Neutron Productions from thin Be target irradiated by 50 MeV/u ²³⁸U beam

¹ Pohang Accelerator Laboratory, POSTECH, Pohang 37673, Republic of Korea
² Division of Advanced Nuclear Engineering, POSTECH, Pohang 37673, Republic of Korea
³ Institue of Technology, Shimizu Corporation, Tokyo, Japan
⁴ RIKEN, Wako, Japan

^* Corresponding Author, E-mail: lee@postech.ac.kr

Published online: 25 September 2017

Abstract

Neutrons generated from thin beryllium target by 50 MeV/u ²³⁸U beam were measured using activation analysis at 15, 30, 45, and 90 degrees from the beam direction. A 0.085 mm-thick Be stripper of RIBF was used as the neutron generating target. Activation detectors of bismuth, cobalt, and aluminum were placed out of the stripper chamber. The threshold reactions of ²⁰⁹Bi(n, xn)^210-xBi(x=4~8), ⁵⁹Co(n, xn)^60-xCO(x=2~5), ⁵⁹Co(n, 2nα)⁵⁴Mn, ²⁷Al(n, α)²⁴Na, and ²⁷Al(n,2nα)²²Na were applied to measure the production rates of radionuclides. The neutron spectra were obtained using an unfolding method with the SAND-II code. All of production rates and neutron spectra were compared with the calculated results using Monte Carlo codes, the PHITS and the FLUKA. The FLUKA results showed better agreement with the measurements than the PHITS. The discrepancy between the measurements and the calculations were discussed.