Verification of the surrogate ratio method

Chiba, Satoshi; Iwamoto, Osamu  

Effects of difference in the spin and parity distributions for the surrogate and neutron-induced reactions are investigated. It was found that the surrogate ratio method can be employed to determine neutron fission and capture cross sections if (1) weak Weisskopf-Ewing condition (defined in this paper) holds, (2) spin-parity distributions of the decaying nuclei in the 2 surrogate reactions are equivalent to each other, and (3) difference of the representative spin values between the neutron-induced and surrogate reactions is within the order of 10 . Achievable accuracy is estimated to be around 5 and 10% for fission and capture channels, respectively. The surrogate absolute method, on the contrary, can be only marginally applicable to determination of fission cross sections.