Failure Analysis of Beam Scanning system of High-power DC Industrial Electron Accelerator

Abstract

Reliable performance of high-power electron accelerators is a very important aspect, as the numerous industrial applications for which they are employed require 24 x 7 operation. For this purpose, it is necessary to understand the failures that occur in such accelerator systems and employ mitigation methods to ensure their availability. Beam scanning system, which helps to deliver a uniform dose to the products being irradiated under the electron beam, is a critical sub-system of in industrial accelerators. Failure Mode & Effects Analysis has been performed and it is identified that the titanium foil in beam scanning system is considered as weakest link affecting the availability of the system. This paper focuses on the beam scanning system of a 1 MeV DC Accelerator, to analyse the failure of a punctured titanium foil window, through which the beam emerges for irradiation. Analysis through SEM analysis and Raman spectroscopy have been conducted and results are discussed here. Mechanistic model for Ti grade 2 window has been developed and failure probability of the foil has been estimated. Using this estimation, Bayesian network has been developed, with operational data and expert judgement. Mitigation techniques are recommended to ensure the targeted availability of the accelerator.