High-Energy Laser-Proton Acceleration from Cryogenic Hydrogen

拟议中的研究将应用高功率激光照射微观冰层，并将粒子加速到高速。目标是展示迄今为止已知的最高加速效率，并提供适合应用的粒子束。与x射线类似，高速粒子穿透组织，但只在人体深处的一个点上储存大部分能量。因此，它们非常适合摧毁癌细胞。激光驱动的粒子束有望具有所需的特性，从而可以进一步开发用于肿瘤治疗。它们紧凑的附加优势将使它们广泛用于医院和研究中心。如果成功，该项目将为社会带来很高的回报。该奖项将为斯坦福大学的一名研究生提供全职支持，为一名博士后提供兼职支持，这与该项目为加速器科学领域培养急需的劳动力的目标保持一致。该研究项目将通过高强度短脉冲激光与低温氢的相互作用产生纯高能质子束。这些实验利用了斯坦福大学最近开发的一种新型连续流动的低温微射流。因此，该项目处于独特的位置，可以同时实现该领域迄今为止难以实现的对能量、电荷、纯度、光束发射度和重复率的所有要求。现有的粒子池模拟表明，在与激光的相互作用过程中，液态氢会变得透明，从而增强了片电场，并产生能量大于50兆电子伏特的近单能量质子束。通过实验证明所预测的质子束将是一项非常重要的成就，也是一种新的加速器物理的证明。此外，这些光束将适合注射，并将因此激发对混合加速器的新研究，这些加速器具有巨大的潜力，可以提供迫切需要的230 MeV及以上的能量，用于质子放射照相、成像和肿瘤治疗。

The proposed research will apply high-power lasers to irradiate a microscopic ice layer and accelerate particles to high speeds. The goal is to demonstrate the highest acceleration efficiency known to date and to deliver particle beams suitable for applications. Similar to x-rays, particles of high speed penetrate through tissue but deposit most of their energy only at one point deep inside the human body. Thus, they are extremely well suited to destroy cancer cells. The laser-driven particle beams are expected to have the required properties so that they can be further developed for tumor therapies. The added advantage that they are compact will make them widely available for hospitals and research centers. If successful, the project will have high pay-off for society. The award will provide full-time support for a graduate student and part-time support for a postdoctoral associate at Stanford University, in keeping with the goals of the program toward preparation of a much-needed workforce in accelerator science. This research project will produce pure high-energy proton beams from the interaction of a high-intensity short-pulse laser with cryogenic hydrogen. These experiments utilize a novel continuously flowing cryogenic micro-jet that was recently developed at Stanford. Thus, the project is in the unique position to achieve simultaneously all the requirements on energy, charge, purity, beam emittance and repetition rate that up to now have been elusive in this field. Existing particle-in-cell simulations show that liquid hydrogen will become transparent during the interaction with the laser thus enhancing the sheet electric fields and resulting in nearly mono-energetic proton beams of energies larger than 50 MeV. Experimentally demonstrating the predicted proton beams will be a very important achievement, and a demonstration of new accelerator physics. Furthermore, these beams will be suitable for injection and will consequently motivate new studies of hybrid accelerators that have tremendous potential to deliver the urgently needed 230 MeV and above regime for applications in proton radiography, imaging and tumor therapies.