Search Results (2 total)

Excitation energy depositions in the reactions of 40A MeV ⁴⁰Ar with ²³²Th have been determined from measurements of neutron multiplicities in coincidence with mass identified heavy reaction products. For the most central collisions the derived excitation energies of 880 MeV are 200–300 MeV above previous estimates and in excellent agreement with momentum transfer systematics. Heavy evaporation residues are observed for these collisions indicating apparent dynamic delays in the fission channel of (1–5)×10^-20 s. While a massive-transfer simulation incorporating preequilibrium emission is in generally good agreement with the experimental results evidence is also found for strongly damped collisions.

For hot nuclei with A≃120, a comparison is made between nuclear temperatures derived from spectral slope parameters for well-characterized equilibrated systems and those derived from state population ratios. When suitable account is taken of the deexcitation cascade, the two techniques lead to similar results, confirming the utility of the state ratio method. The general relationship between the measured quantities and the initial temperature for medium to heavy mass hot nuclei is discussed and a calibration of these is presented for measurements based on ⁴He and ⁵Li detection.