Measurements of LET Distribution and Dose Equivalent onboard the Space Shuttle IML-2 (STS-65) and S⁄MM#4 (STS-79)

Takayoshi Hayashi; Tadayoshi Doke; Jun Kikuchi; Takao Sakaguchi; Ryuichi Takeuchi; Takeshi Takashima; Masanori Kobayashi; Kazuhiro Terasawa; Kenichi Takahashi; Atsushi Kyan; Nobuyuki Hasebe; Toshisuke Kashiwagi; Koichi Ogura; Shunji Nagaoka; Mitsuyasu Kato; Tamotsu Nakano; Shimpei Takahashi; Hisashi Yamanaka; Katsumi Yamaguchi; Gautam D. Badhwar

doi:10.2187/bss.11.355

Takayoshi Hayashi, Tadayoshi Doke, Jun Kikuchi, Takao Sakaguchi, Ryuichi Takeuchi, Takeshi Takashima, Masanori Kobayashi, Kazuhiro Terasawa, Kenichi Takahashi, Atsushi Kyan, Nobuyuki Hasebe, Toshisuke Kashiwagi, Koichi Ogura, Shunji Nagaoka, Mitsuyasu Kato, Tamotsu Nakano, Shimpei Takahashi, Hisashi Yamanaka, Katsumi Yamaguchi, Gautam D. Badhwar

Author information

Takayoshi Hayashi
Advanced Research Center for Science and Engineering, Waseda University, Okubo 3-4-1, Shinjuku-ku, Tokyo 169, Japan;
Tadayoshi Doke
Advanced Research Center for Science and Engineering, Waseda University, Okubo 3-4-1, Shinjuku-ku, Tokyo 169, Japan;
Jun Kikuchi
Advanced Research Center for Science and Engineering, Waseda University, Okubo 3-4-1, Shinjuku-ku, Tokyo 169, Japan;
Takao Sakaguchi
Advanced Research Center for Science and Engineering, Waseda University, Okubo 3-4-1, Shinjuku-ku, Tokyo 169, Japan;
Ryuichi Takeuchi
Advanced Research Center for Science and Engineering, Waseda University, Okubo 3-4-1, Shinjuku-ku, Tokyo 169, Japan;
Takeshi Takashima
Advanced Research Center for Science and Engineering, Waseda University, Okubo 3-4-1, Shinjuku-ku, Tokyo 169, Japan;
Masanori Kobayashi
Advanced Research Center for Science and Engineering, Waseda University, Okubo 3-4-1, Shinjuku-ku, Tokyo 169, Japan;
Kazuhiro Terasawa
Advanced Research Center for Science and Engineering, Waseda University, Okubo 3-4-1, Shinjuku-ku, Tokyo 169, Japan;
Kenichi Takahashi
Advanced Research Center for Science and Engineering, Waseda University, Okubo 3-4-1, Shinjuku-ku, Tokyo 169, Japan;
Atsushi Kyan
Advanced Research Center for Science and Engineering, Waseda University, Okubo 3-4-1, Shinjuku-ku, Tokyo 169, Japan;
Nobuyuki Hasebe
Department of Computer Science, Ehime University, Bunkyo-cho 3, Matsuyama, Ehime 790, Japan;
Toshisuke Kashiwagi
Department of Business and Engineering, Kanagawa University, Rokkakubashi 3-27-l, Kanagawa-ku, Yokohama 221, Japan;
Koichi Ogura
College of Industrial Technology, Nihon University, Izumi-cho 1-2-1, Narashino, Chiba 275, Japan;
Shunji Nagaoka
Tsukuba Space Center, NASDA, Sengen 2-1-1, Tsukuba, Ibaraki 305, Japan;
Mitsuyasu Kato
Tsukuba Space Center, NASDA, Sengen 2-1-1, Tsukuba, Ibaraki 305, Japan;
Tamotsu Nakano
Tsukuba Space Center, NASDA, Sengen 2-1-1, Tsukuba, Ibaraki 305, Japan;
Shimpei Takahashi
Tsukuba Space Center, NASDA, Sengen 2-1-1, Tsukuba, Ibaraki 305, Japan;
Hisashi Yamanaka
Japan Space Utilization Promotion Center, Nishiwaseda 3-30-16, Shinjuku-ku, Tokyo 169, Japan; and
Katsumi Yamaguchi
Japan Space Utilization Promotion Center, Nishiwaseda 3-30-16, Shinjuku-ku, Tokyo 169, Japan; and
Gautam D. Badhwar
NASA Johnson Space Center, Houston, TX 77058, U.S.A.

JOURNAL FREE ACCESS

1997 Volume 11 Issue 4 Pages 355-364

DOI https://doi.org/10.2187/bss.11.355

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Abstract

Space radiation dosimetry measurements have been made onboard the Space Shuttle STS-65 in the Second International Microgravity Laboratory (IML-2: 28.5° x 300 km: 14.68 days) and the STS-79 in the 4th Shuttle MIR mission (S⁄MM#4: 51.6° x 300-400 km: 10.2 days). In these measurements, three kinds of detectors were used; one is a newly developed active detector telescope called “Real-time Radiation Monitoring Device (RRMD-I for IML-2 and RRMD-II with improved triggering system for S⁄MM#4)“ utilizing silicon semi-conductor detectors and the other detectors are conventional passive detectors of thermoluminescence dosimeters (TLDs) and CR-39 plastic track detectors. The main contribution to dose equivalent for particles with LET > 5.0 keV⁄μm(IML-2) and LET>3.5. keV⁄μm (S⁄MM#4) is seen to be due to galactic cosmic rays (GCRs) and the contribution of the South Atlantic Anomaly (SAA) is less than 5%(IML-2: 28.5° x 300 km) and 15% (S⁄MM#4: 51.6° x 400 km) in the above RRMD LET detection conditions. For the whole LET range (> 0.2 keV⁄μm) obtained by TLDs and CR-39 in these two typical orbits (a small inclination x low altitude and a large inclination x high altitude), absorbed dose rates range from 94 to 114 μGy⁄day, dose equivalent rates from 186 to 207μSv⁄day and average quality factors from 1.82 to 2.00 depending on the locations and directions of detectors inside the Spacelab at the highly protected IML-2 orbit (28.5°x 300 km) , and also, absorbed dose rates range from 290 to 367 μGy⁄day, dose equivalent rates from 582 to 651 μSv⁄day and average quality factors from l.78 to 2.01 depending on the dosimeter packages around the RRMD-II “Detector Unit” at the S⁄MM#4 orbit (51.6° x 400 km). In general, it is seen that absorbed doses depend on the orbit altitude (SAA trapped particles contribution dominant) and dose equivalents on the orbit inclination (GCR contribution dominant). The LET distributions obtained by two different types of active and passive detectors, RRMDs and CR-39, are in good agreement for LET of 15 - 200 keV⁄μm and difference of these distributions in the regions of LET<15 keV/μm and LET >200 keV⁄μm can be explained by considering characteristics of CR-39 etched track formation especially for the low LET tracks and chemical etching conditions.

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