| 研究課題/領域番号 |
23K17040
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| 研究機関 | 国立研究開発法人量子科学技術研究開発機構 |
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研究代表者 |
HU JUN 国立研究開発法人量子科学技術研究開発機構, 放射線医学研究所 計測・線量評価部, 研究員 (40912712)
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| 研究期間 (年度) |
2023-04-01 – 2026-03-31
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| キーワード | ATRA / heavy ion / FNTD |
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| 研究実績の概要 |
Given the increasing crewed space exploration, this study aims to develop a new space radiation dosimetry protocol without chemical treatment using only a tiny chip to replace the conventional dosimeters.
We conducted the alpha irradiation experiment this fiscal year using an Am-241 source and He, C and Fe irradiation experiments to make track samples. Based on the track samples, we developed an automatic 3D track reanalysis algorithm consisting of three stages: pre-processing, track localization, and track linking. We successfully detected the tracks with reliable track detection rates. To further analyze the heavy ion tracks, a general fluorescence intensity analysis was performed to evaluate and optimize the measurement conditions for heavy ions.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
We have successfully developed the automatic 3D track reanalysis algorithm (ATRA) and applied it to alpha tracks and heavy ion track detection with a reliable track detection rate. The application of ATRA remarkably increases the track reading and analysis efficiency and decreases the processing period. Based on detecting the track features of heavy ions, we have generally understood the characteristics of heavy ions in the FNTD crystal, especially the fluorescence intensity, track size with perpendicular incident angle, their variation with incident energy, and depth in crystal. There is considerable fluctuation in the fluorescence intensity due to color center concentration between individual detectors. More corrections are needed in future work.
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| 今後の研究の推進方策 |
The alumina-based detectors are subjected to considerable fluctuation in the fluorescence intensity due to color center concentration between individual detectors, which directly influences the linear energy transfer estimation. Moreover, the fluorescence intensity decreases with the depth inside the crystal due to the optical absorption and spherical aberration of the focused laser beam in the FNTD crystal. We will develop a coloration-dependent correction method to normalize the fluorescence intensity to determine the LET. More heavy ion track samples will be prepared to calibrate the FNTDs with LET spectra to apply the FNTD as a space radiation dosimeter.
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| 次年度使用額が生じた理由 |
The FNTD chips of single Al2O3:C,Mg crystals are the primary detecting material in this research. The FNTDs used in this research, produced by Landauer, USA, were out of stock this fiscal year. We will order the new detector chips in the new fiscal year.
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