“Precision mass and g-factor measurements for fundamental ...
Transcript of “Precision mass and g-factor measurements for fundamental ...
ACFC 2011, 487. WE-Heraeus-Seminar
“Precision mass and g-factor measurements for
fundamental studies”
Klaus BlaumJuly
19, 2011
Outline
Introduction and motivation
Principle of Penning traps
Precision mass and g-factor measurements
Setup and measurement procedure
Storage and cooling techniques
particles at nearly rest in space relativistic particles
∗
ion cooling ∗
long storage times∗
single-ion sensitivity ∗
high accuracy
Storage ring
TSR/ESR
0 2.5 5 m
Penning trap
0 0.5 1 cm
z0
r0
Single ion sensitivitySchottky
detection
in astorage
ring
SchottkyPick-ups
Stored ion beam
f ~ 2 MHz0
FFT
Narrow
band FT-ICR in aPenning
trap
5 cm 3 cm
Part I
High-precisionmass measurements
Why measuring atomic masses?
δm/m
General physics & chemistry ≤
10‐5
Nuclear structure physics‐
separation of isobars
≤
10‐6
Astrophysics
‐
separation of isomers
≤
10‐7
Weak interaction studies ≤
10‐8
Metrology ‐
fundamental constants
Neutrino physics≤
10‐9
CPT tests ≤
10‐10
QED in highly‐charged ions‐
separation of atomic states
≤
10‐11
N ·
– binding energy
+ Z · + Z ·
Sources:Accelerator or reactor basedradioactive beam facilities
and electron beam ion traps.CERN IMP/GSI MPIK TRIGA
KATRIN-TRAP
TRIGA-TRAP
THe-TRAP
PENTA-TRAP
Experimentalsetups
CSRe/ESR
ISOLTRAP
SHIPTRAP
Atomic and nuclear binding energies reflect all forces acting in the atom/nucleus.
Principle of Penning trap mass spectrometry
Cyclotron frequency:
Bmqfc ⋅⋅=
π21
B
q/m
PENNING trapStrong homogen. magnetic fieldWeak electric 3Dquadrupole field
B
Typical freq.q = e m = 100 uB = 6 T⇒
f-
≈ 1kHzf+
≈ 1MHz
ν-
ν+
νz
TOF cyclotron resonance detection
MCPDetector
(1) Excitation of theion motion
(3) TOF measurement
(2) Energy conversion
e
e
mmmm
ff
--
=refc
refc,Determine atomic mass from frequency ratio
with a well-known “reference mass”.
Bmq
πf 21
=c
Centroid:
0 1 2 3 4 5 6 7 8 9240
270
300
330
360
390
63Ga T1/2 = 32.4 s
Mea
n tim
e of
flig
ht /
μs
Excitation frequency νRF - 1445125 / Hzfrf
e
e
mmmm
ff
--
=refc
refc,Determine atomic mass from frequency ratio
with a well-known “reference mass”.
Bmq
πf 21
=c
Centroid:
0 1 2 3 4 5 6 7 8 9240
270
300
330
360
390
63Ga T1/2 = 32.4 s
Mea
n tim
e of
flig
ht /
μs
Excitation frequency νRF - 1445125 / Hzfrf
Bmq
πf 21
=c
Centroid:
0 1 2 3 4 5 6 7 8 9240
270
300
330
360
390
63Ga T1/2 = 32.4 s
Mea
n tim
e of
flig
ht /
μs
Excitation frequency νRF - 1445125 / Hzfrf
TRIGA-SPEC: TRIGA-LASER + TRIGA-TRAP
TRIGA MainzG. Hampel
K. EberhardtN. Trautmann
steady 100 kW, pulsed 250 MW, neutron flux 1.8x1011 / cm2s TRIGA-TRAP
TRIGA-LASERW. Nörtershäuser
ECR ion source
Mass separator
RFQ
Nucl. Instrum. Meth. A 594, 162 (2008)
project start @ TRIGA: 01/08start data taking: 05/09
Making gold in nature
D. Rodríguez et al., Phys. Rev. Lett. 93, 161104 (2004) X.L. Tu et al., Phys. Rev. Lett. 106, 112501 (2011)S. Baruah et al., Phys. Rev. Lett. 101, 262501 (2008) E. Haettner et al., Phys. Rev. Lett. 106, 122501 (2011)
Conditions
for
an A=80 abundance
peak
situation
2007with
new
80Zn masswith
new
81Zn mass
r-process nucleosynthesisMost nuclear data experimentally unknownTheoretical predictions neededAstrophysical site uncertainObservational data to be matched
Where is the predicted“island of stability“?
