Evaluation of dose rate reduction in a spacecraft compartment due to additional water shield

Sato, Tatsuhiko   ; Niita, Koji*; Shurshakov, V. A.*; Yarmanova, E. N.*; Nikolaev, I. V.*; Iwase, Hiroshi*; Sihver, L.*; Mancusi, D.*; Endo, Akira   ; Matsuda, Norihiro  ; Iwamoto, Yosuke   ; Nakashima, Hiroshi; Sakamoto, Yukio; Yasuda, Hiroshi*; Takada, Masashi*; Nakamura, Takashi*

HZE particle transport codes are the indispensable tool in the shielding design of spacecrafts. We are therefore developing a general-purpose Monte Carlo code PHITS, which can deal with the transports of all kinds of hadrons and heavy ions with energies up to 200 GeV/n in 3-dimensional phase spaces. The applicability of PHITS to space researches has been well verified by comparing the neutron spectra in spacecrafts calculated by the code with the corresponding experimental data. Recently, PHITS was employed in the estimation of radiation fields in the Russian Service Module in ISS. The results of the estimation indicate that PHITS can reproduce experimental data of the dose reduction rates due to water shielding attached on the wall of the Russian crew cabin fairly well. The details of the calculation procedures will be given in the presentation, together with the results of other applications of PHITS to the space exploration.