V (037 kgy)
Sabine Hemmer B727 February 2012
Backup Muon induced events
dataMC
Spectrum of muon-induced events in Germanium (209 kgy during commissioning)
Estimate of muon veto efficiency for events causing a signal in Ge ε = 987Estimate of muon-induced background at Q
ββ B
μ lt 20middot10-4 countskeVmiddotkgmiddoty
middot
Sabine Hemmer B827 February 2012
Operation of Phase II proto-type detector in LarGeCombining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Also successful read out scintillation light with fibers coupled to SiPMs
Sabine Hemmer B927 February 2012
Backup RampD liquid argon instrumentation
- Pagina 1
- Pagina 2
- Pagina 3
- Pagina 4
- Pagina 5
- Pagina 6
- Pagina 7
- Pagina 8
- Pagina 9
- Pagina 10
- Pagina 11
- Pagina 12
- Pagina 13
- Pagina 14
- Pagina 15
- Pagina 16
- Pagina 17
- Pagina 18
- Pagina 19
- Pagina 20
- Pagina 21
- Pagina 22
- Pagina 23
- Pagina 24
- Pagina 25
- Pagina 26
- Pagina 27
- Pagina 28
-
![Page 16: Searching for Double Beta Decay with GERDA · [1] Eur. Phys. J. A12, 147-154 (2001) [2] Phys. Rev. D 65, 092007 (2002) Claim of signal from parts of HdM: T 1/2 (76Ge) = (0.69 –](https://reader034.fdocuments.us/reader034/viewer/2022050212/5f5e4aaf5c00cd76d9057fc3/html5/thumbnails/16.jpg)
BEGe production
Sabine Hemmer 1527 February 2012
Crystal pulling at Canberra Oakridge TN USA
BEGe detector diode production Olen BE
BEGe acceptance tests Hades BE
ONGOING ONGOING
ONGOING
First spectra
RampD liquid argon instrumentation
photons
Liquid argon
Detection of coincident liquid argon scintillation
light to discriminate background
LarGe Low-background test facility at LNGS
Sabine Hemmer 1627 February 2012
Also other designs investigated rarr avoid additional background
Combining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Summary
GERDA Phase I started in November 2011 Unexpectedly high contribution from 42Ar decays Background in ROI lower than in previous experiments (~ factor 10)
but slightly higher than design goal 2νββ spectrum well reproduced by MC (taking into account
contributions from 39Ar 42Ar and 40K) Phase II detector production and RampD on LAr scintillation light
readout ongoing
Sabine Hemmer 1727 February 2012
The GERDA collaboration
Sabine Hemmer 1827 February 2012
BackupHdM claim
Nov 1990 - May 2003 717 kg year Bgd 011 counts (keVkgy) 2875 plusmn 687 events (bgd~60) 42σ evidence for 0νββ
(069 ndash 418)middot1025 y (3 σ) Best fit 119middot1025 y
mββ
= (024-058) eV
best fit 044 eV
Note statistical significance depends on background model
Phys Lett B 586 198-212 (2004)
Comparison IGEX
D Gonzalez et al NPB (Proc Suppl) 87 (2000) 278
Sabine Hemmer B127 February 2012
Backup α events
Sabine Hemmer B227 February 2012
Backup calibration
Sabine Hemmer B327 February 2012
BackupNeutrino properties
What we know m
22-m
12=Δm
sun2
m2
2-m1
2=Δmatm
2
θ12
=θsun
θ23
=θatm
θ
13
What we do not know Absolute mass scale Mass hierarchy Phases (δ
13 α
21 α
31)
Nature of the neutrino mass (Dirac or Majorana)
Sabine Hemmer B427 February 2012
Shockley-Ramo TheoremQ(t)=-qmiddotΦ
w(r(t))
BackupPhase II detectors
Ew(r)=-nablaΦ
Sabine Hemmer B527 February 2012
Backup Background reduction
Key issue Low background rate (Phase I 110 HdM)
sensitivitysimϵsdotasdotradic MsdottbΔ E
Possible backgrounds External
γ from Th and U chain neutrons from spallation μ from cosmic rays
Internal cosmogenic 60Co (T
12=53y)
cosmogenic 68Ge (T12
=271d)
Radioactive surface contamination
Sabine Hemmer B627 February 2012
before MS (059 kgy)
after MS (037 kgy)
Backup Play with the electric fieldAdd a mini-shroud (MS)
70 cm
Shroud (already installed to prevent 222Rn concentration)
+ +- -+ +- -
MSV
S-MS=+700V (019 kgy)
VS-MS
=-400V (037 kgy)
Sabine Hemmer B727 February 2012
Backup Muon induced events
dataMC
Spectrum of muon-induced events in Germanium (209 kgy during commissioning)
