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:

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)


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)


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


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

2

V2V

=MG

Kft

K – Product of fund. constants

GV – Vector coupling constant

MV - Nuclear matrix element


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


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


62GaJYFLTRAP

LEBIT38Ca

CPT46V


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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