title: Simulation of the low-Earth-orbit dose rates using secondary radiations from the HZE particles at NIRS-HIMAC.
abstract: In order to study biological effects from cyclic dose rates encountered at the low-Earth orbit (LEO), an experimental facility was designed in the Biology room of the Heavy Ion Medical Accelerator in Chiba (NIRS-HIMAC). An incubator placed in this facility is irradiated repeatedly by secondary radiations from HZE-particle beams supplied for independent users. The daily-average dose rate (1.4 mGy d-1) measured for 223 days and short-term dose rates measured for selected beam conditions were comparable to the dose rates observed in past LEO missions. Severe solar particle events can be simulated with hourly maximum dose rate of 2.8 mGy h-1. Preliminary measurements using CR-39 and TLD indicated that the dominant LET range is less than 5 keV micrometers-1. These results demonstrate the possibility of this facility for radiobiology studies of the effects of low dose rates comparable to the LEO environment.
authors.affiliation: International Space Radiation Laboratory (iSRL), National Institute of Radiological Sciences Inage-ku, Chiba, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Yasuda
authors.forename: M
authors.initials: M
authors.lastname: Suzuki
authors.forename: K
authors.initials: K
authors.lastname: Ando
authors.forename: K
authors.initials: K
authors.lastname: Fujitaka
mesh_terms: D002588:Cesium Radioisotopes; D003359:Cosmic Radiation; D018534:Earth, Planet; D005118:Extraterrestrial Environment; D018499:Linear Energy Transfer; D010315:Particle Accelerators; D010969:Plastics; D011092:Polyethylene Glycols; D011829:Radiation Dosage; D011834:Radiation Monitoring; D011853:Radiobiology; D019445:Solar Activity; D013026:Space Flight; D013819:Thermoluminescent Dosimetry
chemical_list: D002588:Cesium Radioisotopes; D010969:Plastics; C028827:CR 39; D011092:Polyethylene Glycols