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Silicon Drift Detectors for the kaonic atom X-ray

measurements in the SIDDHARTA experiment

T. Ishiwatari Stefan Meyer Institut, Vienna, Austria

SIDDHARTA CollaborationSilicon Drift Detector for Hadronic Atom Research by Timing Applications

LNF- INFN, Frascati, ItalyStefan Meyer Institut, Vienna, Austria

Politecnico, Milano, ItalyMPE, Garching, Germany

PNSensors, Munich, GermanyIFIN – HH, Bucharest, Romania

Univ. Victoria, CanadaRIKEN, Japan The 11th VCI 2007 Feb 19-24,2007

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Silicon Drift Detectors for the kaonic atom X-ray measurements in the SIDDHARTA experiment

1. Kaonic atom X-rays

2. Kaonic hydrogen with CCDs

(DEAR, LNF)

3. Silicon Drift Detectors

4. Kaonic helium with SDDs

(E570,KEK)

5. Kaonic hydrogen & deuterium with SDDs

by Monte Carlo

(SIDDHARTA, LNF)

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)(

22

2311

FormulaDeser

ai ss

)(

22

2311

FormulaDeser

ai ss

Shift () and width () of K-p and K-d gives isospin dependent KN scattering lengths(a0 and a1)

These scattering lengths provide Low-energy SU(3) QCD:SU(3) chiral symmetry, KN -term, nature of (1405), S0 ( 3115 ) S + (3140)

Difficulty1. High-background

in kaon beams

2.Small X-ray yields

(a few% K-p, below 1% K-d)

3.Precise determination of

X-ray energy and width

X-ray detector with 1. high background rejection,

2. large-area,

3. good resolution in energy and time

Kaonic atom X-rays and KN scattering lengths

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Katom Old exp.

1H Attractive shift

2D No data

3He No data

4He Large shift

New exp.

Repulsive shift

No data

No data

Small shift

repulsive attractive

-500 5000

wid

th

1s

[eV

]

0

200

400

600

800

1000

shift 1s [eV]

Dav

ies

Izyc

ki e

t al,

1980

Bird

198

3

Results of kaonic hydrogen

Accuracy for K-p,First for K-d(as well as 4He,3He)are badly needed!

Experimental results of kaonic atoms

KpX

DEAR

Iwas

aki e

t al,

1997

Phys. Rev. Lett. 94, 212302 (2005)

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DEAR

DAFNE e+e- collider optimized to produce -meson at rest (1.020 GeV)

KKee KKee

K- beam at DAFNE1. Monochromatic2. Low-energy3. No hadronic background

K- beam at DAFNE1. Monochromatic2. Low-energy3. No hadronic background

/day103~

/day2~

,3000~

6

1

K

pbdtL

nbKK

DEAR experiment at DAFNE

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DEAR experimental setup

TMP

CCD Electronics

Vacuum Chamber

APD Cryo-Cooler

CryoTigerCCD Cooling

CCD Pre-Amplifier

CCD55-Chips

Kaon MonitorKaon Monitor

16 CCD55-30 (EEV) -1242 x 1152 pixels - pixel size 22.5 x 22.5 m- total area 7.24 cm2 per chip- depletion depth ~30 m- read-out time 1 min.- energy resolution ~150 eV @ 6keV- temperature at 165 K

16 CCD55-30 (EEV) -1242 x 1152 pixels - pixel size 22.5 x 22.5 m- total area 7.24 cm2 per chip- depletion depth ~30 m- read-out time 1 min.- energy resolution ~150 eV @ 6keV- temperature at 165 K

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X-ray events 1 and 2 pixel eventsCharged particles large pixel eventsbackground suppression by pixel analysis

CCD X-ray detector

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S/N~1:70

PRL 94, 212302 (2005)

1s = - 193 ± 37 (stat.) ± 6 (syst.) eV1s = 249 ± 111 (stat.) ± 30 (syst.) eV

1s = - 193 ± 37 (stat.) ± 6 (syst.) eV1s = 249 ± 111 (stat.) ± 30 (syst.) eV

DEAR results

K-p energy spectrum by DEAR CCDs

X-ray events

NIMA 556(2006)509

X-rays : 1,2 pixelsMIPs :~ 8 pixels,Some MIPs: ~ 1,2 pixelsbackground events on X-ray spectraTiming needed!

