Isospin Effect On Relative State Population Temperature In The Reactions Ar-40+Sn-112,Sn-124 At 30mev/U

An array of 13 detector telescopes has been used for detecting small-angle particle-particle correlations in the reactions Ar-40 + (112,124) Sn at 30MeV/u. The alpha-alpha correlation functions were extracted from two-particle coincident events. A three-body trajectory code MENEKA was used to calculate the background correlation function. The detection efficiency was calculated by using the Monte-Carlo method. After subtracting the background correlation and making the detection efficiency correction, the temperatures of 4.18 +/- 0.25/0.21 MeV and 4.10 +/- 0.22/0.20MeV are obtained from relative populations of 0.21/0.20 Be-8 states for the reaction systems with different isospin, (40) Ar + (112) Sn and (40) Ar + (124) Sn, respectively. From the relationship between the state population temperature and outgoing particle energies, it is found that the emission temperature decreases with increase of the particle energies for both studied reaction systems. For the neutron deficient system (40) Ar + (112) Sn the emission temperature is 5.13 +/- 0.30/0.26MeV for the lower emitting particle energies and 3.87 +/- 0.37/0.29 MeV for the higher emitting particle energies. And for the neutron rich system (40) Ar + (124) Sn the emission temperature is 5.39 +/- 0.30/0.26MeV for the lower emitting particle energies and 3.32 +/- 0.28/0.23MeV for the higher emitting particle energies. This kind of isospin dependence is discussed.