Measurement of fission cross section for ²³²Th (n,f) ¹³¹ _ZX ( Z = 50 , 51, 52, 53) reaction induced by neutrons around 14 MeV

Abstract.

The fission cross sections of ²³²Th (n,f) ^{131m, g}Sn , ²³²Th (n,f) ¹³¹Sb , ²³²Th (n,f) ^{131m, g}Te , ²³²Th (n,f) ¹³¹I fission reactions induced by 14MeV neutrons were measured precisely with the neutron activation technique. The neutron flux was monitored by accompanying $\alpha$ particle in the irradiation and the neutron energies were determined by the cross section ratio of ⁹⁰Zr (n,2n) ⁸⁹Zr to ⁹³Nb (n,2n) ^92mNb reaction. The values of the cross sections of ²³²Th (n,f) ^{131m, g}Sn were analyzed, and the cross sections of ²³²Th (n,f) ¹³¹Sb were deduced to be $6.5\pm 0.7$ , $6.3\pm 0.6$ , $6.1\pm 0.6$ mb at $14.1\pm 0.3$ , $14.5\pm 0.3$ and $14.8\pm 0.3$ MeV, respectively. The values of the cross sections of ²³²Th (n,f) ^131gTe were deduced to be $1.8\pm 0.1$ , $1.5\pm 0.1$ and $1.4\pm 0.1$ mb at $14.1\pm 0.3$ , $14.5\pm 0.3$ and $14.8\pm 0.3$ MeV, respectively. The values of the cross sections of ²³²Th (n,f) ¹³¹I were given as $1.8\pm 0.2$ , $1.6\pm 0.2$ , $1.5\pm 0.1$ mb at $14.1\pm 0.3$ , $14.5\pm 0.3$ and $14.8\pm 0.3$ MeV, respectively.