がん治療装置の普及を促進する『量子メス』に必要なイオン数の達成に見通し～レーザー光で加速したイオン速度を整えて個数を10倍増やす！　産業応用にも期待～

2025-09-27 量子科学技術研究開発機構,高エネルギー加速器研究機構,住友重機械工業株式会社,九州大学,山形大学,科学技術振興機構

量子科学技術研究開発機構（QST）、高エネルギー加速器研究機構、住友重機械工業、九州大学、山形大学、JSTの共同研究チームは、重粒子線がん治療装置の小型化を目指す「量子メスプロジェクト」で重要な成果を得ました。レーザー加速で生成したイオンは速度が不ぞろいなため利用が難しいという課題がありましたが、新たに「位相回転空胴」を導入することで、目標速度を持つイオン個数を最大10倍に増加させることに成功。これにより必要数（10⁹個）に到達できる見通しを得ました。さらに、従来の加速器よりも100倍以上高密度のイオン集団を1ナノ秒という極短時間で観測することにも成功しました。本成果はがん治療の普及に加え、原子力材料の耐久試験や材料・生命科学研究にも応用が期待されます。

位相回転空胴によるイオン速度制御の装置概要図

＜関連情報＞

高フラックスレーザー駆動陽子バンチの実証とリアルタイム非破壊診断
Demonstration and real-time non-destructive diagnosis of a high-flux laser-driven proton bunch

Hironao Sakaki;Sadaoki Kojima;Tsuyoshi Suwada;Thanh-Hung Dinh;Hiroshi Tsutui;Yutaka Touchi;Kiyotaka Ohtomo;Haruya Matsumoto;Nobuatsu Aoki;Hikaru Souda;Masayasu Hata;Yoichi Yamamoto;Fuyumi Itou;Masaharu Nishikino;Toshiyuki Shirai;Kiminori Kondo
Review of Scientific Instruments Published:September 26 2025
DOI:https://doi.org/10.1063/5.0274838

To realize a compact and high-intensity ion beam facility based on laser-driven ion acceleration by Target Normal Sheath Acceleration, we constructed a dedicated beamline capable of transporting and controlling proton beams with kinetic energy of 1.5 MeV. The system consists of a quadrupole triplet electromagnet for spatial focusing and an energy-compressing cavity (ECC) for longitudinal phase rotation, enabling momentum compression. A wall current monitor (WCM), installed 4.2 m downstream of the source, enables real-time, non-destructive bunch diagnostics. Using this setup, a single-bunch proton with a kinetic energy of 1.5 MeV was generated from a 5.0 μm-thick nickel tape target and compressed by phase rotation in the ECC. The time-domain standard deviation of the bunch length, as measured by the WCM, was found to be less than 0.14 ns (limited by the measurement resolution), and the bunch was transversely focused to a root-mean-square diameter of ∼10 mm at the WCM position, as determined from beam transport simulations. The single-shot irradiation fluence exceeded 5.5 × 10⁷ (protons/cm²)/bunch with an energy spread of 4.6%, corresponding to a peak flux of ∼10¹⁷ (protons/cm²)/s. Such a low-energy, sub-nanosecond, high-flux single-bunch proton beam is extremely difficult to achieve with conventional ion accelerator systems. It enables experimental investigation of fundamental material damage processes with high temporal resolution, including early stage defect formation and atomic displacements. This laser-driven ions beam study is expected to significantly advance time-resolved applications requiring sub-nanosecond temporal resolution, particularly in the fields of advanced materials research.