Strong enhancement of electromagnetic shower development induced by high-energy photons in a thick oriented tungsten crystal

We have observed a significant enhancement in the energy deposition by 25-100 GeV photons in a 1 cm thick tungsten crystal oriented along its <111> lattice axes (data of Fig. 2). At 100 GeV, this enhancement, with respect to the value observed without axial alignment, is more than twofold. This effect, together with the measured huge increase in secondary particle generation (data of Fig. 3) is ascribed to the acceleration of the electromagnetic shower development by the strong axial electric field. The experimental results have been critically compared with a newly developed Monte Carlo adapted for use with crystals of multi-X_0 thickness (data of Fig.2, 3 and 4). These results may prove to be of significant interest for the development of high-performance photon absorbers and highly compact electromagnetic calorimeters and beam dumps for use at the energy and intensity frontiers.

我们观测到，当厚度为1 cm的钨晶体沿其<111>晶格轴取向时，25~100 GeV光子的能量沉积出现显著提升（对应图2数据）。在100 GeV能区，相较于未进行轴向取向的对照条件，该能量沉积的提升幅度超过两倍。该效应与实测得到的次级粒子产额大幅提升现象（对应图3数据），均可归因于强轴向电场对电磁簇射发展的加速作用。本实验结果与新开发的、适用于多辐射长度（X₀）厚度晶体的蒙特卡洛（Monte Carlo）模拟结果进行了严谨比对（对应图2、3及4数据）。上述研究结果，可为面向能量前沿与强度前沿的高性能光子吸收体、超高紧凑型电磁量能器及束流收集器的研发提供重要参考。