The multifragment emission of completely characterized'' events in the {sup 40}Ca+{sup 40}Ca system at 35 MeV/nucleon has been compared to the predictions of several models. The observed ...multifragment emission is not in agreement with models based on conventional statistical binary decay, but is in agreement with both a simultaneous multifragmentation model and a sequential emission model in which expansion is treated.
For hot nuclei with ital Acongruent120, 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 sup 4He and sup 5Li detection.
Excitation energy depositions in the reactions of 40ital A MeV sup 40Ar with sup 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)times10sup minus20 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.
The multiplicities of ital p and alpha particles detected in coincidence with fragments emitted in fully relaxed collisions in the reactions of 18.5ital A MeV sup 136Xe+sup 48Ti have been measured ...for different exit channel mass asymmetries. A kinematic source analysis of the spectra and angular distributions of the light particles has been used to separate the total multiplicities into prescission and postscission contributions. From these results, the excitation energies at scission are determined using an empirical technique based upon previous measurements of light charged particle multiplicities observed in coincidence with evaporation residues. These excitation energies are found to decrease from similar to400 MeV to 110 MeV as the fragment mass asymmetry, ital Asub ital H/ital Asub ital L, varies from 4.8 to 1.0. A corresponding increase of the mean lifetime of the scissioning nucleus from similar to5times10sup minus22 s to similar to1times10sup minus20 s is derived using calculated statistical model decay widths. The extent to which this variation of lifetime with mass asymmetry may be attributed to completely damped deep inelastic collisions or to dynamic delays in the decay of a compound nucleus is discussed as is the need for inclusion of dynamics in the deexcitation calculations for hot nuclei. Observed three fragment events are also discussed.
![Intercalibration of [sup 4]...](http://api.summon.serialssolutions.com/2.0.0/image/issn/XR4PS5YY4K/0556-2813/small "Intercalibration of [sup 4]He and [sup 5]Li nuclear thermometers for hot nuclei")