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

1. Mass Measurements on Superallowed β-Emitters Using Ramsey’s Excitation Method at ISOLTRAP Outline Sebastian George Tokyo 2007 High-Precision Mass Spectrometry Ramsey Method Weak Interaction Studies

2. Principle of Penning Trap Mass Spectrometry B PENNING trap • Strong homogeneous magnetic field • Weak electric 3D quadrupole field Cyclotron frequency: q/m end cap Typical frequencies q = e, m = 100 u, B = 6 T f- ≈ 1 kHz f+≈ 1 MHz ring electrode Brown & Gabrielse, Rev. Mod. Phys. 58, 233 (1986)

3. 10 cm Triple-Trap Mass Spectrometer ISOLTRAP precision Penning trap determination of cyclotron frequency (R = 107) 1,2 m B = 5.9 T preparation Penning trap removal of contaminant ions (R = 105) stable alkali ion reference source B = 4.7 T (dm/m)res= 10-8 cluster ion source G. Bollen et al., NIM A 368, 675 (1996) K. Blaum et al., EPJ A 15, 245 (2002) A. Kellerbauer et al., EPJ D 22, 53 (2003) ion beam cooler and buncher

4. 390 360 330 300 270 240 0 1 2 3 4 5 6 7 8 9 Time-of-Flight Ion Cyclotron Resonance Detection (3) TOF measurement s m (2) Energy conversion Mean time of flight / Centroid: 63 Ga T = 32.4 s 1/2 frf Excitation frequency - 1445125 / Hz (1) Excitation of the ion motion Determine atomic mass from frequency ratio with a well-known “reference mass”.

5. 38Ca (T1/2 = 440 ms) A precision gain of more than a factor of 3 is obtained. S. George et al., Phys. Rev. Lett. 98, 162501(2007) The Ramsey Excitation Method S. George et al,Int. J. Mass Spectrom., in press(2007), doi:10.1016/j.ijms.2007.04.003

6. First Online Application • 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 K – Product of fund. constants GV – Vector coupling constant MV - Nuclear matrix element George S. et al,Phys. Rev. Lett. 98 (2007) 162501.

7. m Weak Interaction symmetry tests, CVC hypothesis dm/m < 3·10-8 Experimental Access to FT-Value Q – Decay energy  mass m T1/2 – Half-life b – Branching ratio PEC – Electron capture fraction δR– Radiative correction δC– Isospin symmetry breaking correction Unitarity of the CKM matrix • Mean Ft value of all decay pairs contributes to Vud via GV • Can check unitarity via sum of squares of elements of the first row

8. ● CVC test An accuracy of the Q-value by some few 100 eV is reached by mass measurements. In addition required: Half-lifeBranching ratio ● ● ISOLTRAP: Mg-22, Al-26, Ar-34, Ca-38, Rb-74 F. 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. 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) LEBIT: Ca-38G. Bollen et al., Phys. Rev. Lett. 96 (2006) 152501 Further measurements at the Q3D magnetic spectrograph (T. Faestermann)

9. THE END Thanks 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: GSI, BMBF, CERN, ISOLDE, HGF EU networks EUROTRAPS, EXOTRAPS, and NIPNET