Measurement of radionuclide production probabilities in negative muon nuclear capture and validation of Monte Carlo simulation model

TL;DR

This study measures radionuclide production probabilities from negative muon capture on various targets, validating and suggesting corrections for Monte Carlo simulation models used in radioactivity calculations.

Contribution

It provides new experimental data on radionuclide production probabilities and identifies specific areas where simulation models need correction.

Findings

Probabilities generally align with simulations but require corrections for isomer and multiple neutron emissions.

Expanded validation scope to processes outside existing data coverage.

Identified specific cases where Monte Carlo models need adjustments.

Abstract

As part of the development of a sample radioactivity calculation program, we have measured radionuclide production probabilities in negative muon nuclear capture to update experimental data and to validate a calculation dataset obtained by a Monte Carlo simulation code. The probabilities have been obtained by an activation experiment on $^{27}$Al, $^\mathrm{nat}$Si, $^{59}$Co, and $^\mathrm{nat}$Ta targets. The obtained probabilities expand the validation scope to the radionuclide production processes outside of the existing data coverage. By comparing the resultant probabilities with the calculated dataset, it has been revealed that the dataset is generally on the {\color{black}safe} side in radioactivity estimation and needs to be corrected in the following three cases: (i) isomer production; (ii) radionuclide production by the multiple neutron emission; (iii) radionuclide production by particle emissions involving a proton. The present probabilities and the new findings on the correction provide valuable clues to improvements of the simulation models.