Testing the Level Density of A Similar-to-100 Hot Nuclei From Evaporative Charged-particle Spectra

Alpha particles and protons emitted in the S-32 + Ge-74 reaction at E = 160, 210, 259, 335 and 435 MeV were measured in coincidence with evaporation residues. The average inverse level-density parameter [K] for hot evaporation residues with A approximately 100 was obtained by comparing the slope of the charged-particle spectra with the predictions from a full statistical model calculation. Spectral shapes are well reproduced by calculations using the standard values [K] = 7.5 MeV, except for alpha particles at the highest bombarding energy, which corresponds to an excitation energy epsilon = 2.2 MeV/nucleon. The present results are compared with other experimental investigations in the A approximately 100 and A approximately 160 regions and with predictions from theoretical models. Difficulties in extracting the nuclear temperature from the slope of the particle spectra for A approximately 100 are discussed.