SUMMARY
The well-known inputs for determining the reaction cross section are nuclear level density (NLD) and -ray strength functions. In this work, effects of -ray strength functions and NLD models on photoneutron reactions of 76,77,78Se isotopes are analyzed by using the latest version of TALYS computer code. For -ray strength functions, macroscopic and microscopic options which are available in the TALYS, are used in the calculations. Kopecky-Uhl and Brink Axel -ray strength function models as macroscopic options, Hartree-Fock BCS tables, Hartree-Fock Bogolyubov tables and Goriely’s hybrid model as microscopic options are preferred. The statistical analysis is carried out to determine the -ray strength function that reproduces the experimental data quite well. And then, calculations of photoneutron cross section are redone by using the determined -ray strength function via the NLD models. The Constant Temperature Model (CTM), Back Shifted Fermi Gas Model (BSFGM) and Generalized Superfluid Model (GSM) are preferred to use in NLD calculations. The predictions are compared with each other and the available experimental data. EXFOR library is used to take all experimental data.