A novel conceptualization in the analysis and design of passive neutron area monitors based on gold foil activation

Appl Radiat Isot. 2022 Mar:181:110110. doi: 10.1016/j.apradiso.2022.110110. Epub 2022 Jan 13.

Abstract

In the detection and measurement of neutron fields, with energies between 10 and 20 MeV, current passive neutron area monitors based on gold foil sensors usually do not have a perfect fitting of their dose response functions with the neutron fluence-to-ambient dose equivalent conversion function from ICRP74. However, apart from the radiative capture in 197Au, the common channel considered in these monitors, other nuclear reactions in 197Au can be considered to improve the fit between both functions. Therefore, this work aimed to develop a mathematical combination of response functions in passive monitors with gold foils, considering the (n, γ) and (n, 2n) channels in 197Au, to extend their response up to 20 MeV, improving their performance under neutron fields with high energies. The proposed methodology avoids introducing modifications in the original device, such as the insertion of sheets with high-Z materials, and simplifies the design and manufacturing of passive monitors, while reducing costs.

Keywords: Gold foil activation; MCNP6; Neutron area monitor; Passive detector; Response function.