mass measurements on superallowed β-emitters using ramsey’s excitation method at isoltrap...
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Mass Measurements on Superallowed β-Emitters Using Ramsey’s Excitation
Method at ISOLTRAP
Sebastian GeorgeSebastian George
Tokyo 2007Tokyo 2007
OutlineOutline
Weak Interaction Weak Interaction StudiesStudies
High-Precision Mass Spectrometry High-Precision Mass Spectrometry
Ramsey MethodRamsey Method
www.physik.uni-mainz.de/quantum/mats
Principle of Penning Trap Mass SpectrometryPrinciple of Penning Trap Mass Spectrometry
Cyclotron frequency:Cyclotron frequency:
Bm
qfc
21
B
q/m
B
q/m
PENNING trapPENNING trap Strong homogeneous Strong homogeneous
magnetic fieldmagnetic field
Weak electric 3DWeak electric 3D
quadrupole fieldquadrupole field
z0
r0
ring electrode
end capTypical frequenciesq = e, m = 100 u,B = 6 T
f- ≈ 1 kHzf+ ≈ 1 MHz
Brown & Gabrielse, Rev. Mod. Phys. 58, 233 (1986)
www.physik.uni-mainz.de/quantum/mats
ISOLDEbeam (DC)
HV platform
RFQ structure
MCP 5
precisionPenningtrap
coolingPenningtrap
carbon clusterion source
2.8-keV ionbunches
laser beam
MCP 3
MCP 1
60 keV
stable alkaliion referencesource
C60 pellet
80
100
120
140
160
180
200
220 32Ar
Me
an
TO
F
(s)
RF 2842679 (Hz)-40 -30 -20 -10 0 10
Triple-Trap Mass Spectrometer ISOLTRAPTriple-Trap Mass Spectrometer ISOLTRAP
ISOLDEbeam (DC)
HV platform
RFQ structure
MCP 5
precisionPenningtrap
coolingPenningtrap
carbon clusterion source
2.8-keV ionbunches
laser beam
MCP 3
MCP 1
60 keV
stable alkaliion referencesource
C60 pellet
80
100
120
140
160
180
200
220 32Ar
Me
an
TO
F
(s)
RF 2842679 (Hz)-40 -30 -20 -10 0 10
10 cm
precision Penning trap
determination ofcyclotron frequency
(R = 107)
preparation Penning trap
removal of contaminant ions
(R = 105)
cluster ion source
ion beam cooler and buncher
stable alkali ionreference source B = 4.7 T
B = 5.9 T
1,2
m
(m/m)res 10-8
K. Blaum et al., EPJ A 15, 245 (2002) A. Kellerbauer et al., EPJ D 22, 53 (2003)
G. Bollen et al., NIM A 368, 675 (1996)
www.physik.uni-mainz.de/quantum/mats
Time-of-Flight Ion Cyclotron Resonance DetectionTime-of-Flight Ion Cyclotron Resonance Detection
MCPDetector
(1) Excitation of the ion motion
(3) TOF measurement
(2) Energy conversion
e
e
mmmm
f
f
--
=refc
refc,Determine atomic mass from frequency ratio
with a well-known “reference mass”.
Bmq
πf
21
=c
Centroid:
frf
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
/ s
Excitation frequency - 1445125 / Hz
www.physik.uni-mainz.de/quantum/mats
The Ramsey Excitation MethodThe Ramsey Excitation Method
S. George et al., Phys. Rev. Lett. 98, 162501(2007)
38Ca (T1/2 = 440 ms)
A precision gain of more than a factor of 3 is obtained.
S. George et al, Int. J. Mass Spectrom., in press (2007),doi:10.1016/j.ijms.2007.04.003
www.physik.uni-mainz.de/quantum/mats
First Online ApplicationFirst Online Application
George S. et al, Phys. Rev. Lett. 98 (2007) 162501.
