35MeV/u^(40)Ar+^(197)Au反应中热核的碎裂密度

Freeze-Out Density of the 35MeV/u^(40)Ar+^(197)Au Reaction

许多提取核反应过程中熵产生的方法只适用于高能核反应过程 ,而约化d的产额方法可以用于较低能量的重离子核反应中 .对于 3 5MeV/u40 Ar+ 197Au的核反应过程 ,利用这种方法所得的熵和约化带电粒子多重性提取的熵结果一致 .对于后角热核发射体系 ,实验提取的核温度为 ( 4.7± 1 .2 )MeV ,熵为S/A =2 .5± 0 .5,根据实验提取的熵和核温度可以确定其碎裂密度小于 0 .1

Light charged particles emitted from the reactions of 35MeV/u 40 Ar+ 197 Au 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 M r?e?d , respectively. The entropy values from the reduced yield of isotope d and the reduced multiplicity of charged particles M r?e?d 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 ρ 0.