大尺寸伽玛碘化亚铜超快闪烁晶体共溶质溶剂蒸发法生长及其性能调控

The detection of high-energy pulse X-ray (>10 keV) with ultrahigh counting rate plays an important role in laser inertial confinement fusion (ICF) diagnosis. The critical issue is to achieve ultrafast scintillation crystals with large size and excellent performance. Closely surrounding the strategy demands of ICF development in our country and aiming at the current problems of gamma cuprous iodide (CuI) crystals, such as small size and low light yield, a technique of solvent evaporation with cosolute is firstly proposed for growing large gamma CuI ultrafast scintillation crystals, and the corresponding fundamental researches on the growth processing and performance modulation of the crystals will be carried out in this proposal project. . An effective growth technique for large gamma CuI ultrafast scintillation crystals will be established and the optimal processing conditions for the growth of the crystals with excellent scintillation performances will be obtained through comprehensive research with multi-routes, such as crystal growth processing optimiztion, the first-principles simulation, microstructures (e.g. defects and coordination environments, etc.) modulation and artificial photonic crystal design. The mechanism of the effect of the crystal microstructures on the energy transfer process and scintillation properties will be revealed by exploring the intrinsic relationship between the scintillation characteristics and the microstructures. The large gamma CuI scintillation crystals with independent intellectual property rights will be developed through our efforts, so as to satisfy the requirements of high-energy pulse X-ray detection with ultrahigh counting rate in the field of laser ICF.

超高计数率、高能脉冲X射线（>10 keV）探测对于激光惯性约束核聚变（ICF）诊断具有十分重要的作用，其关键在于获得大尺寸、性能优良的超快闪烁晶体。紧扣我国ICF发展的战略需求，针对目前伽玛碘化亚铜（CuI）尺寸小、光产额低等问题，率先提出大尺寸伽玛CuI超快闪烁晶体共溶质溶剂蒸发生长新技术，开展该晶体的生长及其性能调控等基础研究。本项目拟通过晶体生长工艺优化、第一性原理计算、微结构（缺陷、配位环境等）调控，以及人工光子晶体构建等综合研究，建立生长大尺寸伽玛CuI晶体的有效方法，获得制备高闪烁性能晶体的优化工艺条件；探索晶体微结构与其闪烁性能之间的内在关系，揭示它对能量传递过程和闪烁性能影响的作用机理，研制出具有自主知识产权，基本满足ICF对超高计数率、高能脉冲X射线诊断需求的大尺寸伽玛CuI闪烁晶体。

高性能超快闪烁体是实现超高计数率、高能脉冲X射线探测与成像的关键。据此，我们开展了大尺寸γ-CuI超快闪烁晶体生长与性能调控等相关基础研究。结合第一性原理、溶剂蒸发法晶体生长和阴离子掺杂改性等方面研究，成功生长出大尺寸γ-CuI闪烁晶体，同时还研制出闪烁性能优异的CuI:Cl-PS（PS，聚苯乙烯）新型复合闪烁体，达到预期目标，完成了本项目的研究任务。. 采用第一性原理模拟计算，详细研究了阴离子（F、Cl和Br等）掺杂对γ-CuI晶体中铜、碘空位等缺陷形成能的影响，以及缺陷态与闪烁性能的关联。揭示了阴离子掺杂提高γ-CuI晶体近带边超快发光，并抑制其深能级慢发光的机理，即增加铜空位、降低碘空位等缺陷浓度，并从实验上得以验证。该结论为优化γ-CuI晶体闪烁性能提供了指导。. 通过晶体生长方法探索，建立了共溶质溶剂蒸发γ-CuI晶体生长方法。以ZnI2和LiI等为共溶质，生长出边长达到20 mm的大尺寸γ-CuI晶体，并获得了相关优化工艺参数。证实了引入共溶质不仅可提高所生长晶体的尺寸，还能显著改善其闪烁性能。在阴离子掺杂实验研究中，我们发现Cl掺杂改性效果最佳。考虑到铜的阴离子化合物具有强氧化性，通过引入惰性保护气氛，提高晶体生长液稳定性，延长晶体生长周期，生长出闪烁性能优异的γ-CuI:Cl晶体。这些关于晶体生长的经验都具有一定的推广价值。. 项目研究过程中，我们还提出并研制出一种基于γ-CuI材料的γ-CuI:Cl-PS新型复合闪烁体。该新型复合闪烁体性能优异，具有亚纳秒量级超快发光、无深能级慢发光成份、发光稳定性好等优点，在高能脉冲、超高计数率闪烁探测与成像领域具有应用前景。. 总体来说，本项目的研究成果为高能脉冲X射线的超快探测与成像奠定了坚实的基础。