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About 200 Japanese domestic flights between Haneda(Tokyo) and Matsuyama were examined to find the dose due to cosmic radiation. As the dose fluctuated by roughly 25% around the mean, we may need some room in considering the legal scheme to suppress the dose.

The phoswich neutron detector was completed and experiments were made to measure neutron spectrum in a neutron and proton mixed radiation field. The phoswich neutron detector has been improved for high-energetic neutron measurement onboard aircrafts and spacecrafts. The detector is composed of a harmless and biodegrable liquid scintillator, a slow plastic scintillator and a short photomultiplier tube. A pulse shape is captured with data acquisition board. To confirm collected signal and define particle discrimination parameter, a pulse shape is also acquired with a digital storage ocilloscope

At a time when manned space exploration is more a reality with the planned the International Space Station (ISS) well underway, the biological effects for chronically low-dose (rate) irradiation in the field of low-flux galactic cosmic rays (GCR) have become one of the major concerns of space science. It is, therefore, important to estimate radiation risk in human body of high-energy & charged (HZE) particles, especially secondary scattered radiation field produced by the interaction between heavy ions and structural materials of a space station etc.In this study we designed an experimental field for chronically low-dose irradiation of secondary radiation scattered with heavy-ion radiation field and examined cellular responses in the field.

第2回International Workshop on Space Radiation Research（2002年3月11-15日、奈良）で発表された内容の論文集

The Mobile Radiation Exposure Control System's (Liulin-4 type) main purpose is to monitor simultaneously the doses and fluxes at 4 independent places. It can also be used for personnel dosimetry. The system consists of 4 battery-operated 256-channel dosimeters-spectrometers. We describe results obtained during the calibrations of the spectrometers at the Cyclotron facilities of the University of Louvain, Belgium and of the National Institute of Radiological Sciences-STA, Chiba, Japan with protons of energies up to 70 MeV. The angular sensitivities of the devices are studied and compared with Monte-Carlo predictions. We also present the results obtained at the HIMAC accelerator with 500 MeV/u Fe ions. Records made during airplane flights are shown and compared with the predictions of the CARY-3 model.

The 2nd and 3rd ICCHIBAN (Inter-Comparison for Cosmic-ray with Heavy Ion Beams At NIRS) runs were performed in May, 2002 and Feb., 2003 and included the participation of many Japanese and international researchers. The principle objective of this program is the ground-based intercomparison of different radiation monitors which are routinely used or are planned to be used to measure the exposure of space crews to ionizing radiation aboard the International Space Station (ISS) and the NASA Space Shuttles. The 2nd and 3rd ICCHIBAN run were dedicated to the intercomparison of passive detectors and active detectors, respectively. The results measured by the different instruments were gathered together and are being investigated by the ICCHIBAN working group.

On 28-30 Sept. 2004 ICCHIBAN intercomparison experiments were performed at NASA Space Radiation Laboratory (NSRL), Brookheven National Laboratory (BNL), USA. The NSRL facility was constructed to irradiate biological samples and physical instruments with high energy heavy ion and proton beams. Using 1 GeV proton, 1 GeV Oxgen and 1GeV Iron beams, instruments and dosimeters for space radiation dosimetery were investigated for their responses to these artificial radiation sources. Around 20 researchers performed these experiments by themselves and ICCHIBAN Working Group (ICWG) performed exposures to passive dosimeters from totally 15 institutions. We report outlook of these experiments briefly. \nAfter this workshop the ICCHIBAN-7 and -8 (IC-7 & -8) experiments will be performed using the HIMAC. IC-7 is dedicated to the intercomparison of active instruments and IC-8 is dedicated to the intercomparison of passive dosimeters. Participants include both laboratories that have participated in previous ICCHIBAN experiments as well as a number of first time participants. For IC-7 400 MeV/nucleon Oxygen and 300 MeV/nucleon Iron will be provided in the HIMAC PH2 beam course. For IC-8 Helium 150 MeV/nucleon, 400 MeV/nucleon Oxygen, 500 MeV/nucleon Argon and 200 MeV/nucleon Fe will be provided in the HIMAC BIO exposure room. The current status of reporting of results from previous ICCHIBAN experiments as well as the future ICCHIBAN experiments will also be discussed., 10th WRMISS