Estimate of muon veto efficiency for events causing a signal in Ge ε = 987Estimate of muon-induced background at Q
ββ B
μ lt 20middot10-4 countskeVmiddotkgmiddoty
middot
Sabine Hemmer B827 February 2012
Operation of Phase II proto-type detector in LarGeCombining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Also successful read out scintillation light with fibers coupled to SiPMs
Sabine Hemmer B927 February 2012
Backup RampD liquid argon instrumentation
- Pagina 1
- Pagina 2
- Pagina 3
- Pagina 4
- Pagina 5
- Pagina 6
- Pagina 7
- Pagina 8
- Pagina 9
- Pagina 10
- Pagina 11
- Pagina 12
- Pagina 13
- Pagina 14
- Pagina 15
- Pagina 16
- Pagina 17
- Pagina 18
- Pagina 19
- Pagina 20
- Pagina 21
- Pagina 22
- Pagina 23
- Pagina 24
- Pagina 25
- Pagina 26
- Pagina 27
- Pagina 28
-
![Page 17: Searching for Double Beta Decay with GERDA · [1] Eur. Phys. J. A12, 147-154 (2001) [2] Phys. Rev. D 65, 092007 (2002) Claim of signal from parts of HdM: T 1/2 (76Ge) = (0.69 –](https://reader034.fdocuments.us/reader034/viewer/2022050212/5f5e4aaf5c00cd76d9057fc3/html5/thumbnails/17.jpg)
RampD liquid argon instrumentation
photons
Liquid argon
Detection of coincident liquid argon scintillation
light to discriminate background
LarGe Low-background test facility at LNGS
Sabine Hemmer 1627 February 2012
Also other designs investigated rarr avoid additional background
Combining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Summary
GERDA Phase I started in November 2011 Unexpectedly high contribution from 42Ar decays Background in ROI lower than in previous experiments (~ factor 10)
but slightly higher than design goal 2νββ spectrum well reproduced by MC (taking into account
contributions from 39Ar 42Ar and 40K) Phase II detector production and RampD on LAr scintillation light
readout ongoing
Sabine Hemmer 1727 February 2012
The GERDA collaboration
Sabine Hemmer 1827 February 2012
BackupHdM claim
Nov 1990 - May 2003 717 kg year Bgd 011 counts (keVkgy) 2875 plusmn 687 events (bgd~60) 42σ evidence for 0νββ
(069 ndash 418)middot1025 y (3 σ) Best fit 119middot1025 y
mββ
= (024-058) eV
best fit 044 eV
Note statistical significance depends on background model
Phys Lett B 586 198-212 (2004)
Comparison IGEX
D Gonzalez et al NPB (Proc Suppl) 87 (2000) 278
Sabine Hemmer B127 February 2012
Backup α events
Sabine Hemmer B227 February 2012
Backup calibration
Sabine Hemmer B327 February 2012
BackupNeutrino properties
What we know m
22-m
12=Δm
sun2
m2
2-m1
2=Δmatm
2
θ12
=θsun
θ23
=θatm
θ
13
What we do not know Absolute mass scale Mass hierarchy Phases (δ
13 α
21 α
31)
Nature of the neutrino mass (Dirac or Majorana)
Sabine Hemmer B427 February 2012
Shockley-Ramo TheoremQ(t)=-qmiddotΦ
w(r(t))
BackupPhase II detectors
Ew(r)=-nablaΦ
Sabine Hemmer B527 February 2012
Backup Background reduction
Key issue Low background rate (Phase I 110 HdM)
sensitivitysimϵsdotasdotradic MsdottbΔ E
Possible backgrounds External
γ from Th and U chain neutrons from spallation μ from cosmic rays
Internal cosmogenic 60Co (T
12=53y)
cosmogenic 68Ge (T12
=271d)
Radioactive surface contamination
Sabine Hemmer B627 February 2012
before MS (059 kgy)
after MS (037 kgy)
Backup Play with the electric fieldAdd a mini-shroud (MS)
70 cm
Shroud (already installed to prevent 222Rn concentration)
+ +- -+ +- -
MSV
S-MS=+700V (019 kgy)
VS-MS
=-400V (037 kgy)
Sabine Hemmer B727 February 2012
Backup Muon induced events
dataMC
Spectrum of muon-induced events in Germanium (209 kgy during commissioning)
Estimate of muon veto efficiency for events causing a signal in Ge ε = 987Estimate of muon-induced background at Q
ββ B
μ lt 20middot10-4 countskeVmiddotkgmiddoty
middot
Sabine Hemmer B827 February 2012
Operation of Phase II proto-type detector in LarGeCombining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Also successful read out scintillation light with fibers coupled to SiPMs
