1. Mass measurements using low energy ion beams -1- C. Thibault 31 mars 2004 Motivations to measure masses Present status Experimental methods for direct mass measurements Current developments

2. Nuclear Structure Astrophysics Weak interaction Motivations -2- C. Thibault 31 mars 2004

3. Nuclear structure -3- C. Thibault 31 mars 2004 Neutron number Shell closure deformations Accuracy : 100 keV  10 -6 at A=100

4. r-process Mass models -4- C. Thibault 31 mars 2004

5. High accuracy Nuclear Structure shell quenchings10 -6 Pairing, halos10 -7 Astrophysics new shells far from stability 10 -5 Weak interaction superallowed transitions  CVC tests10 -8 High sensitivity rare nuclei production (much) less than 1000/s short-lived nuclei half-life (much) less than 100 ms Requirements -5- C. Thibault 31 mars 2004

6. Merit of experimental methods -6- C. Thibault 31 mars 2004 Lunney et al. 2003

7. Mass measurements accuracy -7- C. Thibault 31 mars 2004 Nucleus 2003

8. Recent mass measurements -8- C. Thibault 31 mars 2004 Lunney et al. RMP 75 (2003) 1021

9. α, β -, β + Decay- energies -9- C. Thibault 31 mars 2004 Masses measured since 1994 and used in AME 2003: Q α 4 – 30 keV ~ 300 ~ 100 isomers Q β- 10 – 100 keV ~ 80 Q β+ 50 – 100 keV ~ 50 Q α : α or α-γ spectroscopy Q β : β-γ spectroscopy or Total Absorption Spectrometry

10. Low energy direct measurements -10- C. Thibault 31 mars 2004 Mass  Cyclotron frequency B calibration  2-mass comparison At constant B :

11. Mistral principle -11- C. Thibault 31 mars 2004 Mass measurement at ISOLDE with a Transmission and RAdiofrequency spectrometer on-Line Cyclotron frequency measuremen t MIS RAL

12. 2-mass comparison Mistral layout -12- C. Thibault 31 mars 2004 MIS RAL

13. Penning trap scheme -13- C. Thibault 31 mars 2004

14. Trajectory in a Penning trap -14- C. Thibault 31 mars 2004 A = 100, q = 1, B = 6T Axial pulsation z  44 kHz Reduced cyclotron rotation +  1 MHz Magnetron rotation (slow) –  1 kHz B ω + + ω – = ω c

15. Isoltrap layout -15- C. Thibault 31 mars 2004 ISOLDE 60 keV ion beam MCP Time-of-flight Detector RFQ-Cooler-Buncher Beam preparation Preparation Penning Trap Cooling of ion beam Cleaning of isobars Precision Penning Trap mass measurement: Cyclotron frequency determination

16. Penning traps at work -16- C. Thibault 31 mars 2004 beam prepa measures main topics Isoltrap Isolde 1+ ~200 N~Z, n-rich, isotopic series CERN Smiletrap Crysis ++++ ~10 Q ββ, ν mass Stockholm Jyfltrap Igisol 1+ [~10] N~Z, (refractory elements) Jyväskylä 2 CPT gas cell 1+ ~10 n-rich (Cf fission), N~Z Argonne

17. Penning traps in development -17- C. Thibault 31 mars 2004 beam prepa status main topics Shiptrap gas cell 1+ injection OK Transactinides Darmstadt Superheavies Lebit 9T trap gas cell 1+ injection tests N~Z, n-rich MSU trap construction (very short half-lives) Mafftrap [Isol] construction n-rich (fission) München gas cell 1+ Transuranides, Superheavies TITAN ISAC construction (very short half-lives) Vancouver Ebit +++ 2005?

18. -18- C. Thibault 31 mars 2004

19. Mass connections -19- C. Thibault 31 mars 2004 A. H. Wapstra et al. Nucl. Phys. A729 (2003) 129

20. TITAN layout -20- C. Thibault 31 mars 2004 ISAC DC ion beam RFQ Cooler + buncher EBIT Charge breeder m/q Selection stage Precision Penning trap EBIT

21. Mass predictions -21- C. Thibault 31 mars 2004 Lunney et al. RMP 75 (2003) 1021

22. Mass connections -22- C. Thibault 31 mars 2004 G. Audi et al.

23. Mistral examples -23- C. Thibault 31 mars 2004 Cyclotron frequency Phase selection after first modulation radiofrequency 480324.92  0.11 kHz 2.10 -7 70000 MIS RAL

24. Mistral measurements -24- C. Thibault 31 mars 2004 N = 37 87848586888975747677797880818283 8683 84 85747578777981 82 Sr Rb 88787 76 80 T 1/2  1 s stable MISTRAL T 1/2  100 ms 11 Li 25-26 Ne 26-30 Na 29-33 Mg 74 Rb Ne 232425 21 24 26 27 N = 20 Na 2829 Al 28 31 34 29 30 22 3330 31 23 32 312425262829 Mg 30322733 27 2627282930 25 32 31 He 6 7 3 68 N = 8 Li 4 7 10 Be 1214 9 8911

25. ISOLTRAP components