New analytical method to estimate systematic uncertainty in PHITS

Hashimoto, Shintaro  ; Sato, Tatsuhiko   

PHITS can simulate a behavior of various particles such as neutrons and photons, and has been used for shielding calculations in accelerator facilities. Reliability of PHITS based on the Monte Carlo method can be usually evaluated by statistical uncertainties related with the number of trials. However, uncertainty of input parameters such as densities and compositions of shielding materials might influence on results of the shielding calculation. Estimation of the influence as systematic uncertainties gives quantitative discussion of the calculation. We proposed a new method to estimate systematic uncertainties with ANOVA, and then applied the method to analysis of neutron shielding calculations. In the analysis, the effect of the uncertainty of water contents in concrete materials on neutron fluences could be estimated quantitatively.