Study of the relationship between hierarchic structure of track potential and track structure produced by quantum beams

2023 Fiscal Year Final Research Report

• Project/Area Number: 18K11935
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 80040:Quantum beam science-related
• Research Institution: National Institutes for Quantum Science and Technology
• Principal Investigator: Moribayashi Kengo 国立研究開発法人量子科学技術研究開発機構, 量子生命科学研究所, 上席研究員 (70354975)
• Project Period (FY): 2018-04-01 – 2024-03-31
• Keywords: イオン照射 / 二次電子の運動 / トラックポテンシャル / 熱平衡化 / プラズマ / シミュレーション / クラスターイオン

Outline of Final Research Achievements

In this study, we aimed to elucidate the relationship between the hierarchic structure of track potential (which is space distribution of energy deposition) and track structure (which is the electric field) and the production processes of plasma irradiated by quantum beams. This study is expected to clarify the reason why heavy ion has high biological effect in cancer therapy.
We treated irradiation of heavy ions and cluster ions. To elucidate the relationship and the production processes mentioned before, we studied (i)probabilities of secondary electrons escaping the track potential, (ii)thermalization of secondary electrons, and (iii)radial dose, which is the dose in the local reaction as a function of the distance from the incident ion path, through simulations, where a secondary electron is the electron produced by ionization due to incident ion impact.

Free Research Field

量子ビーム、原子分子物理、プラズマ物理

Academic Significance and Societal Importance of the Research Achievements

世界で初めて重イオン及びクラスターイオン照射で生じる二次電子がトラックポテンシャルに捕獲されるシミュレーションモデルを開発し、二次電子の熱平衡化、及びプラズマを生成過程をシミュレートすることに成功した。このプラズマが生成することは、理論的には、予測されており、理論で求めたプラズマがもたらす生物効果は重粒子線癌治療の治療計画に導入されているが、不明な点も多かった。この研究でこの生成過程等を詳細に解明した。