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

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 ²⁷Al, ${}^{\mathrm{nat}}$Si, ⁵⁹Co, 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 safe side in radioactivity estimation and needs to be corrected in the following three cases: (i) isomer production; (ii) radionuclide production by 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.