随着超强激光技术的发展，在实验室中研究极端强场下的物理规律成为可能，基于超强激光的强场物理实验，能够研究电子在极端强场下运动和辐射的基本规律，并为发展高亮度高偏振的新型X/$\gamma$射线源提供物理基础，具有重要的科学意义和应用价值。在强场物理实验中，对短脉宽（fs-ps量级）、高通量（探测器处$\sim$\SI{1e19}{photons/cm^2/s}）X/$\gamma$射线脉冲辐射场精确、丰富的物理信息的诊断是一个关键难点问题，这对探测器技术提出了巨大挑战，目前已有的能量累积式诊断技术尚不能完全满足实验需求。特别是在百keV能段，对于脉冲辐射场能谱和偏振等基本特性的诊断尚无有效方法，新的脉冲辐射场诊断技术亟待发展。 本论文提出将电离径迹探测引入脉冲辐射场诊断，将粒子能量信息与粒子电离径迹提供的位置、形态等多维度特征相结合，探索解决百keV能段脉冲辐射场能谱、偏振诊断难题的新方法。 针对百keV能段脉冲辐射场的光子通量、能量和电离径迹尺度、形态特征，本论文结合理论分析与物理仿真模拟，提出了采用同时具有高能量和位置分辨率的半导体像素探测器探测电离径迹的技术路线。并针对Timepix3混合像素探测器这一具体选型，系统地研究了其像素响应与粒子能量、作用位置的关系，提出了使用宇宙线缪子径迹标定探测器响应非线性的方法，获得了\SI{61.3}{\micro\metre}的三维位置测量精度。同时，针对从十微米量级复杂多维度电离径迹中提取物理特征的难题，发展了将聚类算法和电子径迹算法相结合的数据分析算法，实现了一套识别、筛选单光子电离径迹，并提取多种物理特征的一般性方法。 在此基础上，本论文抓住百keV能段光子与物质作用的主要物理过程-康普顿散射，发展了基于多维度物理特征进行脉冲辐射场能谱重建和偏振测量的新方法。本论文发展的基于康普顿散射电子径迹的能谱诊断方法，在\SI{200}-\SI{550}{keV}能段内可实现优于25\%的能量分辨率，除此方法外尚无方法可以在该能段针对脉冲辐射场给出确切能量分辨率，该能谱诊断方法的可行性也得到了Timepix3原理验证实验的检验。发展的偏振诊断方法可对\SI{100}-\SI{500}{keV}能段内的脉冲辐射场偏振特性进行测量，并具有逐事例选取能量进行偏振测量的能力，该方法的可行性通过康普顿成像实验得到了初步验证。本论文提出的这些方法能较好地满足未来开展强场物理实验的需求，有望在强场物理实验中得到广泛应用。

With the development of high-intensity laser technology, it has become possible to experimentally study the quantum electrodynamics (QED) effects, which dominate the interaction of elementary particles with an intense electromagnetic field. The experimental investigation of these effects would be important for fundamental physics as well as the generation of high-quality $\gamma$-ray beams and their applications. In these experiments, the ultra-short X/$\gamma$-ray (femtosecond to picosecond) pulses with ultra-high flux ($\sim$\SI{1e19}{photons/cm^2/s} at the detector) can be generated, and the diagnostics for these pulses are the basis of these experimental researches. However, the current diagnostics for ultrashort X/$\gamma$-ray pulses, which usually work in the time-integration mode, cannot satisfy the requirement of the strong field QED experiments. Especially in the hundreds of keV bands, there is a lack of diagnostics for the energy spectrum and polarization which are the most important properties of the ultrashort X/$\gamma$-ray pulses. Thus the research and development of new diagnostic methods are of utter importance. To fulfill the requirement of the experiment, diagnostics based on ionization track detection are proposed. Based on the particle energies, interaction positions, and ionization track morphologies which can be derived from the tracker response, solitary tracks from single photons can be identified, and the energy spectrum and polarization could be reconstructed precisely from this extensive information. The high-efficiency detection of ultrashort X/$\gamma$-ray pulses in the hundreds of keV bands and the accurate measurement of the ionization tracks are challenging. Through theoretical analysis and physical simulation, we propose that using the state-of-the-art semiconductor pixel detectors to detect the ionization tracks from ultrashort X/$\gamma$-ray pulses would be efficient. Deriving the physical features from complex and multi-dimensional ionization track images would be difficult. The clustering algorithm and electron track algorithm are used to solve this problem. The semiconductor pixel detector, such as the hybrid pixel detector Timepix3, suffers from the nonlinear response problem. The energy response, the three-dimensional spatial resolution, and the calibration methods of Timepix3 are studied systematically, and the calibration method using cosmic muon tracks is proposed. The nonlinear response of Timepix3 has been well corrected and the three-dimensional spatial resolution is improved. Based on the research of ionization track detection method and the data processing algorithm, a spectrometer based on the detection of Compton electron tracks and a polarimeter based on the detection of Compton scattering events inside the pixel detector are proposed, and the spectrometer and polarimeter can be applied to diagnose the laser-plasma produced X/$\gamma$-ray pulses. The spectrometer has an energy resolution of better than 25\% in the \SI{200}-\SI{550}{keV} energy band, and there is no other spectrometer available with such high accuracy in this energy band for the diagnosis of ultrashort X/$\gamma$-ray pulses. The polarimeter can measure the polarization properties of ultrashort X/$\gamma$-ray pulses effectively in the \SI{100}-\SI{500}{keV} energy band, meanwhile, the polarimeter can measure the energies of single photons. Therefore, the polarimeter can provide extensive information that cannot be obtained before. In this paper, the proof-of-principle experiments of these proposed methods are carried out using Timepix3, and the practical feasibility of these proposed methods is proved. The research proves that these methods can satisfy the requirement of the strong field QED experiments and these methods are expected to be widely used in the future.