The EUSO telescope will be irradiated with space radiation for 5 years while on a low earth orbit. Many parts of the telescope are of a new design and have no data regarding radiation damage. In order to investigate the effects of radiation damage to the electric parts while in a low earth orbit, photodetector modules (PDM) and glass windows for the Multi-Anode Photo-Multiplier Tubes (MAPMT) in the telescope were irradiated with medium energy (70 MeV) proton beams from an accelerator at the National Institute of Radiological Sciences (NIRS) in Japan. Based on these results, the capability of these parts when exposed to an actual space radiation environment after 5 years can be estimated., 29th International Cosmic Ray Conference

Measurements of space radiation in aircrafts performed in many domestic and international routes. The measurements have been done using NaI Scintillation Spectrometers and LiI Scintillation Spectrometer. There are two types of NaI Scintillation Counters which are 3 inches spherical scintillator and 2 inches cylindrical scintillator which were developed Riken in Japan. One is surrounding LiI scintillation counter, a 5 inches polystyrene sphere is located. Because of this polystyrene sphere, high energy neutrons are moderated to thermal neutrons and the thermal neutrons are converted to 4He and 3H particles and recorded high deposit energy in the LiI scintillation counter. The other is used 2 inches NaI Detector with GPS system. Intensities of space radiation in aircrafts at high altitude can be measured. The ratios of charged particles which were measured in NaI SC and neutron which were measured LiI SC were correlated the altitude of aircraft and geomagnetic latitude. Using Liulin-4J silicon spectrometers which were developed in Bulgaria, a part of charged particles could be observed. The results from Liulin-4J can be compared our NaI SC and LiI Sc. We report these data in many domestic and international routes and results of comparison of these detectors and estimated doses by simulation codes., AOGS, 2nd Annual Meeting 2005

6th International Conference onHigh Levels of Natural Radiation and Radon Areas

9th Workshop on Radiation Monitoring for the International Space Station

The ICCHIBAN-3 experiment for active space radiation detectors was conducted in February 2003. Five active radiation detectors from four countries, plus a ground-based charged particle spectrometer and several passive detectors were exposed to heavy ion beams at the NIRS HIMAC. The heavy ion beams consisted of 800 MeV/n 28Si, 500 MeV/n 56Fe and 400 MeV/n 12C. The comparison results from active detector exposures during the ICCHIBAN-3 experiment are reported. \nThe ICCHIBAN-5 experiment for active space radiation detectors was performed in February 2004. Six active detectors from five countries were exposed to heavy ion beams in Biology Exposure Room of HIMAC. Wide (10 cm diameter), uniform beams were used to ensure that the entire sensitive area of each detector was exposed. The current status of the analysis of these exposures are presented., 9th WRMISS Workshop

Intercomparison experiments (ICCHIBAN) for space radiation dosimetry instruments with heavy ion beams at HIMAC in NIRS have been performed for three years, starting in Feb. 2002. These experiments were performed with the participation of 16 space agencies, institutes and universities in 10 nations. The experiments are dedicated to calibrate and intercompare the response of instruments to radiation of charge and energy found in the space environment and to aid in understanding and resolving discrepancies in past space radiation dosimetric measurements. This paper summarizes results obtained from the ICCHIBAN-3 and ICCHIBAN-4 experiments. This ICCHIBAN project has been extended from the NIRS HIMAC to include the experiments at the Loma Linda Univeristy Medical Center in California using proton beams and the NASA Space Radation Laboratory at the Brookhaven National Laboratory in New York for higher energy and charged particle beams., 35th Scientific Assemly

35th Scientific Assemly

14th International Conference on Solid State Dosimetry

11th International Congress of the International Radiation Protection

3rd International Workshop on Space Radiation Research & 15th Annual NASA Space Radiation Health Investigators' Workshop

