Pages: 10-21

Authors: Le Tran Minh Nhat, Vu Duc Cong, Le Hong Khiem, Nguyen Thi Dinh, Pham Tien Thanh, Truong Hoai Bao Phi, Nguyen Thi Xuan Thai, Tran Ngoc Toan, Dinh Van Trung, Nguyen Thanh Binh, Nguyen An Son, Valery Nikolaevich Shetsov, Andrey Yuryevich Dmitriev, Valerij Vladimirovich Lobachev, and Sergey Borisovich Borzakov

Abstract

The determination of the characteristics of neutron spectrum at different irradiation positions on the outer wall of moderator chamber of the intense resonance neutron source by simulation method using MCNP code was presented. The characteristics of neutron spectrum including the flux of thermal, epithermal and fast neutron, neutron temperature and -shape parameter have been determined. For validation of MCNP simulation, the characteristics of neutron spectrum at the optimal irradiation position were determined experimentally by activation technique. The comparison shows that the simulated and experimental results are in agreement, which indicates the high reliability of MCNP code except for -shape parameter. Our revised equation for determination of  shape parameter by the method of cadmium-ratio for multi-monitor has been used, in which the correction coefficients of the epithermal neutron transmission for cadmium cover, the thermal and epithermal neutron self-shielding, were included for improvement of the accuracy. The calculated and measured -shape parameters are in good agreement when our proposed

Key words: intense resonance neutron source, neutron spectrum characterization, MCNP, activation method

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