Speaker
Description
A diamond radiation detector based on a diamond semiconductor has been developed as part of a 3U CubeSat project aiming to measure charged particles (≥ 10 keV) escaping from the Earth’s atmosphere along geomagnetic fields. Diamond is known as an excellent material for semiconductor devices because of a bandgap of 5.5 eV and a carrier mobility of 4000 cm2/Vs at RT. Additionally, diamond is expected to have high radiation tolerance. To evaluate the radiation tolerance of our diamond radiation, we conducted proton irradiation tests in The Wakasa Wan Energy Research Center with a total fluence of 8.89 × 109 protons/cm2, equivalent to 10 years of exposure in a sun synchronous polar orbit at 600 km altitude. The detector used in these tests is a single-crystal chemical vapor deposition diamond produced by Element Six Corporation, with a size of 2.0 × 2.0 × 0.5 mm3. We evaluated the detector’s spectroscopic performance by measuring linearity and energy resolution using characteristic X-rays from radioisotope sources of $^{241}\mathrm{Am}$, $^{133}\mathrm{Ba}$, and $^{109}\mathrm{Cd}$. We found that the energy resolution and linearity do not degrade within ranges of 11.2 % and 1.2 %, respectively. These results indicate that the diamond detector has high radiation tolerance, making it suitable for space use.
