Screening and Reliability Testing of Beam Loss Monitor Electronics at CERN

A new processing board (VFC-HD) was developed for the Beam Loss Monitoring system at CERN with the purpose to increase the system performance. To fulfil defined reliability requirements during the operation, a screening strategy is defined. Validation tests of pre-series boards during the design phase assured the production quality and additional functional tests during the series-production performed at the manufacturer ensure that quality. After reception of the boards, thermal cycling and a Run-In at operational conditions are executed to eliminate infant mortality failures. The main part of this thesis is the preparation and performance of the various tests, the data acquisition and analysis as well as the identification of occurring failure mechanisms. The results show that screening and accompanying tests are necessary. The functional test filtered around 8 % faulty boards and an additional high temperature test proved the robustness and high design quality of the VFC-HD. The temperature cycling triggered failures for almost 3 % of the tested boards mostly due to cleanliness issues. No hardware failure like a broken solder joint was observed. The failure-free powering at operational conditions determined a current minimum 𝑀𝑇𝑇𝐹 bearing in mind that conservative assumptions were used and possible acceleration factors were not considered.