UV responce of semiconductor photo sensor PPD/SiPM

• Project/Area Number: 16K05389
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Particle/Nuclear/Cosmic ray/Astro physics
• Research Institution: High Energy Accelerator Research Organization
• Principal Investigator: Nakamura Isamu 大学共同利用機関法人高エネルギー加速器研究機構, 素粒子原子核研究所, 講師 (70391703)
• Project Period (FY): 2016-04-01 – 2020-03-31
• Project Status: Completed (Fiscal Year 2019)
• Budget Amount: ¥3,770,000 (Direct Cost: ¥2,900,000、Indirect Cost: ¥870,000); Fiscal Year 2018: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000); Fiscal Year 2017: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000); Fiscal Year 2016: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
• Keywords: 光検出器 / 未完 / 技術不足 / 真空紫外 / 半導体光検出器 / 紫外線応答 / 紫外線 / 時間応答

Outline of Final Research Achievements

In photo sensor, UV photon is absorbed near surface where electric field is small. Hence, it is considered that generated carrier reaches to multiplication area through defusion rather than electric field. But this is not experimentally confirmed.
This study is to reveal the detection mechanism by measuring time response, that is different depending on whether defusion of not.
The original plan was to use UV light from liquid argon. But considering its difficulty of handling liquid argon, decided to use gas argon instead of liquid. However, valuable result couldn't be obtained, due mostly to technical difficulty. The idea of this study is still valid and all set up exist, I'd like to continue the study.

Academic Significance and Societal Importance of the Research Achievements

本研究は最近一般的になってきた半導体光検出器PPD/SiPMが紫外線に対してどのような機構で応答しているのかを明らかにするものです。
半導体光検出器を構成するシリコンの紫外線に対する吸収長は非常に短く(ナノメートルレベル)、紫外線に感度のある半導体光検出器は難しいと思われていました。
この研究により、検出器の極表面に近い場所で生成されたキャリアが、増幅領域まで伝播する機構を解明できれば、より高い紫外線対する感度を持つ半導体光検出器が開発できるようになると思われました。