HOT NUCLEI AS VIEWED THROUGH 4-PI NEUTRON MULTIPLICITY FILTERS

Several aspects of hot nuclei are examined in the present review artic le. After defining what is usually meant by hot nuclei, the new tools which have been developed in order to determine the temperature are de scribed. Using several examples, it is demonstrated that the 4pi neutr on multiplicity filters constitute a powerful and reliable means for n uclear temperature measurements. So far, hot nuclei have been essentia lly investigated through nucleus-nucleus collisions. The conditions of formation of hot nuclei in such collisions, as a function of the entr ance channel parameters (bombarding energy, mass asymmetry, impact par ameter) are studied in detail. Two specific decay channels of hot nucl ei: binary fission and emission of intermediate mass fragments, as wel l as the combined effect of temperature and spin are reviewed. It is s hown that energetic light particles can also be successfully used to g enerate hot nuclei. Such nuclei left with little initial compression a nd spin are of special interest in order to investigate the effect of heat and only heat on the properties and on the fate of nuclei. This i s not possible in nucleus-nucleus collisions. Prospects are finally gi ven, with the annihilation of energetic antiprotons in nuclei appearin g as the most promising method of reaching the limiting temperature th at a nucleus can sustain.