利用激光等离子体加速的相对论电子束与高Z靶相互作用，通过韧致辐射获得高能量γ射线来诱发光核反应的方式称为激光驱动光核反应，该研究在核废料嬗变处理、核共振荧光、核医学等领域具有巨大的应用前景。由于造价昂贵、维护成本高，激光器数量与机时有限，目前激光驱动光核反应的研究主要集中在理论计算和实验模拟上。根据理论和模拟结果，实验中光核反应的产额强烈依赖激光和等离子体相互作用产生的电子束和γ射线的品质。为有效提高光核反应的产额，需要通过实验研究探索不同靶束条件下电子束和γ射线的关键参数，尽可能获得高能量、高通量的电子束和γ射线。自1985年啁啾脉冲放大（CPA）技术出现并应用以来，激光功率实现了飞跃式提升，目前激光脉冲的聚焦强度可以达到10²² W/cm²，这使得在实验室条件下开展激光核物理、核天体物理等实验研究成为可能。本文分别利用百TW和PW激光器与不同的靶材相互作用，研究不同实验条件下的激光驱动光核反应，为测量光核反应截面与光核嬗变处理核废料提供了新的方法。

本研究依托北京大学激光等离子体加速器实验室的200 TW激光器和中国工程物理研究院激光聚变中心的SILEX-Ⅱ激光装置，系统的研究了百TW激光与固体薄膜靶、PW激光与高密度气室靶和百TW激光与气体靶三种实验条件下，激光驱动电子加速、γ射线的产生以及光核反应产额，测量了电子束与γ射线的关键参数和Au/Sn光核反应的产额，同时对IP板、电子谱仪和γ堆栈谱仪等关键诊断设备进行了特性研究。具体内容如下：

1.百TW激光与固体薄膜靶相互作用实验中，测量了电子能谱与光核反应产额。结果表明百TW激光与固体薄膜靶相互作用所产生的电子温度最高在8.76 MeV左右，受电子温度的限制，高能量γ射线的产额较低，且大部分γ光子的能量小于靶核的中子分离能，而且活化靶放置位置与打靶点距离较远，因而通过轫致辐射产生的高能γ射线数量不足以满足离线测量法对活化产物的产额要求，因此实验中并未直接测量到光核反应产物的特征信号。

2.SILEX-Ⅱ-PW激光与高密度气室靶相互作用实验中利用电子磁谱仪、电子堆栈谱仪测量了超热电子的能谱与角分布，使用γ堆栈谱仪分析了轫致辐射γ能谱的低能成分谱(10 MeV以下)，利用高产额γ射线诱发¹⁹⁷Au(γ,n)¹⁹⁶Au光核反应，使用离线测量法计算了¹⁹⁶Au的产额，同时利用Bubble探测器监测了瞬发中子的角分布以及产额，为后续在PW激光器上进一步探索利用激光驱动的γ射线测量光核反应的截面的工作提供了数据与技术支撑。

3.百TW激光与气体靶相互作用的实验中，对尾场加速产生的电子能量、指向性、发散角、电荷量等关键指标进行了研究，结果显示通过尾场加速可以稳定的产生近单能、小发散角、高指向性的百 pC高能电子束，使用实验测量结合GEANT 4模拟的方法计算了电子束经过2 mm钽靶后的高于8 MeV的γ射线的产额，进一步利用离线测量法测量此条件下诱发Sn(γ,x)反应产额。Sn的一种核素¹²⁶Sn为反应堆长寿命裂变产物，一般实验上使用相同元素的稳定核素来替代长寿命裂变产物做可行性实验，因此该路线有望成为核废料处理的一种补充方法。

4.由于IP板不受电磁场的影响，对强激光打靶实验中产生的电磁脉冲不敏感，常作为探测介质广泛应用于激光驱动的辐射粒子探测诊断设备中。本文对IP板的特性参数进行实验刻度，同时利用光激励发光机理模型阐述了IP板表现的特性参数，为今后进一步深入研究IP板的工作机理以及过饱和条件下的数据外推提供了理论模型和数据基础。自行设计制作了以IP板作为探测介质的紧凑型电子磁谱仪及γ射线堆栈谱仪，可用于激光实验中电子束与γ射线能谱的测量，通过理论计算与实验刻度相结合的方法对电子谱仪和γ谱仪的特性进行了研究，证实了其在激光等离子实验中的适用性。此外卢瑟福背散射(RBS)法常用于不破坏样品的同时精确测量薄膜的厚度，可用于对核反应实验蒸镀的薄膜靶厚度进行精确测量。使用RBS法测量靶厚与称重法相比，将靶厚的测量误差从10%降低到7%以内，可有效减小光核反应相关结果的误差。

综上所述，本文开展了激光驱动Au/Sn光核反应的实验研究，以及激光与物质相互作用中的电子束与γ射线诊断技术研究，最终获得了一定的数据积累和技术经验，可以为后续在PW/百TW激光器上开展核嬗变以及光核反应截面测量等研究工作提供数据参考与技术支持。

Laser-driven photonuclear reactions, achieved through interactions between relativistic electron beams accelerated by laser plasma and high-Z targets, which produce high-energy gamma rays via bremsstrahlung radiation, hold significant potential in fields such as nuclear waste transmutation, nuclear resonance fluorescence, and nuclear medicine. Due to the high cost and maintenance requirements of lasers, coupled with limited availability of laser systems and operational time, research on laser-driven photonuclear reactions currently focuses predominantly on theoretical calculations and experimental simulations. According to theoretical and simulation outcomes, the yield of photonuclear reactions in experiments strongly depends on the quality of electron beams and gamma rays produced by the interaction between the laser and plasma. To effectively enhance the yield of photonuclear reactions, it is essential to explore, through experimental research, the critical parameters of electron beams and gamma rays under various target conditions, aiming to achieve high-energy and high-flux beams and gamma rays. Since the introduction and application of Chirped Pulse Amplification (CPA) technology in 1985, there has been a dramatic increase in laser power, with current laser pulses capable of achieving focused intensities up to 10²² W/cm². This advancement has made it feasible to conduct experimental research in fields such as laser nuclear physics and nuclear astrophysics under laboratory conditions. This paper utilizes both hundred TW and PW lasers interacting with various target materials to investigate laser-driven photonuclear reactions under different experimental conditions. This research provides new methods for measuring photonuclear reaction cross-sections and for the photonuclear transmutation processing of nuclear waste.

