Nuclear temperature measurements with the double Isotope ratio technique: Influence of the experimental conditions

The dependence of the nuclear temperatures of highly excited systems, extra cted by means of the double ratios of the emitted isotopes, on the experime ntal conditions is investigated. Experimental data obtained in the Xe+Cu 30 MeV/nucleon reaction are used to study the sensitivity of the method and t he effects of the energy thresholds on the obtained temperature values. We find that the temperatures extracted using the He/Li ratios can be strongly influenced by the experimental energy thresholds which are different for d ifferent elements. These distortions depend on the velocity of the emitting system and on the detection angle and therefore particular care is needed in the choice of the detectors in those experiments in which velocities are low and angles are large. The use of four isotopes of the same element mak e negligible such effects.