부산대학교 도서관

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.nima.2004.12.028 Byline: W. Reviol, D.G. Sarantites, R.J. Charity, C.J. Chiara, J. Elson, M. Montero, O.L. Pechenaya, S.K. Ryu, L.G. Sobotka Abstract: A high-efficiency evaporation-residue counter (named HERCULES) has been designed and constructed. It consists of 64 thin fast-plastic scintillators arranged in four rings covering an angular range of 3.1-19.1.sup.a at 30.9cm from the target. The device design has been optimized for use with GAMMASPHERE. Evaporation residues are well separated from elastic scattering, fission events, and other undesirable reaction debris by time-of-flight and pulse-height analysis. Each detector element can operate at rates up to 0.5MHz with signal recovery in about 10ns. The geometry, construction, light-output characteristics, stability of the measured quantities, associated electronics, and in-beam performance of the device are described. For energy-degraded fission fragments with kinetic energies of less than 45MeV, it is found that (1) the Z dependence of the pulse height disappears and (2) the light output per unit energy increases with decreasing energy. For evaporation residues from two reactions, in which the evaporation channels dominate and in which the residue cross-section is about 100 times smaller than the fission cross-section, angular distributions and sample [gamma]-ray spectra are shown. Author Affiliation: Department of Chemistry, Washington University, 1 Brookings Drive, St. Louis, MO 63130, USA Article History: Received 21 September 2004; Revised 23 November 2004; Accepted 1 December 2004