| Budget Amount *help |
¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000)
Fiscal Year 2019: ¥390,000 (Direct Cost: ¥300,000、Indirect Cost: ¥90,000)
Fiscal Year 2018: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2017: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
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| Outline of Annual Research Achievements |
Primary knock-on atoms (PKAs) play a fundamental role in radiation damage assessment for proton accelerators, and can also be used to validate physics models for simulating proton-induced nuclear reactions. This study was aim to develop a new measurement system, and by which to provide new experimental data of PKAs.
PKAs created by high-energy proton bombardment consist of nuclides with a continuous mass range from 1 amu to the target nuclide mass, and with an energy spectrum from sub-MeV to several tens of MeV. The new measurement system we proposed in this study consists of two ultrafast timing detectors for time of flight (tof) measurement and a customized dE-E gas ionization chamber. The PKA isotopes are identified by combining the dE-E and tof-E relations, and then their energies can be determined by tof.
The customized dE-E gas ionization chamber along with its gas flow system has been successfully built for this study. It was successfully tested at the Tandem Accelerator of Japan Atomic Energy Agency by using a calibration Am-241 alpha source. The detector performance was also confirmed with a 70-MeV proton beam bombarding a thin carbon target at CYRIC, Tohoku University, and the PKA elements were able to be identified for C, B, Be, and Li.
The ultrafast timing detectors which include an ultrathin carbon foil, an electrostatic mirror, and a microchannel plate detector, were also built. However, the signals of the ultrafast timing detectors were noisy such that true events cannot be separated from background events, which has to be solved befor taking steps forward.
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