2004 Fiscal Year Final Research Report Summary
Precise measurement of ultra-heavy nuclei in cosmic rays
| Project/Area Number |
13440080
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
素粒子・核・宇宙線
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| Research Institution | Waseda University |
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Principal Investigator |
HASEBE Nobuyuki Waseda University, Advanced Research Institute for Science and Engineering, Professor, 理工学総合研究センター, 教授 (10127904)
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| Co-Investigator(Kenkyū-buntansha) |
MIYCHI Takashi Waseda University, Professor, 教授 (20013401)
TAKANO Masatoshi Waseda University, Associate Professor, 助教授 (00257198)
KOBAYASHI Masanori Waseda University, lecture with tenure, 講師 (70312080)
SHIBATA Toru Aoyama-gakuin University, Department of science and engineering, Professor, 理工学部, 教授 (70082831)
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| Project Period (FY) |
2001 – 2004
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| Keywords | galactic cosmic ray / trans-iron nuclei / isotopic compositeon / mass resolution / large area silicon detector / solid-state track detector / TSUBASA satellite / TIGER balloon experiment |
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| Research Abstract |
The trans-iron cosmic rays were observed by balloon experiments using solid-state track detectors and satellite observation of Ariel-6,HEAO-3 and Trek. The measurement accuracies, however, were unsatisfactory because of low charge resolutions of their detectors. Moreover, these are no observations of trans-iron isotope compositions in cosmic rays. The measurement of these compositions gives crucial constrains on a cosmic ray source and a chemical evolution of the galaxy, including their acceleration and propagation processes.
The basic developments of detectors for trans-iron isotopes and ultra-heavy nuclei up to actinides were performed for future planning of these observations in cosmic rays. Large silicon detectors with high uniformity and the solid-state track detectors such as CR-39 with a high mass resolution of 0.20 amu in rms for iron nuclei were developed in this study. Moreover, in order to establish the analyzing method of cosmic rays, we participated TIGER team of balloon observation. The collision mean-free-paths of Si, Fe and Ni in the atmosphere were obtained with high accuracy with the measurements of energy dependence of those nuclei for total charge-changing cross-sections. Furthermore, the study of high energy phenomena in the solar atmosphere and the interplanetary space is a miniature version occurring in the galaxy and gives an important clue to study dynamical astrophysical processes. In order to understand these phenomena, heavy ions in the radiation belts and from solar particle events were observed using the data from HIT instrument onboard TSUBASA satellite. It is found that the flux ration of helium isotopes, 3He/4He is greatly enhanced in the radiation belt by 3-4 orders of magnitude as compared with the solar abundance ratio. The origin of 3He in radiation belt is still under study.
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