g-factor measurement at RISING The case of 127

g-factor measurement at RISING: The case of 127 Sn Liliya Atanasova University of Sofia

MOTIVATION g-factors reveal information about the nuclear single particle structure: wave function, spin, magnetic dipole operator, … unique probe to study changes in nuclear shell structure far from stability spin-alignment - in relativistic fission 1. Z>30 - for projectile fragmentation beams with 2. never experimentally proven ! 3. neutron rich nuclei become accessible for moments studies

METHODOLOGY Time Differential Perturbed Angular Distribution Measure Larmor precesion and decay I(t) B J Fragment beam L = -g NB/h det Field UP 1 Field DOWN det 2 2 A 2 B 2 2 L t=0 time relative phases depend on g-factor time

EXPERIMENTAL SET-UP Spin-aligned secondary beam selected (S 2 slits + position selection in SC 21) magnet + 8 RISING detectors (top view) SC 41 gives t=0 signal for -decay time measurement Pb-wall + collimator with 7. 5 cm to avoid beam scattering SC 42 validates the event Implantation: plexi degrader + 2 mm Cu (annealed) SC 43 is a veto (reject non-stopped particle events) SC 41 SC 42

g-RISING setup MW 1 BEAM music MW 2 Al degrader slits SC 41 start Pb-wall SC 43 veto 4 clusters with BGO anticompton shields and short collimators 4 clusters with the former RISING shields Electronics: VXI and DGF Stopper: 15 mm plexiglas + 2 mm Cu

Spin-alignment and g-factors of isomers in 127, 128 Sn from fragmentation of a 136 Xe beam. Dec. 2005 Beam: – 136 Xe at 600 Me. V/u Target: 9 Be Thickness: 1023 mg/cm 2 Implantation in thick stopper: 15 mm plexiglas + 2 mm Cu (cubic lattice structure, without electric field gradients) 136 Xe fragmentation at 600 Mev/u Sn

FIRST RESULTS Isomers produced in the experiment Z 128 A/Q

FIRST RESULTS 127 Sn Pinston et al. PRC 61 (2000) 4. 5(3) s 127 Sn 128 Sn

FIRST RESULTS 321 Counts Field down 28571 30427 32056 34379 1243 128 Sn(8+ Field up 1095 128 Sn Statistics 127 Sn 715 127 Sn 5720 6309 128 7 -) 127 Sn Field up Field down 321 From S. Lakshmi Statistics 128 Sn 7721 7965

Analysis is in progress

THE g-RISING COLLABORATION 1. K. U. Leuven, Belgium: N. Vermeulen, G. Neyens, S. Mallion, M. De Rydt, K. Turzó 2. University of Sofia, Bulgaria: A. Blazhev, R. Lozeva (now Leuven), P. Detistov, L. Atanasova 3. ILL Grenoble, France: G. Simpson 4. CEA, Bruyères le Chatel, France: J. M. Daugas, O. Perru 5. ISKP Bonn, Germany: H. Hübel, S Chmel 6. GSI-Darmstadt, Germany: F. Becker, P. Bednarczyk, L. Caceres, P. Doornenbal, J. Gerl, H. Grawe, M. Górska, I. Kojuharov, N. Kurz, W. Prokopowicz, T. Saitoh, H. Schaffner, H. J. Wollersheim 7. IKP Koeln, Germany: J. Jolie, G. Illie 8. IKHP Rossendorf, Germany: R. Schwengner 9. ATOMKI, Debrecen, Hungary: A. Krasznahorkay 10. The Weizmann Institute, Israel: S. Chamoli, M. Hass, B. S. Nara Singh, Laksmi 11. University of Camerino, Italy: D. Balabanski, G. Lo Bianco, K. Galdnishki, A. Saltarelli, C. Petrache 12. University of Milano, Italy: G. Benzoni, N. Blasi, A. Bracco, F. Camera, B. Million, S. Leoni, O. Wieland 13. IFJ-PAN Krakow, Poland: J. Grébosz, M. Kmiecik, A. Maj, K. Mazurek, W. Méczyński, S. Myalsky, J. Styczen, M. Zieblinski 14. Jaggielonian University, Krakow, Poland: R. Kulessa; 15. Warsaw University, Poland: M. Pfűtzner, A. Korgul 16. NIPNE, Bucharest, Romania: M. Ionescu-Bujor 17. Universidad Autonoma de Madrid, Spain: A. Jungclaus, 18. Univerity of Lund, Sweden: C. Fahlander, R. Hoishen, D. Rudolf 19. ISOLDE-CERN, Switzerland: G. Georgiev 20. University of Surrey, UK: Zs. Podolyàk, P. Regan, J. Walker, PD Paddy, PD Zsolt