Evaluation of the /sup 63/Cu activation foil for determining the neutron dose in the energy range of 1 eV to 1 MeV

Abstract

The appropriateness of the Cu activation foil for determining the neutron dose in the energy region from 1 eV to 1 MeV has been investigated for spectra of seven different criticality accident configurations. A program was written for folding the published spectra with the Cu activation cross sections and with the fluence-to-dose or kerma conversion factors. It is shown that for these spectra the neutron dose and kerma result primarily from the energy region above 15 keV whereas the measured Cu activity is mainly determined by the fluence in the region between 1 eV and 15 keV. Uncertainties in the fluence spectrum in the low-energy region between 1 eV and 15 keV, which in reality do not affect the dose contribution, might 6k lead to large deviations in the measured Cu activity and hence to the derived dose in the 1 eV to 1 MeV range. Use of 10 B shielding for attenuating the fluence in the 1-eV to 15-keV region was evaluated, leading to the conclusion that the necessary amount of boron material is unacceptably large and would appreciably increase the cost of the dosimeter currently used at Los Alamos. The lower limit of neutron detectability would also be increased.

Personal nuclear accident dosimetry at Sandia National Laboratories

“…Neutron dose and kerma (in tissue) result primarily from neutrons in the energy region above 15 keV, w h e r d c u activity is mainly determined by the neutron fluence in the region between 1 eV and 15 keV. Uncertainties in the fluence spectrum in the region between 1 eV and 15 keV may lead to large deviations in the measuredaCu activity and, therefore in the derived dose (Eisen et al, 1985). The sensitivity of the copper foil to neutrons of thermal and epithermal energies can, however, be used.…”

Characterization of a nuclear accident dosimeter

“…After evaluating this data for the copper foil, a report (Eisen et al 1985) which investigated the problem with using copper foils for dose determination was discovered.…”