Sabine Hemmer B927 February 2012
Backup RampD liquid argon instrumentation
- Pagina 1
- Pagina 2
- Pagina 3
- Pagina 4
- Pagina 5
- Pagina 6
- Pagina 7
- Pagina 8
- Pagina 9
- Pagina 10
- Pagina 11
- Pagina 12
- Pagina 13
- Pagina 14
- Pagina 15
- Pagina 16
- Pagina 17
- Pagina 18
- Pagina 19
- Pagina 20
- Pagina 21
- Pagina 22
- Pagina 23
- Pagina 24
- Pagina 25
- Pagina 26
- Pagina 27
- Pagina 28
-
![Page 18: Searching for Double Beta Decay with GERDA · [1] Eur. Phys. J. A12, 147-154 (2001) [2] Phys. Rev. D 65, 092007 (2002) Claim of signal from parts of HdM: T 1/2 (76Ge) = (0.69 –](https://reader034.fdocuments.us/reader034/viewer/2022050212/5f5e4aaf5c00cd76d9057fc3/html5/thumbnails/18.jpg)
Summary
GERDA Phase I started in November 2011 Unexpectedly high contribution from 42Ar decays Background in ROI lower than in previous experiments (~ factor 10)
but slightly higher than design goal 2νββ spectrum well reproduced by MC (taking into account
contributions from 39Ar 42Ar and 40K) Phase II detector production and RampD on LAr scintillation light
readout ongoing
Sabine Hemmer 1727 February 2012
The GERDA collaboration
Sabine Hemmer 1827 February 2012
BackupHdM claim
Nov 1990 - May 2003 717 kg year Bgd 011 counts (keVkgy) 2875 plusmn 687 events (bgd~60) 42σ evidence for 0νββ
(069 ndash 418)middot1025 y (3 σ) Best fit 119middot1025 y
mββ
= (024-058) eV
best fit 044 eV
Note statistical significance depends on background model
Phys Lett B 586 198-212 (2004)
Comparison IGEX
D Gonzalez et al NPB (Proc Suppl) 87 (2000) 278
Sabine Hemmer B127 February 2012
Backup α events
Sabine Hemmer B227 February 2012
Backup calibration
Sabine Hemmer B327 February 2012
BackupNeutrino properties
What we know m
22-m
12=Δm
sun2
m2
2-m1
2=Δmatm
2
θ12
=θsun
θ23
=θatm
θ
13
What we do not know Absolute mass scale Mass hierarchy Phases (δ
13 α
21 α
31)
Nature of the neutrino mass (Dirac or Majorana)
Sabine Hemmer B427 February 2012
Shockley-Ramo TheoremQ(t)=-qmiddotΦ
w(r(t))
BackupPhase II detectors
Ew(r)=-nablaΦ
Sabine Hemmer B527 February 2012
Backup Background reduction
Key issue Low background rate (Phase I 110 HdM)
sensitivitysimϵsdotasdotradic MsdottbΔ E
Possible backgrounds External
γ from Th and U chain neutrons from spallation μ from cosmic rays
Internal cosmogenic 60Co (T
12=53y)
cosmogenic 68Ge (T12
=271d)
Radioactive surface contamination
Sabine Hemmer B627 February 2012
before MS (059 kgy)
after MS (037 kgy)
Backup Play with the electric fieldAdd a mini-shroud (MS)
70 cm
Shroud (already installed to prevent 222Rn concentration)
+ +- -+ +- -
MSV
S-MS=+700V (019 kgy)
VS-MS
=-400V (037 kgy)
Sabine Hemmer B727 February 2012
Backup Muon induced events
dataMC
Spectrum of muon-induced events in Germanium (209 kgy during commissioning)
Estimate of muon veto efficiency for events causing a signal in Ge ε = 987Estimate of muon-induced background at Q
ββ B
μ lt 20middot10-4 countskeVmiddotkgmiddoty
middot
Sabine Hemmer B827 February 2012
Operation of Phase II proto-type detector in LarGeCombining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Also successful read out scintillation light with fibers coupled to SiPMs
Sabine Hemmer B927 February 2012
Backup RampD liquid argon instrumentation
- Pagina 1
- Pagina 2
- Pagina 3
- Pagina 4
- Pagina 5
- Pagina 6
- Pagina 7
- Pagina 8
- Pagina 9
- Pagina 10
- Pagina 11
- Pagina 12
- Pagina 13
- Pagina 14
- Pagina 15
- Pagina 16
- Pagina 17
- Pagina 18
- Pagina 19
- Pagina 20
- Pagina 21
- Pagina 22
- Pagina 23
- Pagina 24
- Pagina 25
- Pagina 26
- Pagina 27
- Pagina 28
-
![Page 19: Searching for Double Beta Decay with GERDA · [1] Eur. Phys. J. A12, 147-154 (2001) [2] Phys. Rev. D 65, 092007 (2002) Claim of signal from parts of HdM: T 1/2 (76Ge) = (0.69 –](https://reader034.fdocuments.us/reader034/viewer/2022050212/5f5e4aaf5c00cd76d9057fc3/html5/thumbnails/19.jpg)