This study, conducted at the Peking University Laser Plasma Accelerator Laboratory with a 200 TW laser and the SILEX-II laser facility at the Institute of Laser Fusion, Chinese Academy of Engineering Physics, systematically investigated laser-driven electron acceleration, gamma-ray production, and photonuclear reaction yields under three experimental conditions: interaction of a hundred TW laser with solid thin-film targets, a PW laser with high-density gas chamber targets, and a hundred TW laser with gas targets. The research measured critical parameters of electron beams and gamma rays, as well as the yields of Au/Sn photonuclear reactions. Additionally, the study examined the characteristics of key diagnostic devices, including Image Plates (IP), electron spectrometers, and gamma-ray stack spectrometers. The specific contents are as follows:

1. In the experiment involving the interaction between a hundreds TW laser and solid thin-film targets, the electron energy spectrum and photonuclear reaction yields were measured. The results indicated that the maximum electron temperature produced by the interaction between the hundred TW laser and solid thin-film targets was approximately 8.76 MeV. Due to the limitations imposed by the electron temperature, the yield of high-energy gamma rays was low, and the energy of most gamma photons was below the neutron separation energy of the target nuclei. Additionally, the activation target was placed at a considerable distance from the point of impact, resulting in a quantity of high-energy gamma rays produced through bremsstrahlung radiation that was insufficient to meet the yield requirements for offline measurement methods of the activated products. Therefore, characteristic gamma-rays of photonuclear reaction products were not directly measured in the experiment.

2. In the experiment involving the SILEX-II PW laser and high-density gas chamber targets, the energy spectrum and angular distribution of superthermal electrons were measured using an electron magnetic spectrometer and an electron stack spectrometer. The low-energy component of the bremsstrahlung gamma-ray spectrum (below 10 MeV) was analyzed using a gamma stack spectrometer. High-yield gamma rays were used to induce the ¹⁹⁷Au(γ,n)¹⁹⁶Au photonuclear reaction, and the yield of ¹⁹⁶Au was calculated using an offline measurement method. Additionally, a Bubble detector was used to monitor the angular distribution and yield of prompt neutrons. This provided data and technical support for further exploration of using laser-driven gamma rays to measure photonuclear reaction cross-sections on PW lasers in subsequent experiments.

3.In the experiment involving the interaction of a hundreds TW laser with a gas target, key metrics such as the energy, directivity, divergence angle, and charge of electrons produced by wakefield acceleration were studied. The results indicated that wakefield acceleration could stably produce high-energy electron beams with near-monoenergetic properties, low divergence angles, and high directivity, with charges in the hundreds of picoCoulombs. The yield of gamma rays above 8 MeV, after the electron beam passed through a 2 mm thick tantalum target, was calculated using a combination of experimental measurements and GEANT4 simulations. Furthermore, the yield of the Sn(γ, x) reaction induced under these conditions was measured using an activation method. The isotope ¹²⁶Sn of Sn is a long-living fission product in nuclear reactors. In general, stable isotopes of the same element are used in experiment as substitutes for long-lived fission products to conduct feasibility studies. Therefore, this approach holds promise as a supplementary method for nuclear waste management.

4. Because Image Plate (IP) is unaffected by electromagnetic fields, they are insensitive to the electromagnetic pulses produced in high-intensity laser-target experiments. As a result, they are commonly used as the detection medium in diagnostic devices for detecting radiation particles driven by lasers. This paper conducts experimental calibration of the characteristics of IP. Additionally, the characteristics of IP explained through a model of photostimulated luminescence. This provides a theoretical model and foundational data for future in-depth research into the working mechanisms of Image Plates and data extrapolation under supersaturation. A compact electron magnetic spectrometer and gamma-ray stack spectrometer were independently designed and manufactured, utilizing Image Plates (IP) as the detection medium.

These can be used for measuring the energy spectra of electron beams and gamma rays in laser experiments. The characteristics of the electron spectrometer and gamma spectrometer were studied using a combination of theoretical calculations and experimental calibration. This confirmed their applicability in laser plasma experiments. Rutherford Backscattering Spectrometry (RBS) is commonly employed for non-destructive and precise measurement of thin film thickness. It can be employed for precise measurement of the thickness of vapor-deposited films used in nuclear reaction experiments. Compared to the weighing method, RBS for measuring target thickness, reducing the measurement error of target thickness from 10% to within 7% can effectively decrease errors in photo-nuclear reaction-related results.

this paper presents experimental research on laser-driven Au/Sn photo-nuclear reactions and research on diagnostic techniques involving electron beams and gamma rays in laser-matter interaction. The accumulated data and technical experience obtained ultimately can provide valuable data references and technical support for subsequent research endeavors, such as nuclear transmutation and photo-nuclear reaction cross-section measurements, conducted on PW/100 TW laser systems.