激光束模拟剂量率效应关键技术分析

Key techniques of pulse-laser simulation of dose rate effects

剂量率效应是电子元器件和系统的抗辐射鉴定考核中不可缺失的项目。脉冲激光束是一种较好的模拟剂量率效应的手段。相比传统脉冲X射线装置,利用激光束模拟剂量率效应,脉冲输出稳定,寄生电场效应低,可进行器件微区辐照,而且激光束模拟剂量率装置易实现,剂量率试验的时间和成本均远低于高能X射线辐射试验。虽然激光束模拟剂量率装置具有上述优势,但由于激光束本身的特性,这种方法具有一定的局限性,其中高功率激光的非线性吸收、器件金属线的遮挡效应会严重影响激光束模拟剂量率效应的适用性。因此必须通过适当的试验设计和理论修正才能获得相对准确的剂量率试验结果。本文从激光束模拟剂量率效应原理出发,详细阐述影响激光束剂量率模拟试验适用性的因素,并分析克服这些影响因素的途径,以指导激光束模拟剂量率效应装置的开发和应用。

Dose rate effect is a mandatory examination item for devices used in nuclear events. Pulse laser sources are widely used for dose rate effects simulation. Compared with transient high dose rate gamma source, a traditional dose rate effects simulation facility, the pulse laser source shows several advantages, including stable pulse output, low parasitic electrical field, capable to micro-dimensional irradiation and low cost. However, the adequacy of pulse-laser based simulation of the dose rate effects in microcircuits may be corrupted mainly due to some limitations such as laser radiation shadowing by the metallization, the non-linear absorption in a high intensity range etc. The adequacy and accuracy of pulse laser-dose rate effects simulation should be improved through experimental design and theoretical correction. This paper reviews the fundamental of pulse laser simulation for dose rate effects, presents the factors limiting the adequacy and accuracy of simulations and addresses the approaches to overcome corresponding factors.