Comprehensive Understanding of Galactic and Extragalactic Cosmic-ray Acceleration by Exploring Gamma-ray Observations beyond 100 TeV

2023 Fiscal Year Final Research Report

• Project/Area Number: 20H01916
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 15020:Experimental studies related to particle-, nuclear-, cosmic ray and astro-physics
• Research Institution: Nagoya University
• Principal Investigator: Okumura Akira 名古屋大学, 宇宙地球環境研究所, 講師 (90645011)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 宇宙線物理学 / ガンマ線天文学 / チェレンコフ望遠鏡アレイ（CTA） / 半導体光検出器

Outline of Final Research Achievements

In this research, our objective was to develop the focal-plane camera for the Small-Sized Telescopes of the Cherenkov Telescope Array, the next-generation gamma-ray observatory, and to establish an observational method to search for Galactic cosmic-ray accelerators capable of elevating the cosmic-ray energies to the PeV energy band. Because of the difficulty in international collaboration after COVID-19 and delays in the CTA project, we were unable to finish test observations of gamma-ray sources using our first Cherenkov camera. However, we have nearly finalized the design of the camera intended for mass production, which includes up to 70 units. Nagoya University played a key role in the performance evaluation of silicon photomultipliers and the optical simulation of the telescope optical system. The results of this work were presented at international conferences.

Free Research Field

宇宙線物理学

Academic Significance and Societal Importance of the Research Achievements

本研究では紫外線を観測可能な新型の半導体光検出器と、その出力を高速に読み出す専用の波形記録回路を組み合わせることにより、宇宙ガンマ線が地球大気中で生じる大気チェレンコフ光を1ナノ秒ごとに連続撮影する超高速カメラを開発した。これにより半導体技術や集積回路技術を前進させるだけでなく、ガンマ線観測や周辺領域での同様の技術の転用が可能になった。将来的にはこの技術で銀河系内宇宙線加速天体の発見が見込まれる。