The ICCHIBAN intercomparison experiments for space radiation instruments using ion beams from accelerators have been performed at HIMAC, Chiba, Japan and Loma Linda Univ. Medical Center (LLUMC), California, USA. Investigators from 17 laboratories in 10 nations participated in these experiments. To date, five intercomparison experiments have performed at HIMAC using heavy ion beams, including He, C, Ne, Si, Ar and Fe, that are of importance in the galactic cosmic-ray spectrum. At LLUMC, an experiment was performed using a proton beam to simulate a solar particle event. Additional experiments, including an intercomparison using relativistic Fe, Si and proton beams at NSRL, are currently being planned. The objectives of the ICCHIBAN intercomparison experiments are to 1) determine the response of space radiation instruments to heavy ions and protons; 2) intercompare the response and sensitivity of these instruments; 3) establish and characterize an accelerator-based "reference standard" against which these instruments can be calibrated. The participants of ICCHIBAN-1 and ICCHIBAN-2 experiments have analyzed their results and submitted reports to the ICCHIBAN working group (ICWG). ICWG has summarized the results and published as HIMAC Technical Report. For active instruments, the LET distributions from instruments using Si detectors and from TEPC were good agreement for 12C exposures, although the width of the main peak was broader for the TEPC exposures due to differences in the operating principles of the instruments. Several active instruments were found to lack sensitivity to high LET particles including the Fe beam used in the intercomparison. For passive dosimeters, ICWG exposed participants' dosimeters to both 'known' and 'blind' conditions. The participants analyzed their dosimeters from the 'known' exposures to measure dose linearity and obtain high-LET dose efficiency response. In the blind exposure simulating an actual exposure in space (97% low LET particles and 3% high LET particles) most of dosimeters showed good agreement with the reference ion chamber measurements. But, in other blind exposures where high LET radiation was dominant, there was larger disagreement. This was largely due to the lack of efficiency of TLD and OSL dosimeters in registering dose from high-LET particles. Some of participants applied correction methods to the TLD or OSL data that greatly improved their response to high-LET particles. Only those passive detector laboratories that used a combination of CR-39 PNTD and TLD were able to measure both dose and dose equivalent., 3rd International Workshop on Space Radiation Research

Planning long durations missions to Mars or a return to the moon has increased the importance of reliable radiation measurements for crew dosimetry. However at present, results from several radiation detectors do not agree with one another. In order to make sure that there is good agreement amongst space radiation detectors, especially for the high-LET galactic cosmic ray component, and in order to establish a standard heavy ion calibration for space radiation detectors, an intercomparison program called ICCHIBAN (InterComparison Cosmic-ray with Heavy Ion Beams At NIRS) Project was started in 2002. Since February 2002, two experiments for active detectors and two experiments for passive detectors have been performed with over 70 investigators participating. For active detectors, a 2 cm diameter, well characterized beam is used to expose each detector under identical conditions. For passive detectors, a 10 cm flattened beam is used for the exposures. The results from 1st and 2nd ICCHIBAN experiments are reported and analyzed in detail. The methodology and results of 1st to 4th ICCHIBAN run and future plans of the ICCHIBAN project are shown., COSPAR COLLOQUIUM, "Radiation Safety for Manned Mission to Mars "

In the 1st and 3rd ICCHIBAN (InterComparison for Cosmic-ray with Heavy Ion Beams At NIRS) experiments, we performed an intercomparison of the response of active detectors used in space radiation dosimetry to heavy ion beams at the NIRS HIMAC. Detectors which were irradiated during these experiments included the NASDA RRMD-III, the IV-CPDS, ISS-TEPC and Shuttle-TEPC from NASA-JSC, the U. of Kiel DOSTELs, the Liulin-4J of STIL-BAS and NIRS and a number of passive detectors. Since several of these detectors had not been previously irradiated to high energy heavy ion beams, the ICCHIBAN-1 and 3 exposures were the first attempts to systematically investigate their response in the high LET region. These experiments are significant for space radiation dosimetry because not only silicon detectors but also two tissue equivalent proportional counters were included. Based on the participants reports for the ICCHIBAN-1 experiment, we have compared the results from the different instruments. This comparison, together with initial results from the ICCHIBAN-3 experiment, will be presented. In addition, information regarding the 5th ICCHIBAN experiment will be announced., 8th WRMISS Workshop