The GERDA collaboration
Sabine Hemmer 1827 February 2012
BackupHdM claim
Nov 1990 - May 2003 717 kg year Bgd 011 counts (keVkgy) 2875 plusmn 687 events (bgd~60) 42σ evidence for 0νββ
(069 ndash 418)middot1025 y (3 σ) Best fit 119middot1025 y
mββ
= (024-058) eV
best fit 044 eV
Note statistical significance depends on background model
Phys Lett B 586 198-212 (2004)
Comparison IGEX
D Gonzalez et al NPB (Proc Suppl) 87 (2000) 278
Sabine Hemmer B127 February 2012
Backup α events
Sabine Hemmer B227 February 2012
Backup calibration
Sabine Hemmer B327 February 2012
BackupNeutrino properties
What we know m
22-m
12=Δm
sun2
m2
2-m1
2=Δmatm
2
θ12
=θsun
θ23
=θatm
θ
13
What we do not know Absolute mass scale Mass hierarchy Phases (δ
13 α
21 α
31)
Nature of the neutrino mass (Dirac or Majorana)
Sabine Hemmer B427 February 2012
Shockley-Ramo TheoremQ(t)=-qmiddotΦ
w(r(t))
BackupPhase II detectors
Ew(r)=-nablaΦ
Sabine Hemmer B527 February 2012
Backup Background reduction
Key issue Low background rate (Phase I 110 HdM)
sensitivitysimϵsdotasdotradic MsdottbΔ E
Possible backgrounds External
γ from Th and U chain neutrons from spallation μ from cosmic rays
Internal cosmogenic 60Co (T
12=53y)
cosmogenic 68Ge (T12
=271d)
Radioactive surface contamination
Sabine Hemmer B627 February 2012
before MS (059 kgy)
after MS (037 kgy)
Backup Play with the electric fieldAdd a mini-shroud (MS)
70 cm
Shroud (already installed to prevent 222Rn concentration)
+ +- -+ +- -
MSV
S-MS=+700V (019 kgy)
VS-MS
=-400V (037 kgy)
Sabine Hemmer B727 February 2012
Backup Muon induced events
dataMC
Spectrum of muon-induced events in Germanium (209 kgy during commissioning)
Estimate of muon veto efficiency for events causing a signal in Ge ε = 987Estimate of muon-induced background at Q
ββ B
μ lt 20middot10-4 countskeVmiddotkgmiddoty
middot
Sabine Hemmer B827 February 2012
Operation of Phase II proto-type detector in LarGeCombining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Also successful read out scintillation light with fibers coupled to SiPMs
Sabine Hemmer B927 February 2012
Backup RampD liquid argon instrumentation
- Pagina 1
- Pagina 2
- Pagina 3
- Pagina 4
- Pagina 5
- Pagina 6
- Pagina 7
- Pagina 8
- Pagina 9
- Pagina 10
- Pagina 11
- Pagina 12
- Pagina 13
- Pagina 14
- Pagina 15
- Pagina 16
- Pagina 17
- Pagina 18
- Pagina 19
- Pagina 20
- Pagina 21
- Pagina 22
- Pagina 23
- Pagina 24
- Pagina 25
- Pagina 26
- Pagina 27
- Pagina 28
-
![Page 20: Searching for Double Beta Decay with GERDA · [1] Eur. Phys. J. A12, 147-154 (2001) [2] Phys. Rev. D 65, 092007 (2002) Claim of signal from parts of HdM: T 1/2 (76Ge) = (0.69 –](https://reader034.fdocuments.us/reader034/viewer/2022050212/5f5e4aaf5c00cd76d9057fc3/html5/thumbnails/20.jpg)
BackupHdM claim
Nov 1990 - May 2003 717 kg year Bgd 011 counts (keVkgy) 2875 plusmn 687 events (bgd~60) 42σ evidence for 0νββ
(069 ndash 418)middot1025 y (3 σ) Best fit 119middot1025 y
mββ
= (024-058) eV
best fit 044 eV
Note statistical significance depends on background model
Phys Lett B 586 198-212 (2004)
Comparison IGEX
D Gonzalez et al NPB (Proc Suppl) 87 (2000) 278
Sabine Hemmer B127 February 2012
Backup α events
Sabine Hemmer B227 February 2012
Backup calibration
Sabine Hemmer B327 February 2012
BackupNeutrino properties
What we know m
22-m
12=Δm
sun2
m2
2-m1
2=Δmatm
2
θ12
=θsun
θ23
=θatm
θ
13
What we do not know Absolute mass scale Mass hierarchy Phases (δ
13 α
21 α
31)
Nature of the neutrino mass (Dirac or Majorana)
Sabine Hemmer B427 February 2012
Shockley-Ramo TheoremQ(t)=-qmiddotΦ
w(r(t))
BackupPhase II detectors
Ew(r)=-nablaΦ
Sabine Hemmer B527 February 2012
Backup Background reduction
Key issue Low background rate (Phase I 110 HdM)
sensitivitysimϵsdotasdotradic MsdottbΔ E
Possible backgrounds External
