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The precise measurement of laser-accelerated MeV/n-class high-Z ions and protons using CR-39 detectors
https://repo.qst.go.jp/records/72148
https://repo.qst.go.jp/records/7214807cfb15f-ce33-421c-9da5-3944a17cd953
| Item type | 会議発表用資料 / Presentation(1) | |||||
|---|---|---|---|---|---|---|
| 公開日 | 2017-02-02 | |||||
| タイトル | ||||||
| タイトル | The precise measurement of laser-accelerated MeV/n-class high-Z ions and protons using CR-39 detectors | |||||
| 言語 | ||||||
| 言語 | eng | |||||
| 資源タイプ | ||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_c94f | |||||
| 資源タイプ | conference object | |||||
| アクセス権 | ||||||
| アクセス権 | metadata only access | |||||
| アクセス権URI | http://purl.org/coar/access_right/c_14cb | |||||
| 著者 |
Kanasaki, M.
× Kanasaki, M.× Jinno, S.× Sakaki, Hironao× Kondo, Kiminori× Oda, K.× Yamauchi, T.× Fukuda, Yuuji× 榊 泰直× 近藤 公伯× 福田 祐仁 |
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| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | The precise quantitative characterization of laser-accelerated ion beams in both space and energy domains is a critical issue in understanding the physics of the laser-driven ion acceleration process. To characterize the ion beam, CR-39 detectors have been used for a long time in laser-driven ion acceleration experiments as the most reliable detector. This is because CR-39 detectors have the great advantage of being insensitive to high-energy photons and electrons. In addition, CR-39 detectors are robust against electromagnetic pulses (EMP) from intense laser-plasma interactions, therefore, it would be suitable for the future ion acceleration experiments using multi-PW class lasers. For example, the multi-step etching technique, in which the etching and the microscopic observations are repeated every certain period of the chemical etching time, has been applied to laser-driven ion acceleration experiments to demonstrate a tenfold improvement in the accuracy of determination of the maximum proton energy with uncertainty E = 0.1 MeV. In the present study, to demonstrate the capability of CR-39 for precise measurements in the energy and spatial distributions of laser accelerated ions, CR-39 detectors have been applied to the laser-driven ion acceleration experiment using cluster-gas target, which consists of CO2 clusters embedded in background H2 gas, with the J-KAREN laser (1 J, 40 fs) at QST-KPSI. In order to obtain the high resolution energy spectra of each ion species, the new diagnosis method, which can separately measure the precise energy spectra of the laser-accelerated MeV/n class high-Z ions and that of MeV protons, has been developed. By a careful analysis of etch pit structures using the multi-step etching technique, the maximum energies of carbon/oxygen ions (from clusters) and protons (from background gas) were determined as 1.1±0.1 MeV and 1.6±0.1 MeV/n, respectively. The shapes of energy spectra revealed that the number of carbon/oxygen ions sharply decreased at the maximum energy and that of protons gradually decreased with increasing energy. In addition, in the same experiment series, to obtain the spatial distribution of laser-accelerated ions, CR-39 detectors were installed as to surround the laser focal spot. The CR-39 detectors, which were installed at 45̊ and 90̊ from laser propagation direction, showed a homogeneous etch pit spatial distribution. On the other hand, an inhomogeneous etch pit spatial distribution was observed on CR-39 installed at the laser propagation direction. The inhomogeneous distribution suggests that the spatial distribution of the ion beam could be modulated by the effect of electromagnetic structures created in the laser-plasma. The potential abilities of CR-39 detectors enable us to discuss the laser-driven ion acceleration mechanism based on qualitative information on laser-accelerated ions provided by the analysis of etch pit structures on CR-39 detectors, therefore, CR-39 detectors are the most qualified candidate detector for characterization of the laser accelerated ions. |
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| 会議概要（会議名, 開催地, 会期, 主催者等） | ||||||
| 内容記述タイプ | Other | |||||
| 内容記述 | International Symposium on Ultrafast Intense Laser Science 15 | |||||
| 発表年月日 | ||||||
| 日付 | 2016-10-04 | |||||
| 日付タイプ | Issued | |||||
