First Results with the RISING active stopper

REGAN, P. H., ALKHOMASHI, N., AL-DAHAN, N., PODOLYÁK, Z., PIETRI, S. B., STEER, S. J., GARNSWORTHY, A. B., Suckling, E., STEVENSON, P. D., FARRELLY, G., CULLEN, I. J., GELLETLY, W., WALKER, P. M., BENLLIURE, J., MORALES, A. I., CASAJEROS, E., ESTEVEZ, M. E., GERL, J., GÓRSKA, M., WOLLERSHEIM, H. J., BOUTACHKOV, P., TASHENOV, S., KOJOUHAROV, I., SCHAFFNER, H., KURZ, N., KUMAR, R., RUBIO, B., ALGORA, A., MOLINA, F., GREBOSZ, J., BENZONI, G., MÜCHER, D., BRUCE, A. M., BACELAR, A. M. D., LALKOVSKI, S., FUJITA, Y., TAMII, A., HOISCHEN, R., LIU, Z., WOODS, P. J., MIHAI, C. and VALIENTE-DOBÓN, J. J. (2008) First Results with the RISING active stopper. International Journal of Modern Physics E, 17 (supp01). pp. 8-20. ISSN 0218-3013 doi: 10.1142/S0218301308011719

Abstract/Summary

This paper outlines some of the physics opportunities available with the GSI RISING active stopper and presents preliminary results from an experiment aimed at performing beta-delayed gamma-ray spectroscopic studies in heavy-neutron-rich nuclei produced following the projectile fragmentation of a 1 GeV per nucleon 208Pb primary beam. The energy response of the silicon active stopping detector for both heavy secondary fragments and beta-particles is demonstrated and preliminary results on the decays of neutron-rich Tantalum (Ta) to Tungsten (W) isotopes are presented as examples of the potential of this technique to allow new structural studies in hitherto experimentally unreachable heavy, neutron-rich nuclei. The resulting spectral information inferred from excited states in the tungsten daughter nuclei are compared with results from axially symmetric Hartree–Fock calculations of the nuclear shape and suggest a change in ground state structure for the N = 116 isotone 190W compared to the lighter isotopes of this element.