Part

s of

MIP

s ~1,

2 pi

xels

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SDD (Silicon Drift Detector) X-ray detector

Low capacitance

SDDSi(Li)

electrode type

anodecathode

small anode large-area, high energy resolution,Thin depletion reduce background caused by electron/gamma

Q = CV = (ε0S / d ) V

Q = CV = (ε0S / d ) V

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Si(Li) SDD

Detector Si(Li) CCD SDD

Area [mm2] 200 724 100

Thickness [mm] 5 0.03 0.30

E (FWHM)

[eV] 410 170 185

t (FWHM) [ns] 290 - 430

Comparison of X-ray detectors used for kaonic X-ray experiments

These values are obtained during the beam times.

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Kaonic Helium X-rays with SDDs (E570, KEK)

KETEK 1 cm2 SDD

E570

Energy resolution ~185 eV @ 6 keV

Effective Area 1cm2 * 8 SDDs

Thickness 0.26 mm

Temperature ~85 K

Energy calibrationIn-beam

(Ti and Ni)

Fiducial volume cut Yes

K-4He La X-rays

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1) 8 Silicon Drift Detectors “SDDs”1) 8 Silicon Drift Detectors “SDDs”

K-

X-ray

Charged particles

LHe target

3) Reconstruction of K and charged particles

3) Reconstruction of K and charged particles

Drift chamber (PDC,VDC)

BDC

E570 experimental setup

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2 4 6 8 10

Energy [keV]

1

10

10

10

10

105

4

3

2

1

Cou

nts/

30 e

V

Self trigger

Events from target cell

104 times less

Ti K

KHe 3-2

Ni Ka

KHe 4-2

KHe 5-2

Kaonic 4He Energy spectra with SDDs

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SIDDHARTA experiment (LNF, Italy)

New SDDs specially designed for SIDDHARTA

200 SDDs with 1cm2 per SDDon-chip preamp

New SDDs specially designed for SIDDHARTA

200 SDDs with 1cm2 per SDDon-chip preamp

Silicon Drift Detectors for Hadronic Atom Research

by Timing Application

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Triple coincidence: SDDX * ScintK * ScintK

Scintillator

Scintillator

Target

SD

De+

e-

S/N =1:70 (CCD)10:1 (SDD)for kaonic Hydrogen

K+

Φ K+ + K-

K-

Triple coincidence technique

X-ray

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Temperature 22 KPressure max. 5 bar

Kaon entrance Window:Kapton 150 m

Side wall:Kapton 75 µm

200 SDDs with 1cm2 per SDD

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SDDs electronics

Cryogenic target cell

Kaon entrance window

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Energy (keV)

Background suppression >103

MIPs (e+/e-) in SDD

Kaon decays

Signal rate ~ 2.2x10-3 /s130 /d (duty cycle=2/3 of d.)

Monte Carlo for SIDDHARTA

W/o coincidence

With coincidence ofK+, K-, X-ray

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Energy (keV)

Kaonic hydrogen

Kaonic deutrium

K Kβ

Kg, ...

K-p: ε1s = 193 eV, Γ1s = 249 eV, Y(Kα )=2%precision: ε1s ± 3 eV Γ1s ± 5 eV

K-d: ε1s = 325 eV, Γ1s = 630 eV, Y(Kα )=0.2%precision: ε1s ± 18 eV Γ1s ± 45 eV

Energy spectra in SIDDHARTA (Monte Carlo)

Signal rate ~ 2.2x10-3 /s130 /d (duty cycle=2/3 of d.) 30 days data taking

S/N=10:1

S/N=1:1

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Summary•Application of SDD X-ray detectors in the field

of kaonic atoms is given.•SDDs have good Energy resolution as well as good Time resolution.•Prototype of Large-area SDDs are tested with a kaon beam at

KEK successfully.•High performance on Energy resolution, Time resolution, Background rejection capability was measured.•We are now developing new type of Large-area SDDs specially designed for SIDDHARATA experiment.•SIDDHATA will obtain

the most accurate for kaonic hydrogen X-rays, and the first observation of kaonic deuterium X-rays.

•The physics runs start from 2007.

Part of the work was supported by "Transnational Access to Research Infrastructure" (TARI),HadronPhysics I3, Contract No. RII3-CT-2004-506078.

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Silicon Drift Detector

GND

UBACK

UIRUOR

high energy resolution at fast shaping times, due to the small anode capacitance

Q = CV = (S / d ) V

Q = CV = (S / d ) V

Small capacitance

SDDSi(Li)

electrode type

anodecathode

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1) 8 Silicon Drift Detectors “SDDs”1) 8 Silicon Drift Detectors “SDDs”

K-

2) Ti and Ni foils2) Ti and Ni foils

X-ray

Charged particles

LHe target

-(or K-)

3) Reconstruction of K and charged particles

3) Reconstruction of K and charged particles

Ti,Ni X-rays

Drift chamber

Scint

E570 experimental setup