Development of a brand-new radiation-detection technique by non-linear electrooptics to monitor high-power beam

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K20926
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 15:Particle-, nuclear-, astro-physics, and related fields
• Research Institution: High Energy Accelerator Research Organization
• Principal Investigator: Nishiguchi Hajime 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, 准教授 (10534810)
• Project Period (FY): 2020-07-30 – 2024-03-31
• Keywords: 放射線検出器 / 大強度加速器 / 大強度ビーム / ビームモニタ / 電気光学効果 / 非線形電気光学効果

Outline of Final Research Achievements

In this study, we aim to overcome the problem of radiation damage to beam detectors in high-intensity beams by developing a detector based on a completely different operating principle from conventional detectors. Therefore, we aim to detect electric field disturbances caused by the space charge effect of high-intensity beams by applying the nonlinear electro-optic effect of dielectrics, and to realize a beam monitor with excellent radiation resistance.
We therefore made a refractive index sensor that combines a dielectric that shows a nonlinear electro-optic effect with a laser, and tested it in the laboratory before beam-irradiation test. As a result, we were able to detect changes in the refractive index due to changes in the electric field, but it was found that the time characteristics did not meet the requirements for operation as a beam monitor. It is hoped that this issue will be resolved in the future.

Free Research Field

素粒子物理学

Academic Significance and Societal Importance of the Research Achievements

本研究により、非線形電気光学効果（カー効果）を発現する誘電体による微小な屈折率変化を、レーザーにより光強度を上げることで検知することが出来る可能性を示すことが出来た。残念ながら、大強度ビームモニタとして活用するという本研究の最終目的を達成するには至らなかったが、光産業分野で盛んに利活用されている電気光学効果を、全くの異分野で応用する可能性が見出されたことは大きな意義がある。また、大強度ビームモニタは、高線量被曝量の推定に欠かせない技術であり、今後社会的に課題になることが明らかである、原子炉の廃炉技術開発にも繋がる可能性がある。