Effect of Using Different Data Libraries and Simulation Codes on the Calculation of Spectra and Operational Quantities for the D₂O-²⁵²Cf Source at PTB

Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig, Germany

^* Corresponding author: amer.al-qaaod.ext@ptb.de

Published online: 11 April 2022

Abstract

The neutron reference field produced by a heavy-water moderated ²⁵²Cf source is used at PTB for calibrating neutron-measuring devices. Knowledge of the precise neutron spectrum is very important for the investigation of operational radiation protection quantities. Recently, new fission spectrum data of ²⁵²Cf has been proposed based on the latest nuclear data library version. At PTB, earlier calculations for the D₂O moderated ²⁵²Cf neutron source were carried out more than 20 years ago, thus updated and more detailed calculations are required. In this paper, a detailed simulation model of the PTB moderated ²⁵²Cf source assembly has been prepared and investigated using new spectral data and two different Monte Carlo transport codes MCNP6.1 and PHITS3.22, with ENDF/BVIII.0, ENDF/B-VII.1, ENDF/B-V, and ENDL85 evaluated nuclear data libraries. The results show that the evaluated nuclear data libraries influence the calculated operational quantities by (3-5) %. The dosimetric quantities calculated with the PHITS code and the ENDF/B-VII.1 data library agree well with the MCNP6 results.