γ from Th and U chain neutrons from spallation μ from cosmic rays
Internal cosmogenic 60Co (T
12=53y)
cosmogenic 68Ge (T12
=271d)
Radioactive surface contamination
Sabine Hemmer B627 February 2012
before MS (059 kgy)
after MS (037 kgy)
Backup Play with the electric fieldAdd a mini-shroud (MS)
70 cm
Shroud (already installed to prevent 222Rn concentration)
+ +- -+ +- -
MSV
S-MS=+700V (019 kgy)
VS-MS
=-400V (037 kgy)
Sabine Hemmer B727 February 2012
Backup Muon induced events
dataMC
Spectrum of muon-induced events in Germanium (209 kgy during commissioning)
Estimate of muon veto efficiency for events causing a signal in Ge ε = 987Estimate of muon-induced background at Q
ββ B
μ lt 20middot10-4 countskeVmiddotkgmiddoty
middot
Sabine Hemmer B827 February 2012
Operation of Phase II proto-type detector in LarGeCombining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Also successful read out scintillation light with fibers coupled to SiPMs
Sabine Hemmer B927 February 2012
Backup RampD liquid argon instrumentation
- Pagina 1
- Pagina 2
- Pagina 3
- Pagina 4
- Pagina 5
- Pagina 6
- Pagina 7
- Pagina 8
- Pagina 9
- Pagina 10
- Pagina 11
- Pagina 12
- Pagina 13
- Pagina 14
- Pagina 15
- Pagina 16
- Pagina 17
- Pagina 18
- Pagina 19
- Pagina 20
- Pagina 21
- Pagina 22
- Pagina 23
- Pagina 24
- Pagina 25
- Pagina 26
- Pagina 27
- Pagina 28
-
![Page 21: Searching for Double Beta Decay with GERDA · [1] Eur. Phys. J. A12, 147-154 (2001) [2] Phys. Rev. D 65, 092007 (2002) Claim of signal from parts of HdM: T 1/2 (76Ge) = (0.69 –](https://reader034.fdocuments.us/reader034/viewer/2022050212/5f5e4aaf5c00cd76d9057fc3/html5/thumbnails/21.jpg)
Backup α events
Sabine Hemmer B227 February 2012
Backup calibration
Sabine Hemmer B327 February 2012
BackupNeutrino properties
What we know m
22-m
12=Δm
sun2
m2
2-m1
2=Δmatm
2
θ12
=θsun
θ23
=θatm
θ
13
What we do not know Absolute mass scale Mass hierarchy Phases (δ
13 α
21 α
31)
Nature of the neutrino mass (Dirac or Majorana)
Sabine Hemmer B427 February 2012
Shockley-Ramo TheoremQ(t)=-qmiddotΦ
w(r(t))
BackupPhase II detectors
Ew(r)=-nablaΦ
Sabine Hemmer B527 February 2012
Backup Background reduction
Key issue Low background rate (Phase I 110 HdM)
sensitivitysimϵsdotasdotradic MsdottbΔ E
Possible backgrounds External
γ from Th and U chain neutrons from spallation μ from cosmic rays
Internal cosmogenic 60Co (T
12=53y)
cosmogenic 68Ge (T12
=271d)
Radioactive surface contamination
Sabine Hemmer B627 February 2012
before MS (059 kgy)
after MS (037 kgy)
Backup Play with the electric fieldAdd a mini-shroud (MS)
70 cm
Shroud (already installed to prevent 222Rn concentration)
+ +- -+ +- -
MSV
S-MS=+700V (019 kgy)
VS-MS
=-400V (037 kgy)
Sabine Hemmer B727 February 2012
Backup Muon induced events
dataMC
Spectrum of muon-induced events in Germanium (209 kgy during commissioning)
Estimate of muon veto efficiency for events causing a signal in Ge ε = 987Estimate of muon-induced background at Q
ββ B
μ lt 20middot10-4 countskeVmiddotkgmiddoty
middot
Sabine Hemmer B827 February 2012
Operation of Phase II proto-type detector in LarGeCombining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Also successful read out scintillation light with fibers coupled to SiPMs
Sabine Hemmer B927 February 2012
Backup RampD liquid argon instrumentation
- Pagina 1
- Pagina 2
- Pagina 3
- Pagina 4
- Pagina 5
- Pagina 6
- Pagina 7
- Pagina 8
- Pagina 9
- Pagina 10
- Pagina 11
- Pagina 12
- Pagina 13
- Pagina 14
- Pagina 15
- Pagina 16
- Pagina 17
- Pagina 18
- Pagina 19
- Pagina 20
- Pagina 21
- Pagina 22
- Pagina 23
- Pagina 24
- Pagina 25
- Pagina 26
- Pagina 27
- Pagina 28
-
![Page 22: Searching for Double Beta Decay with GERDA · [1] Eur. Phys. J. A12, 147-154 (2001) [2] Phys. Rev. D 65, 092007 (2002) Claim of signal from parts of HdM: T 1/2 (76Ge) = (0.69 –](https://reader034.fdocuments.us/reader034/viewer/2022050212/5f5e4aaf5c00cd76d9057fc3/html5/thumbnails/22.jpg)
