Realization of a time-resolved nuclear emulsion detector using a multi-stage shifter and its application to cosmic gamma-ray observation

2023 Fiscal Year Final Research Report

• Project/Area Number: 21H04472
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Medium-sized Section 15:Particle-, nuclear-, astro-physics, and related fields
• Research Institution: Kobe University
• Principal Investigator: Takahashi Satoru 神戸大学, 人間発達環境学研究科, 特命助教 (40402432)
• Co-Investigator(Kenkyū-buntansha): 中野 敏行 名古屋大学, 理学研究科, 准教授 (50345849) ; 青木 茂樹 神戸大学, 人間発達環境学研究科, 教授 (80211689)
• Project Period (FY): 2021-04-05 – 2024-03-31
• Keywords: ガンマ線天文学 / マルチメッセンジャー天文学 / 気球実験 / 原子核乾板 / 多段シフター / タイムスタンプ

Outline of Final Research Achievements

The emulsion film has excellent spatial resolution and can capture extremely precise traces of high-energy gamma rays. Combined with a time-assignment mechanism called a “multi-stage shifter” (consisting of multiple emulsion films, each stage of which is moved at a specific period), this telescope can become an excellent gamma-ray telescope. In order to expand the aperture area and observation time, the key is to make the multi-stage shifter significantly lighter and longer. We reviewed the driving mechanism of conventional multi-stage shifters and devised a roller-driven multi-stage shifter that can realize a large aperture area and long observation time. Finally, a total of four flight models with a total aperture area of 5 m^2 were realized. In 2023, the first practical application of a roller-driven multistage shifter was achieved through a balloon experiment.

Free Research Field

素粒子宇宙物理学

Academic Significance and Societal Importance of the Research Achievements

ガンマ線天文学は宇宙線物理学、高エネルギー天体物理学、宇宙論、基礎物理学と多岐にわたる波及効果をもたらす。また近年では、宇宙高エネルギーニュートリノや重力波の観測が実現しており、多波長・多粒子でのマルチメッセンジャー天文学の新たな時代が幕開けとなる中で、ガンマ線は決定的に重要なメッセンジャーを担っており、その観測の重要性はますます高まっている。エマルションガンマ線望遠鏡による長時間気球飛翔を繰り返すことで「世界最高角度分解能」「世界初偏光有感」「世界最大口径面積」での宇宙高エネルギーガンマ線精密観測実現を目指す。その先駆けとなる気球実験を達成し、科学観測を開始した。