Activation detector measurements at the hadron absorber of the NuMI neutrino beamline at Fermilab

Two-dimensional distributions of the production rates of radionuclides in aluminum and gold activation detectors, placed behind the hadron absorber of the NuMI beamline at Fermilab were obtained in an experiment for shielding data as a dump in a proton-beam-energy domain above 100 GeV. The production rates of 7 Be, 22 Na, and 24 Na in the aluminum activation detectors and those of 185 Os, 194 Au, and 196 Au in the gold activation detectors were obtained from the γ-ray spectra of HPGe counters. It was concluded that in these distributions showed some peaks that can be attributed to a lack of shielding caused by the gaps for arraignment and cooling in the hadron absorber. The radionuclides in the activation detectors were mainly produced by neutrons, protons and pions, according to analyses of calculated results by the PHITS code

Shielding experiments by the JASMIN collaboration at Fermilab (II) - Radioactivity measurement induced by secondary particles from the anti-proton production target

The JASMIN Collaboration has performed an experiment to conduct measurements of nuclear reaction rates around the anti-proton production (Pbar) target at the Fermi National Accelerator Laboratory (FNAL). At the Pbar target station, the target, consisting an Inconel 600 cylinder, was irradiated by a 120 GeV/c proton beam from the FNAL Main Injector. The beam intensity was 3.6 x 10{sub 12} protons per second. Samples of Al, Nb, Cu, and Au were placed near the target to investigate the spatial and energy distribution of secondary particles emitted from it. After irradiation, the induced activities of the samples were measured by studying their gamma ray spectra using HPGe detectors. The production rates of 30 nuclides induced in Al, Nb, Cu, Au samples were obtained. These rates increase for samples placed in a forward (small angle) position relative to the target. The angular dependence of these reaction rates becomes larger for increasing threshold energy. These experimental results are compared with Monte Carlo calculations. The calculated results generally agree with the experimental results to within a factor of 2 to 3