Backup calibration
Sabine Hemmer B327 February 2012
BackupNeutrino properties
What we know m
22-m
12=Δm
sun2
m2
2-m1
2=Δmatm
2
θ12
=θsun
θ23
=θatm
θ
13
What we do not know Absolute mass scale Mass hierarchy Phases (δ
13 α
21 α
31)
Nature of the neutrino mass (Dirac or Majorana)
Sabine Hemmer B427 February 2012
Shockley-Ramo TheoremQ(t)=-qmiddotΦ
w(r(t))
BackupPhase II detectors
Ew(r)=-nablaΦ
Sabine Hemmer B527 February 2012
Backup Background reduction
Key issue Low background rate (Phase I 110 HdM)
sensitivitysimϵsdotasdotradic MsdottbΔ E
Possible backgrounds External
γ from Th and U chain neutrons from spallation μ from cosmic rays
Internal cosmogenic 60Co (T
12=53y)
cosmogenic 68Ge (T12
=271d)
Radioactive surface contamination
Sabine Hemmer B627 February 2012
before MS (059 kgy)
after MS (037 kgy)
Backup Play with the electric fieldAdd a mini-shroud (MS)
70 cm
Shroud (already installed to prevent 222Rn concentration)
+ +- -+ +- -
MSV
S-MS=+700V (019 kgy)
VS-MS
=-400V (037 kgy)
Sabine Hemmer B727 February 2012
Backup Muon induced events
dataMC
Spectrum of muon-induced events in Germanium (209 kgy during commissioning)
Estimate of muon veto efficiency for events causing a signal in Ge ε = 987Estimate of muon-induced background at Q
ββ B
μ lt 20middot10-4 countskeVmiddotkgmiddoty
middot
Sabine Hemmer B827 February 2012
Operation of Phase II proto-type detector in LarGeCombining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Also successful read out scintillation light with fibers coupled to SiPMs
Sabine Hemmer B927 February 2012
Backup RampD liquid argon instrumentation
- Pagina 1
- Pagina 2
- Pagina 3
- Pagina 4
- Pagina 5
- Pagina 6
- Pagina 7
- Pagina 8
- Pagina 9
- Pagina 10
- Pagina 11
- Pagina 12
- Pagina 13
- Pagina 14
- Pagina 15
- Pagina 16
- Pagina 17
- Pagina 18
- Pagina 19
- Pagina 20
- Pagina 21
- Pagina 22
- Pagina 23
- Pagina 24
- Pagina 25
- Pagina 26
- Pagina 27
- Pagina 28
-
![Page 23: Searching for Double Beta Decay with GERDA · [1] Eur. Phys. J. A12, 147-154 (2001) [2] Phys. Rev. D 65, 092007 (2002) Claim of signal from parts of HdM: T 1/2 (76Ge) = (0.69 –](https://reader034.fdocuments.us/reader034/viewer/2022050212/5f5e4aaf5c00cd76d9057fc3/html5/thumbnails/23.jpg)
BackupNeutrino properties
What we know m
22-m
12=Δm
sun2
m2
2-m1
2=Δmatm
2
θ12
=θsun
θ23
=θatm
θ
13
What we do not know Absolute mass scale Mass hierarchy Phases (δ
13 α
21 α
31)
Nature of the neutrino mass (Dirac or Majorana)
Sabine Hemmer B427 February 2012
Shockley-Ramo TheoremQ(t)=-qmiddotΦ
w(r(t))
BackupPhase II detectors
Ew(r)=-nablaΦ
Sabine Hemmer B527 February 2012
Backup Background reduction
Key issue Low background rate (Phase I 110 HdM)
sensitivitysimϵsdotasdotradic MsdottbΔ E
Possible backgrounds External
γ from Th and U chain neutrons from spallation μ from cosmic rays
Internal cosmogenic 60Co (T
12=53y)
cosmogenic 68Ge (T12
=271d)
Radioactive surface contamination
Sabine Hemmer B627 February 2012
before MS (059 kgy)
after MS (037 kgy)
Backup Play with the electric fieldAdd a mini-shroud (MS)
70 cm
Shroud (already installed to prevent 222Rn concentration)
+ +- -+ +- -
MSV
S-MS=+700V (019 kgy)
VS-MS
=-400V (037 kgy)
Sabine Hemmer B727 February 2012
Backup Muon induced events
dataMC
Spectrum of muon-induced events in Germanium (209 kgy during commissioning)
Estimate of muon veto efficiency for events causing a signal in Ge ε = 987Estimate of muon-induced background at Q
ββ B
μ lt 20middot10-4 countskeVmiddotkgmiddoty
middot
Sabine Hemmer B827 February 2012
Operation of Phase II proto-type detector in LarGeCombining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Also successful read out scintillation light with fibers coupled to SiPMs
Sabine Hemmer B927 February 2012
