Tez özetleri Astronomi ve Uzay Bilimleri Anabilim Dalı

Parıty-Projected Level Densıty Calculatıons ın the Quantum

Monte Carlo Approach

One of the problems on the issue of the level density which involves in nuclear physics and astrophysics applications is distributions based on parity which is one of the primary features of level density. This topic is closely related to statistical calculations of nuclear reactions, the processes violating parity and neutron capture reactions. 
In recent years, there has been a significant development both theoretically and experimentally in level density studies which have been a basic research topic since the early times of nuclear physics. Until recently, only level density which is expressed with phenomenological models can be calculated microscopically by means of shell model Monte Carlo methods (SMMC) developed for nuclear physics for some time. However, it is clear that there are still a very small number of theoretical and experimental studies on the distribution of the level density parity. Although existing studies gave important clues about on the factors that affect the distribution of the level density parity, there were remarkable differences for some of the kernels between the experimental and theoretical findings. It is widely accepted that there is an assumption in which positive and negative parity levels in a certain energy value are equal to each other.
In this dissertation, calculate observable ones for nickel isotopes which has significant place at thermal reactions of stars in finite temperature is calculated and nuclear level density as being total and also as depending on parity is obtained by applying Quantum Monte Carlo Approach which is mentioned above and is a very successful method. Results are compared with equal distributed parity hypothesis and the accuracy of the approach is checked at various excitation energies. Moreover, the results obtained in this study are compared with existing experimental data independently and experimental level density data depending on parity which is found at J=2 channels are compared with results which are obtained by SMMC methods for ⁵⁸Ni.