Characteristic dimensions and evolution times of regions of secondary electronic excitations created by the interaction of ionizing radiation with matter cannot be measured directly. At the same time these are essential parameters both for engineering of nanostructured composite materials defining optimal layer thickness and nanoparticles radii and for the development of optimized scintillators. The paper demonstrates how such spatial and temporal data can be extracted from luminescence decay kinetics excited by vacuum ultraviolet (VUV) and X-ray photons at modern sources of synchrotron radiation MAX IV and PETRA III. Specific features of energy-band structure of self-activated crystal CeF3 are discussed, and its potential for a super-fast detection of ionizing radiation evaluated. Diffusion-controlled dipole–dipole interaction of Frenkel excitons is demonstrated to account well for the luminescence non-exponential decay kinetics providing information on the scales of excited regions created by photons of different energy. For 20 eV photons the radius of excited regions is estimated to be 10 nm, and for 200 eV photons it increases to 18 nm. Effective radius of excited regions of complicated shape created by 19 keV is as large as 80 nm and the diffusion length of Frenkel excitons over radiative time is 14 nm.

中文翻译：

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真空紫外和X射线同步辐射下CeF3的衰变动力学

由电离辐射与物质相互作用产生的二次电子激发区域的特征尺寸和演化时间无法直接测量。同时，对于定义最佳层厚度和纳米粒子半径的纳米结构复合材料的工程设计以及优化闪烁体的开发而言，这些都是必不可少的参数。该论文展示了如何从现代同步辐射源 MAX IV 和 PETRA III 处的真空紫外 (VUV) 和 X 射线光子激发的发光衰减动力学中提取此类空间和时间数据。讨论了自激活晶体 CeF3 能带结构的具体特征，并评估了其超快速检测电离辐射的潜力。弗伦克尔激子的扩散控制偶极-偶极相互作用被证明可以很好地解释发光非指数衰减动力学，提供有关由不同能量光子产生的激发区域尺度的信息。对于 20 eV 光子，激发区域的半径估计为 10 nm，而对于 200 eV 光子，它增加到 18 nm。由 19 keV 产生的复杂形状激发区的有效半径高达 80 nm，Frenkel 激子在辐射时间内的扩散长度为 14 nm。