Estimation of systematic uncertainty in PHITS using bootstrap method

Hashimoto, Shintaro  ; Sato, Tatsuhiko   

Particle transport simulation code PHITS has been successfully applied to shielding calculations in accelerator facilities. We developed a function to estimate reliability of PHITS results as systematic uncertainty based on ANOVA (analysis of variance), where it is assumed that the results show a normal distribution. In this study, we applied the bootstrap method to analysis of non-normal distribution, which is rarely caused when uncertainty of nuclear reaction models has the biased distribution. The confidence interval estimated by the bootstrap method was more appropriate than that obtained by the assumption of the normal distribution for use as an indicator of the reliability of a PHITS result in a neutron shielding calculation. However, the interval by the bootstrap method was narrow compared to the distribution of the original result.