Charge-collection efficiency of single-crystal CVD diamond detector for low-energy charged particles with energies ranging from 100 keV to 2 MeV

単結晶CVDダイヤモンドを用いた放射線検出器における100keV2MeVの荷電粒子入射に対する電荷収集効率に関する研究

佐藤 優樹  ; 村上 浩之*; 嶋岡 毅紘*; 坪田 雅功*; 金子 純一* 

Sato, Yuki; Murakami, Hiroyuki*; Shimaoka, Takehiro*; Tsubota, Masakatsu*; Kaneko, Junichi*

The performance of a diamond detector created from a single-crystal diamond grown by chemical vapor deposition was studied for application in detecting charged particles having energies ranging from 100 keV to 2 MeV. Energy peaks of these low-energy ions were clearly observed. However, we observed that the pulse height for individual incident ions decreases with increasing atomic number of the ions. We estimated the charge collection efficiency of the generated charge carriers by the incident charged particles. While charge collection efficiency above 95% is achieved for helium (He) at energies above 1.5 MeV, over the same incident energy range, the efficiencies are lower for heavy-ions: 70% for silicon (Si) and 30% for gold (Au). We also found that the charge collection efficiency decreases as the generated charge density inside the diamond crystal increases.