Direct mass measurements on No and LrM. Block et al., Nature 463, 785 (2010)M. Dworschak et al., PRC 81, 064312 (2010)
-15 -10 -5 0 5 1075
80
85
90
95
Mea
n To
F / μ
s
Exc. Frequency + 843324.5 / Hz
255Lr2+
256Lr radionuclide with lowest yield ever measured in a Penning trap (2 ions/minute)
Neutrino-less double EC (0ν2EC)
2ν2EC (T1/2 >1024y) 0ν2EC (T1/2 >1030y)
Is the neutrino a Majorana or Dirac particle?
0ν2EC might
be
resonantly
enhanced
(T1/2 ~1025y)
Contribution
of Penning
traps:Search
for
nuclides
with
Δ=(Qεε
−B2h -Eγ
) < 1 keVby
measurements
of
Qεε
–valuesat ~100 eV
accuracy
level
Resonance enhancement factors
152Gd: Phys. Rev. Lett. 106, 052504 (2011)
2EC - transition Δ (old), keV Δ (new), keV T1/2 • m2, yr
152Gd → 152Sm -0.2(3.5) 0.9(0.2) 1026
164Er → 164Dy 5.2(3.9) 6.81(0.12) 1030
180W → 180Hf 13.7(4.5) 12.4(0.2) 1027
THe-TRAP for KATRIN A high-precision Q(3T-3He)-value measurement
Qlit =18 589.8 (1.2) eVν++→ −eHeH 32
31
We
aim
for: δQ(3T 3He) = 20 meVδm/m = 7·10-12
ΔT < 0.05 K/d at 24°CΔB/B < 10 ppt
/ h Δx ≤
0.1 μm
First 12C4+/16O6+
mass
ratio
measurement
at δm/mstat = 4·10-11
performed.
Part II
High-precisiong-factor measurements
10 c
m
Single ion signals
B
Ctrap CpRp Lres
amplifier
detection circuit
Penning trap
Superconducting helicalresonator
Ultra-low noise cryogenic amplifier
One measurement cycle
i.Detection
of spin-orientation
in analysis
trap
ii.Transport to precision
trapiii.Measurement
of eigenfrequencies
and simultaneous
irradiation
with
microwaves
iv.Transport to analysis
trapv.Detection
of spin
orientation
in analysis
trapSpin flip in theprecision trap?
High-precision g-factor measurement
COMSOL simulation
Lωh
g-factor resonance of a single 28Si13+ ion
ion
e
mm
eqg Γ= 2
gs = 2 + ae + ab + b + c
Dirac
QEDfree electron
BS-QED
Relativistic
Nuclearcorrection
our measurement
gexp
= 1.995 348 958 7 (5)(3)(8)gtheo
= 1.995 348 958 0 (17)Error is dominated by uncertainty
of the electron mass.
Most stringent test of BS-QED in strong fields.
Coauthors from theory: Harman, Keitel, Zatorski S. Sturm et al., Phys. Rev. Lett. 107, 023002 (2011)
g-factor resonance of a single protonCompare g-factors of p and p:
Test of matter-antimatter symmetry.Highly challenging experiment since
one million times harder compared to e-.
1E-21 1E-18 1E-15 1E-12 1E-9 1E-6 1E-3
planned
e+ e-
(g-2)
p p
μ+ μ−
e+ e-
K0 K0
relative precision
H H
g-factor
mass
g-factor
mass difference
HFS-spectroscopy (planned)
charge/mass
p p
achieved
g-factor
49.8 49.9 50.0 50.1 50.2 50.3 50.4 50.5
-10
0
10
20
30
40
50
60
spin
flip
pro
babi
lity
(%)
drive frequency (MHz)
20 kHz
We aim for δg/g = 10-9.
Larmor resonance based onfirst spin flip ever observedwith a nuclear magnetic moment.
PDG:
S. Ulmer et al., Phys. Rev. Lett. 106, 253001 (2011)
Summary
-
Accurate masses have been obtained for reliable nucleosynthesis
calculations.
-
First direct mass measurements above uranium bridge the gap to the island of stability
-
Discovery of a suitable candidate for 0ν2EC search
-
Most stringent test of bound-state QED and first direct g-factor measurement on a free proton
-
Development of novel and unique storage devices
-
… and many more!
Breathtaking results in high-precision experiments with stored and cooled ions have been achieved!
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Thanks
Email: [email protected]
WWW: www.mpi-hd.mpg.de/blaum/
Thanks a lot for the invitation and your attention!