• Mass measurements on superallowed β-emitters • 38Ca (T1/2=440ms) and 26Al (T1/2=6.35s)#
• Relative uncertainty at the level of 1*10-8
• not limited by the statistical uncertainty• ME(38Ca)=-22058.11 (60) keV and ME(26Ca)=-12210.19 (22) keV # The superallowed β-emitter is 26Alm
2
V2V
=MG
Kft
K – Product of fund. constants
GV – Vector coupling constant
MV - Nuclear matrix element
www.physik.uni-mainz.de/quantum/mats
QQ – Decay energy – Decay energy mass mass mmTT1/21/2 – Half-life– Half-life
bb – Branching ratio– Branching ratioPPECEC – Electron capture fraction– Electron capture fraction
δδRR –– Radiative correction Radiative correction
δδCC –– Isospin symmetry breaking correction Isospin symmetry breaking correction
Unitarity of the CKM matrixUnitarity of the CKM matrix
– Mean Mean Ft Ft value of all decay pairs contributes to value of all decay pairs contributes to VVudud via via GGVV
– Can check unitarity via sum of squares of elements of the first rowCan check unitarity via sum of squares of elements of the first row
)δ,δ,P,b,T,Q(FtFt C/ REC215=
m/m < 3·10-8
Weak Weak InteractionInteractionsymmetry tests,CVC hypothesis
d's'b'
dsb
Vud
Vcd
Vtd
Vus Vub
VcbVcs
VtbVts
= · 2A
2V2
ud =GG
V
Experimental Access to FT-ValueExperimental Access to FT-Value
www.physik.uni-mainz.de/quantum/mats
CVC testCVC test
ISOLTRAP: Mg-22, Al-26, Ar-34, Ca-38, Rb-74F. Herfurth et al., Eur. Phys. J. A 15, 17 (2002)A. Kellerbauer et al., Phys. Rev. Lett.93, 072502 (2004)M. Mukherjee et al., Phys. Rev. Lett. 93, 150801 (2004)S. George et al., Phys. Rev. Lett. 98 (2007) 162501.
An accuracy of the Q-value by some few 100 eV is reached by mass measurements.
In addition required:
Half-lifeBranching ratio
JVL-TRAP: Al-26m, Sc-42, Ga-62T. Eronen et al., Phys. Rev. Lett. 97, 232501 (2006) T. Eronen et al., Phys. Lett. B 636, 191 (2006) B. Hyland et al., Phys. Rev. Lett. 97, 102501 (2006)
CPT: Mg-22, V-46G. Savard et al., Phys. Rev. Lett. 95, 102501 (2005)J. Clark et al., Phys. Rec. C 70, 042501(R) (2004)
22Mg
74Rb
[I.S. Towner & J .C. Hardy, Phys. Rev. C 71, 055501 (2005)]
34Ar
Limit from QEC(38Ca)
62GaJYFLTRAP
LEBIT38Ca
CPT46V
22Mg
74Rb
[I.S. Towner & J .C. Hardy, Phys. Rev. C 71, 055501 (2005)]
34Ar
Limit from QEC(38Ca)
62GaJYFLTRAP
LEBIT38Ca
CPT46V
Limit from QEC(38Ca)
62GaJYFLTRAP
LEBIT38Ca
CPT46V
●●
●
LEBIT: Ca-38G. Bollen et al., Phys. Rev. Lett. 96 (2006) 152501Further measurements at the Q3D magnetic
spectrograph (T. Faestermann)
www.physik.uni-mainz.de/quantum/mats
THE ENDTHE END
Thanks a lot toThanks a lot to
K. Blaum, M. Dworschak, C. Guénaut, A. Herlert, F. Herfurth, A. Kellerbauer, J. Ketelaer, H.-J. Kluge, M. Kretzschmar, M. Kowalska, D. Lunney, S. Nagy, D. Neidherr, S.Schwarz, L. Schweikhard, C. Yazidjian, and the ISOLTRAP and MATS collaboration
Thanks for funding and support:Thanks for funding and support:
GSI, BMBF, CERN, ISOLDE, HGF EU networks EUROTRAPS, EXOTRAPS, and NIPNET
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