High-Precision Mass Measurements for Reliable Nuclear-Astrophysics Calculations

1. NIC-IX, CERN, Geneva, June 29, 2006 High-precision mass measurements for reliable nuclear-astrophysics calculations Alexander Herlert CERN, PH-IS

2. NIC-IX, CERN, Geneva, June 29, 2006 High-precision mass measurements for reliable nuclear-astrophysics calculations Atomic masses of radionuclides The ISOLTRAP experiment Principle of mass measurement Recent experimental results

3. Nucleosynthesis and r-process Pb s-process protons r-process Sn Ni 82 50 fusion in stars neutrons courtesy: K. Blaum, H. Schatz

4. Atomic Mass Evaluation 2003 In total: 3180 nuclides Measured masses: 2228 Proton Number Z all nuclides Neutron Number N G. Audi, A.H. Wapstra, C. Thibault, Nucl. Phys. A 729

5. Atomic Mass Evaluation 2003 In total: 1158 nuclides Proton Number Z dm/m < 10-7 Neutron Number N G. Audi, A.H. Wapstra, C. Thibault, Nucl. Phys. A 729

6. Atomic Mass Evaluation 2003 In total: 181 nuclides Proton Number Z dm/m < 10-8 Neutron Number N G. Audi, A.H. Wapstra, C. Thibault, Nucl. Phys. A 729

7. Atomic Mass Evaluation 2003 In total: 24 nuclides Proton Number Z 133,134Cs 85,87Rb dm/m < 10-9 Neutron Number N G. Audi, A.H. Wapstra, C. Thibault, Nucl. Phys. A 729

8. JYFL TRAP SMILETRAP  Jyväskylä Stockholm  TITAN SHIPTRAP HITRAP LEBIT GSI  TRIUMF  Munich RIKEN TRAP CERN   MSU Argonne LBL MAFF TRAP ISOLTRAP REXTRAP ATHENA ATRAP WITCH CPT RETRAP Penning traps at accelerators  operating facilities  facilities under construction or test  planned facilities

9. Production of radioactive nuclides at ISOLDE

10. Production of radioactive nuclides at ISOLDE

11. precision trap preparation trap buncher ISOLTRAP: Experimental setup 2m

12. determination of cyclotron frequency (R = 107) 2 m removal of contaminant ions (R = 105) Bunching of the continuous beam ISOLTRAP: Experimental setup B = 5.9 T B = 4.7 T G. Bollen, et al., NIM A 368, 675 (1996) F. Herfurth, et al., NIM A 469, 264 (2001)

13. B + q/m motional modes of ion stored in a Penning trap Principle of mass determination measurement of cyclotron frequency

14. Conversion of magnetron into cyclotron motion Scan QP-excitation freq. nrf about nc Magnetron excitation Quadrupole excitationnrf radial  axial energy z MCP Detector passing B-field gradient after ejection Time-of-flight (TOF) Trap B Principle of mass determination

15. Principle of mass determination mean TOF TOF spectrum Example: 85Rb (900ms excitation duration)

16. Principle of mass determination mean TOF TOF spectrum fit of theoretical line shape to the data Example: 85Rb (900ms excitation duration)

17. Principle of mass determination cyclotron frequency of well-known nuclide cyclotron frequency of "unknown" nuclide determination of mass ratio

18. 133Cs 39K 23Na 85Rb Stable alkali ions as mass references

19. C4 C11 C12 C10 C3 C9 C2 C8 C7 C6 C18 C19 C5 C17 C4 C16 C15 C14 C22 C13 C21 C12 C20 C11 C19 C18 Carbon clusters as mass references C1 K. Blaum et al., EPJ A 15, 245 (2002)

20. Determination of the mass accuracy Combined carbon cluster cross-reference measurements dm/m / 10-8 m / u Relative mass accuracy limit: (dm/m)lim= 810-9 A. Kellerbauer et al., EPJ D 22, 53 (2003)

21. ISOLTRAP mass measurements in 2004-2005 Nuclides measured in 2004/2005 127,128,131-134Sn 126Xe, 136Xe 118,120,122-124Cd 84Kr, 86-95Kr Highlights Nuclide Half-life Uncertainty 22Mg 71-81Zn 17Ne 109 ms 530 eV 35-38K, 43-46K 3.86 s 270 eV 22Mg 21-22Na 178 ms 530 eV 35K 17Ne, 19Ne 290 ms 3.45 keV 81Zn

22. The mass of 22Mg • 10 frequency ratios measured • 16 relations included in c2 adjustment 22Mg+ M. Mukherjee et al., Phys. Rev. Lett. 93, 150801 (2004).

23. Solving the mass discrepancy of 22Mg CPT J. Clark et al. 200 eV M. Mukherjee et al., Phys. Rev. Lett. 93, 150801 (2004).

24. Ion yields at ISOLDE protons neutrons

25. Ion yields at ISOLDE protons yield (ions/mC) SC and PSB yields neutrons courtesy: M. Turrion

26. ISOLDE target for Zn run quartz transfer line UCx target RILIS protons courtesy: T. Stora et al.

27. Yields at ISOLTRAP estimate for target/ion source 0.5%

28. Preliminary result for mass excess Zn 81Zn+ Zn

29. Ion yields at ISOLDE protons yield (ions/mC) SC and PSB yields neutrons courtesy: M. Turrion

30. e+ e+ A A A A A ZX ZX ZX ZX ZX e+ A A A Z-1Y Z-1Y Z-1Y • Make more radioactive species available • Nearly simultaneous wc measurement of mother and daughter nuclei • Test candidate: 37K  37Ar A A ZX Z-1Y e+ e+ A novel idea: In-trap decay mass spectrometry Decay in the buffer-gas-filled preparation trap produced at ISOLDE 4He 4He + e+ 4He not produced at ISOLDE 4He 4He 20 cm z (mm) 4He 4He 4He 4He 4He Herlert et al., New J. Phys. 7, 44 (2005)

31. In-trap decay results 37Ar+ 37K+ mass spetrometry of daughter nuclide Elements/isotopes which are in principle not produced are accessible!

32. First application of in-trap decay mass spectrometry 61Fe+

33. Summary • mass determination with a time-of-flight cyclotron resonance • detection technique • limited by: • nuclide production rate above 100 s-1 • half-life (so far) over 65ms • systematic uncertainty limit: (dm/m)lim= 810-9 • so far mass measurements on more than 300 radionuclides • at ISOLTRAP for tests of nuclear structure, mass models, • a contributions to a CKM unitarity test, ... • new techniques and development: • in-trap decay method, new ion sources and detector, • magnetic field stabilization, new excitation schemes, ...

34. Not to forget … Thanks a lot for your attention! Thanks to my co-workers: G. Audi, S. Baruah, D. Beck, K. Blaum, G. Bollen, M. Breitenfeldt, P. Delahaye, M. Dworschak, S. George, C. Guénaut, U. Hager, F. Herfurth, A. Kellerbauer, H.-J. Kluge, D. Lunney, M. Marie-Jeanne, M. Mukherjee, S. Schwarz, R. Savreux, L. Schweikhard, C. Weber, C. Yazidjian, ..., and the ISOLTRAP and ISOLDE collaboration Thanks for the funding and support: BMBF, GSI, CERN, ISOLDE, EU networks EUROTRAPS, EXOTRAPS, and NIPNET