Freeze-out density of the 35 MeV/u 40Ar+197Au reaction

Light charged particles emitted from the reactions of 35 MeV/u 40Ar + 197Au have been measured. The slope nuclear temperature parameters and the isotope nuclear temperature parameters are extracted from the slope of energy spectra and double isotope yield ratios respectively, and on average, the slope temperatures are slightly larger than the isotope temperatures. The entropy values are extracted also with several methods by using the d/p ratios, d-like/p-like ratios, reduced yields of isotope d and the reduced multiplicities of charged particles Mred, respectively. The entropy values from the reduced yield of isotope d and the reduced multiplicity of charged particles Mred are nearly the same, and these two methods can be used in low beam energy heavy ion reactions. The charged particles emitted in rear angles are mainly from an equilibrium state source with temperature about (4.7 +- 1.2) MeV and entropy S/A = 2.5 +- 0.5, from which the Freeze-out density can be deduced. It is nearly but less than 0.1 ρ0