Genomic Instability in Mutation Induction on Normal Human Fibroblasts Irradiated with Chronic Low-dose Radiations in Heavy-ion Radiation Field \nMasao Suzuki, Chizuru Tsuruoka, Yukio Uchihori, Hiroshi Yasuda and Kazunobu Fujitaka \nInternational Space Radiation Laboratory, National Institute of Radiological Sciences, 4-9-1 Anagawa, Chiba 263-8555, Japan. \nAt a time when manned space exploration is more a reality with the planned the International Space Station (ISS) underway, the potential exposure of crews in a spacecraft to chronic low-dose radiations in the field of low-flux galactic cosmic rays (GCR) and the subsequent biological effects have become one of the major concerns of space science. We have studied both in vitro life span and genomic instability in cellular effects in normal human skin fibroblasts irradiated with chronic low-dose radiations in heavy-ion radiation field. Cells were cultured in a CO2 incubator, which was set in the irradiation room for the biological study of heavy ions in the Heavy Ion Medical Accelerator in Chiba (HIMAC) at National Institute of Radiological Sciences (NIRS), and irradiated with scattered radiations produced from heavy ions. Absorbed dose measured using a thermoluminescence dosimeter (TLD) and a Si-semiconductor detector was to be around 1.4 mGy per day when operating the HIMAC machine for biological experiments. The total population doubling number (tPDN) of low-dose irradiated cells was significantly smaller (79-93%) than that of unirradiated cells. The results indicate that the life span of the cell population shortens by irradiating with low-dose scattered radiations in the heavy-ion irradiation field. Genomic instability in cellular responses was examined to measure either cell killing or mutation induction in low-dose accumulated cells after exposing to X-ray challenging doses. The results showed that there was no enhanced effect on cell killing between low-dose accumulated and unirradiated cells after exposing to defined challenging doses of 200kV X rays. On the contrary, the mutation frequency on hprt locus of low-dose accumulated cells was much higher than that of unirradiated cells. The results suggested that genomic instability was induced in mutagenesis by the chronic low-dose irradiations in heavy-ion radiation field., 12th International Congress of Radiation Research

One of the conclusions of the annual Workshops on Radiation Monitoring for the International Space Station (WRMISS) is a recommendation that radiation instruments used aboard the International Space Station for crew dosimetry need to be intercompared in well characterized ground based radiation fields. Following this recommendation, we have initiated a project called the InterComparison for Cosmic ray with Heavy Ion Beams At NIRS (ICCHIBAN) using heavy ion beams at the HIMAC accelerator in NIRS, Japan. On February, 2002, the first set of intercomparison exposures (1st ICCHIBAN run) devoted to active instruments was carried out using 400MeV/u Carbon and 400MeV/u Iron beams. Subsequently, we have performed the 2nd ICCHIBAN run for passive detectors using Helium, Carbon, Silicon and Iron beams in May 2002. We report the methodologies of the exposures and preliminary results of the intercomparison for the active detectors and passive detectors., 34th Scientific Assembly

The first two sets of controlled exposures of space radiation detectors to heavy ions at the HIMAC were successfully carried out as part of the ICCHIBAN (InterComparison for Cosmic Rays with Heavy Ion Beams At NIRS) Project. The first ICCHIBAN run, dedicated to the intercomparison of active detectors, was conducted in February 2002. Detectors from eight different institutions, including two NASA JSC TEPCs, the NASA JSC CPDS, the DLR DOSTEL Si telescope, the NASDA RRMD-III Si telescope, and the Liulin Mobile Dosimetry Unit were exposed to beams of 400 MeV/n Carbon and 400 MeV/n Iron. Reference measurements of the HIMAC beam were made using the LBNL Ground Base Detector. The second ICCHIBAN Run, dedicated to passive detectors, was carried out in May 2002 and included TLDs and PNTDs from ten different laboratories in Europe, Russia, the USA and Japan. Passive detectors were exposed to 150 MeV/n Helium, 400 MeV/n Carbon, 490 MeV/n Silicon, and 500 MeV/n Iron. Preparations are currently underway for the 3rd and 4th ICCHIBAN runs tentatively scheduled for February and May 2003., 7th WRMISS Workshop

The 2nd International Workshop on Space Radiation Research

The 13th International Conference on Solid State Dosimetry(SSD-2001)

The 13th International Conference on Solid State Dosimetry(SSD-2001)

The 13th International Conference on Solid State Dosimetry(SSD-2001)

13th SYmposium on Microdosimetry

The 2nd International Workshop on Space Radiation Research

The 2nd International Workshop on Space Radiation Research