1205.0265 (H. Matsumura et al.)

Shielding Experiments Under JASMIN Collaboration at Fermilab(III) -
Measurement of High-Energy Neutrons Penetrating a Thick Iron Shield from the
Antiproton Production Target by AU Activation Method    [PDF]

H. Matsumura, N. Kinoshita, H. Iwase, A. Toyoda, Y. Kasugai, N. Matsuda, Y. Sakamoto, H. Nakashima, H. Yashima, N. Mokhov, A. Leveling, D. Boehlein, K. Vaziri, G. Lautenschlager, W. Schmitt, K. Oishi

In an antiproton production (Pbar) target station of the Fermi National Accelerator Laboratory (FNAL), the secondary particles produced by bombarding a target with 120-GeV protons are shielded by a thick iron shield. In order to obtain experimental data on high-energy neutron transport at more than 100-GeV-proton accelerator facilities, we indirectly measured more than 100-MeV neutrons at the outside of the iron shield at an angle of 50{\deg} in the Pbar target station. The measurement was performed by using the Au activation method coupled with a low-background {\gamma}-ray counting system. As an indicator for the neutron flux, we determined the production rates of 8 spallation nuclides (196-Au, 188-Pt, 189-Ir, 185-Os, 175-Hf, 173-Lu, 171-Lu, and 169-Yb) in the Au activation detector. The measured production rates were compared with the theoretical production rates calculated using PHITS. We proved that the Au activation method can serve as a powerful tool for indirect measurements of more than 100-MeV neutrons that play a vital role in neutron transport. These results will be important for clarifying the problems in theoretical calculations of high-energy neutron transport.

View original: http://arxiv.org/abs/1205.0265