A Method to Improve Dose Assessment by Reconstruction of the Complete Isotopes Inventory

Abstract

Radiation shielding assessments may underestimate the expected dose if some isotopes at trace level are not considered in the isotopes inventory of the shielded radioactive materials. Indeed, information about traces is not often available. Nevertheless, the activation of some minor isotopic traces may significantly contribute to the dose build-up. This paper presents a new method (Isotopes Inventory Reconstruction-IIR) estimating the concentration of the minor isotopes in the irradiated material at the beginning of the cooling period. The method requires the solution of the inverse problem describing the irradiated material's decay. In a mixture of an irradiated uranium-plutonium oxide shielded by a set-up made of stainless-steel, porous polyethylene plaster and lead methyl methacrylate, the comparison between different methods proves that the IIR-method allows better assessment of the dose than other approximate methods.

Intrinsic noise of a superheated droplet detector for neutron background measurements in massively shielded facilities

“…These detectors are traditionally used for personal neutron dosimetry [3,4], but have also been employed in high energy neutron spectrometry [5,6], registration of high and intermediate heavy ions [7] and direct search for dark matter [8,9]. At C 2 TN superheated droplet detectors (SDD) of 1-3 wt.% C 2 ClF 5 in a food gel-based matrix are developed and operated with an acoustic instrumentation for signal detection.…”