Backup RampD liquid argon instrumentation
- Pagina 1
- Pagina 2
- Pagina 3
- Pagina 4
- Pagina 5
- Pagina 6
- Pagina 7
- Pagina 8
- Pagina 9
- Pagina 10
- Pagina 11
- Pagina 12
- Pagina 13
- Pagina 14
- Pagina 15
- Pagina 16
- Pagina 17
- Pagina 18
- Pagina 19
- Pagina 20
- Pagina 21
- Pagina 22
- Pagina 23
- Pagina 24
- Pagina 25
- Pagina 26
- Pagina 27
- Pagina 28
-
![Page 24: Searching for Double Beta Decay with GERDA · [1] Eur. Phys. J. A12, 147-154 (2001) [2] Phys. Rev. D 65, 092007 (2002) Claim of signal from parts of HdM: T 1/2 (76Ge) = (0.69 –](https://reader034.fdocuments.us/reader034/viewer/2022050212/5f5e4aaf5c00cd76d9057fc3/html5/thumbnails/24.jpg)
Shockley-Ramo TheoremQ(t)=-qmiddotΦ
w(r(t))
BackupPhase II detectors
Ew(r)=-nablaΦ
Sabine Hemmer B527 February 2012
Backup Background reduction
Key issue Low background rate (Phase I 110 HdM)
sensitivitysimϵsdotasdotradic MsdottbΔ E
Possible backgrounds External
γ from Th and U chain neutrons from spallation μ from cosmic rays
Internal cosmogenic 60Co (T
12=53y)
cosmogenic 68Ge (T12
=271d)
Radioactive surface contamination
Sabine Hemmer B627 February 2012
before MS (059 kgy)
after MS (037 kgy)
Backup Play with the electric fieldAdd a mini-shroud (MS)
70 cm
Shroud (already installed to prevent 222Rn concentration)
+ +- -+ +- -
MSV
S-MS=+700V (019 kgy)
VS-MS
=-400V (037 kgy)
Sabine Hemmer B727 February 2012
Backup Muon induced events
dataMC
Spectrum of muon-induced events in Germanium (209 kgy during commissioning)
Estimate of muon veto efficiency for events causing a signal in Ge ε = 987Estimate of muon-induced background at Q
ββ B
μ lt 20middot10-4 countskeVmiddotkgmiddoty
middot
Sabine Hemmer B827 February 2012
Operation of Phase II proto-type detector in LarGeCombining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Also successful read out scintillation light with fibers coupled to SiPMs
Sabine Hemmer B927 February 2012
Backup RampD liquid argon instrumentation
- Pagina 1
- Pagina 2
- Pagina 3
- Pagina 4
- Pagina 5
- Pagina 6
- Pagina 7
- Pagina 8
- Pagina 9
- Pagina 10
- Pagina 11
- Pagina 12
- Pagina 13
- Pagina 14
- Pagina 15
- Pagina 16
- Pagina 17
- Pagina 18
- Pagina 19
- Pagina 20
- Pagina 21
- Pagina 22
- Pagina 23
- Pagina 24
- Pagina 25
- Pagina 26
- Pagina 27
- Pagina 28
-
![Page 25: Searching for Double Beta Decay with GERDA · [1] Eur. Phys. J. A12, 147-154 (2001) [2] Phys. Rev. D 65, 092007 (2002) Claim of signal from parts of HdM: T 1/2 (76Ge) = (0.69 –](https://reader034.fdocuments.us/reader034/viewer/2022050212/5f5e4aaf5c00cd76d9057fc3/html5/thumbnails/25.jpg)
Backup Background reduction
Key issue Low background rate (Phase I 110 HdM)
sensitivitysimϵsdotasdotradic MsdottbΔ E
Possible backgrounds External
γ from Th and U chain neutrons from spallation μ from cosmic rays
Internal cosmogenic 60Co (T
12=53y)
cosmogenic 68Ge (T12
=271d)
Radioactive surface contamination
Sabine Hemmer B627 February 2012
before MS (059 kgy)
after MS (037 kgy)
Backup Play with the electric fieldAdd a mini-shroud (MS)
70 cm
Shroud (already installed to prevent 222Rn concentration)
+ +- -+ +- -
MSV
S-MS=+700V (019 kgy)
VS-MS
=-400V (037 kgy)
Sabine Hemmer B727 February 2012
Backup Muon induced events
dataMC
Spectrum of muon-induced events in Germanium (209 kgy during commissioning)
Estimate of muon veto efficiency for events causing a signal in Ge ε = 987Estimate of muon-induced background at Q
ββ B
μ lt 20middot10-4 countskeVmiddotkgmiddoty
middot
Sabine Hemmer B827 February 2012
Operation of Phase II proto-type detector in LarGeCombining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Also successful read out scintillation light with fibers coupled to SiPMs
Sabine Hemmer B927 February 2012
Backup RampD liquid argon instrumentation
- Pagina 1
- Pagina 2
- Pagina 3
- Pagina 4
- Pagina 5
- Pagina 6
- Pagina 7
- Pagina 8
