Laser plasma accelerators (LPAs) enable the generation of intense and short proton bunches on a micrometre scale, thus offering new experimental capabilities to research fields such as ultra-high dose rate radiobiology or material analysis. Being spectrally broadband, laser-accelerated proton bunches allow for tailored volumetric dose deposition in a sample via single bunches to excite or probe specific sample properties. The rising number of such experiments indicates a need for diagnostics providing spatially resolved characterization of dose distributions with volumes of approximately 1 cm ${}^3$ for single proton bunches to allow for fast online feedback. Here we present the scintillator-based miniSCIDOM detector for online single-bunch tomographic reconstruction of dose distributions in volumes of up to approximately 1 cm ${}^3$ . The detector achieves a spatial resolution below 500 $\unicode{x3bc}$ m and a sensitivity of 100 mGy. The detector performance is tested at a proton therapy cyclotron and an LPA proton source. The experiments’ primary focus is the characterization of the scintillator’s ionization quenching behaviour.

超强激光加速产生的高能质子束源在基础物理研究、材料科学、生物医疗等领域具有广泛应用前景。基于激光聚变研究中心的SILEX-II装置，开展了高对比度飞秒激光驱动纳米刷靶质子加速实验研究。采用等离子体镜技术进一步提升激光对比度，有效降低了预脉冲对纳米刷靶结构的影响。相比于平面靶，采用纳米刷靶质子截止能量提高到1.5倍，质子束产额增加近一个量级，成功验证了超高功率密度下纳米刷靶对激光离子加速的增强效果，并且有效提升了质子束空间分布的均匀性。研究结果为高品质质子束源的产生和应用提供了技术途径。

中国散裂中子源（CSNS）靶站质子束窗位于环到靶站输运线（RTBT）与靶站交接面，起到隔离加速器高真空和靶站氦气环境的作用。随着束流功率提高，目前质子束窗单层膜结构形式已无法满足CSNS-II 500 kW的高功率需求，因此开展CSNS-II质子束窗研制，设计出双层膜中间通水的冷却结构，完成质子束窗双层膜的薄膜半径、薄膜厚度、水冷槽长度与宽度、对流换热系数等各参数对质子束窗温升与热应力的影响分析。通过冷却水需求分析得出，冷却水流速需大于15 L/min。通过质子束窗主体的流固耦合分析，消除箱体内部死水区域。最终优化后质子束窗薄膜位置最高温度47.8 ℃，薄膜位置最高热应力30.758 MPa。通过FLUKA软件对质子束窗材料的辐照损伤性能进行分析，在每年5000 h工作时长、500 kW高功率束流的辐照下，辐照损伤DPA计算值为1.285 DPA，质子束窗的安全使用寿命在7年以上。

为了系统研究FLASH效应的放射生物学机制，需要一个可以进行超高剂量率细胞辐照实验的平台，该实验平台应具有稳定、大小合适且大范围可调的剂量和平均剂量率。基于国产7 MeV医用质子直线注入器，使用蒙特卡罗程序FLUKA设计并优化了一个单散射照射头。该照射头的材料为40 μm厚度的钽箔，它既充当真空窗又充当散射体，源皮距为26 cm。经过模拟验证，该平台可提供直径为2 cm的照射野，剂量均匀度为4.9%。通过调整单质子脉冲的流强（0.1~1 mA）和脉宽（20~200 μs），该实验平台的平均剂量和平均剂量率可以在6~667 Gy和3.3×10⁵~3.3×10⁶ Gy·s^-1之间调节。基于此，设计了使用单脉冲穿透模式辐照单层细胞的实验，剂量率为3.3×10⁵ Gy·s^-1，剂量在7~40 Gy范围内变化。该实验平台可以探究细胞FLASH效应的总剂量依赖关系，为揭示FLASH效应的机制提供支持。

综合考虑地磁场、高能质子的相对论效应以及同步辐射的影响，建立了质子在空间传输的单粒子运动模型。基于该模型，提出利用贝叶斯优化方法，实现给定质子能量下，质子从空间初始点传输到目标点的精确控制方法，获得了出射方向随出射位置的变化规律，当位置径向角取0°和180°时，位置轴向角的取值不会改变粒子的最优出射方向。研究结果为质子束在空间环境中的长程传输提供理论支撑。

Laser–plasma accelerated (LPA) proton bunches are now applied for research fields ranging from ultra-high-dose-rate radiobiology to material science. Yet, the capabilities to characterize the spectrally and angularly broad LPA bunches lag behind the rapidly evolving applications. The OCTOPOD translates the angularly resolved spectral characterization of LPA proton bunches into the spatially resolved detection of the volumetric dose distribution deposited in a liquid scintillator. Up to 24 multi-pinhole arrays record projections of the scintillation light distribution and allow for tomographic reconstruction of the volumetric dose deposition pattern, from which proton spectra may be retrieved. Applying the OCTOPOD at a cyclotron, we show the reliable retrieval of various spatial dose deposition patterns and detector sensitivity over a broad dose range. Moreover, the OCTOPOD was installed at an LPA proton source, providing real-time data on proton acceleration performance and attesting the system optimal performance in the harsh laser–plasma environment.