Mass Measurements on Superallowed β - Emitters Using Ramsey’s Excitation Method at ISOLTRAP

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:

Bmqfc

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 cap Typical frequenciesq = e, m = 100 u,B = 6 T f- ≈ 1 kHz

f+ ≈ 1 MHzBrown & Gabrielse, Rev. Mod. Phys. 58, 233 (1986)


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

Mea

n 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

Mea

n 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 sourceion 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)


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

ff

--=

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


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


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

2V

2V

=MGK

ftK – Product of fund. constantsGV – Vector coupling constantMV - Nuclear matrix element


QQ – Decay energy – Decay energy mass mass mmTT1/21/2 – Half-life– Half-lifebb – Branching ratio– Branching ratioPPECEC – Electron capture fraction– Electron capture fractionδδRR –– Radiative correction Radiative correctionδδCC –– 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


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)]

34ArLimit from QEC(38Ca)

62GaJYFLTRAP

LEBIT38Ca

CPT46V

22Mg

74Rb

[I.S. Towner & J .C. Hardy, Phys. Rev. C 71, 055501 (2005)]

34ArLimit 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)


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

Mass Measurements on Superallowed β - Emitters Using Ramsey’s Excitation Method at ISOLTRAP

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