- Pagina 9
- Pagina 10
- Pagina 11
- Pagina 12
- Pagina 13
- Pagina 14
- Pagina 15
- Pagina 16
- Pagina 17
- Pagina 18
- Pagina 19
- Pagina 20
- Pagina 21
- Pagina 22
- Pagina 23
- Pagina 24
- Pagina 25
- Pagina 26
- Pagina 27
- Pagina 28
-
![Page 26: Searching for Double Beta Decay with GERDA · [1] Eur. Phys. J. A12, 147-154 (2001) [2] Phys. Rev. D 65, 092007 (2002) Claim of signal from parts of HdM: T 1/2 (76Ge) = (0.69 –](https://reader034.fdocuments.us/reader034/viewer/2022050212/5f5e4aaf5c00cd76d9057fc3/html5/thumbnails/26.jpg)
before MS (059 kgy)
after MS (037 kgy)
Backup Play with the electric fieldAdd a mini-shroud (MS)
70 cm
Shroud (already installed to prevent 222Rn concentration)
+ +- -+ +- -
MSV
S-MS=+700V (019 kgy)
VS-MS
=-400V (037 kgy)
Sabine Hemmer B727 February 2012
Backup Muon induced events
dataMC
Spectrum of muon-induced events in Germanium (209 kgy during commissioning)
Estimate of muon veto efficiency for events causing a signal in Ge ε = 987Estimate of muon-induced background at Q
ββ B
μ lt 20middot10-4 countskeVmiddotkgmiddoty
middot
Sabine Hemmer B827 February 2012
Operation of Phase II proto-type detector in LarGeCombining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Also successful read out scintillation light with fibers coupled to SiPMs
Sabine Hemmer B927 February 2012
Backup RampD liquid argon instrumentation
- Pagina 1
- Pagina 2
- Pagina 3
- Pagina 4
- Pagina 5
- Pagina 6
- Pagina 7
- Pagina 8
- Pagina 9
- Pagina 10
- Pagina 11
- Pagina 12
- Pagina 13
- Pagina 14
- Pagina 15
- Pagina 16
- Pagina 17
- Pagina 18
- Pagina 19
- Pagina 20
- Pagina 21
- Pagina 22
- Pagina 23
- Pagina 24
- Pagina 25
- Pagina 26
- Pagina 27
- Pagina 28
-
![Page 27: Searching for Double Beta Decay with GERDA · [1] Eur. Phys. J. A12, 147-154 (2001) [2] Phys. Rev. D 65, 092007 (2002) Claim of signal from parts of HdM: T 1/2 (76Ge) = (0.69 –](https://reader034.fdocuments.us/reader034/viewer/2022050212/5f5e4aaf5c00cd76d9057fc3/html5/thumbnails/27.jpg)
Backup Muon induced events
dataMC
Spectrum of muon-induced events in Germanium (209 kgy during commissioning)
Estimate of muon veto efficiency for events causing a signal in Ge ε = 987Estimate of muon-induced background at Q
ββ B
μ lt 20middot10-4 countskeVmiddotkgmiddoty
middot
Sabine Hemmer B827 February 2012
Operation of Phase II proto-type detector in LarGeCombining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Also successful read out scintillation light with fibers coupled to SiPMs
Sabine Hemmer B927 February 2012
Backup RampD liquid argon instrumentation
- Pagina 1
- Pagina 2
- Pagina 3
- Pagina 4
- Pagina 5
- Pagina 6
- Pagina 7
- Pagina 8
- Pagina 9
- Pagina 10
- Pagina 11
- Pagina 12
- Pagina 13
- Pagina 14
- Pagina 15
- Pagina 16
- Pagina 17
- Pagina 18
- Pagina 19
- Pagina 20
- Pagina 21
- Pagina 22
- Pagina 23
- Pagina 24
- Pagina 25
- Pagina 26
- Pagina 27
- Pagina 28
-
![Page 28: Searching for Double Beta Decay with GERDA · [1] Eur. Phys. J. A12, 147-154 (2001) [2] Phys. Rev. D 65, 092007 (2002) Claim of signal from parts of HdM: T 1/2 (76Ge) = (0.69 –](https://reader034.fdocuments.us/reader034/viewer/2022050212/5f5e4aaf5c00cd76d9057fc3/html5/thumbnails/28.jpg)
Operation of Phase II proto-type detector in LarGeCombining PSD of BEGe detector and LAr veto Measured suppression factor for a 228Th source at Q
ββ ~ 05middot104
Also successful read out scintillation light with fibers coupled to SiPMs
Sabine Hemmer B927 February 2012
Backup RampD liquid argon instrumentation
- Pagina 1
- Pagina 2
- Pagina 3
- Pagina 4
- Pagina 5
- Pagina 6
- Pagina 7
- Pagina 8
- Pagina 9
- Pagina 10
- Pagina 11
- Pagina 12
- Pagina 13
- Pagina 14
- Pagina 15
- Pagina 16
- Pagina 17
- Pagina 18
- Pagina 19
- Pagina 20
- Pagina 21
- Pagina 22
- Pagina 23
- Pagina 24
- Pagina 25
- Pagina 26
- Pagina 27
- Pagina 28
-