Reliability studies of the custom-designed front-end and ADC chips used for JUNO large photomultipliers electronics

Objective The Jiangmen Underground Neutrino Observatory, which is currently being constructed in South China, will be a cutting-edge liquid scintillator detector for neutrino physics in the coming decade. The read-out electronics will be installed in close proximity to the large photomultipliers and directly inside the water pool surrounding the detector. Once installed, these electronics will not be accessible for repair or replacement; therefore, ensuring their reliability is of utmost importance. A crucial aspect of this reliability analysis involves evaluating the failure rate of custom-designed analog-to-digital converter and front-end chips used in underwater read-out electronics. Methods The Arrhenius model shall be utilized to compute the reliability failure rate value. During ageing, the ambient temperature of the setup system was set at 115 °C. The high-gain and low-gain output channels were chosen as references for detecting failures in the tested sample for front-end chips of Jiangmen Underground Neutrino Observatory, while for analog-to-digital converters, effective number of bits are considered as reference parameters. Results After ageing, all chips were re-measured. The ADC and FEC tests revealed no failures. As a result, the upper limit for the failure rate of front-end chips is 0.43 failures in time, and the upper limit for analog-to-digital converters is 0.42 failures in time at 30 °C. Conclusion The reliability test result shows that custom-designed chips can be used in underwater read-out electronics of Jiangmen Underground Neutrino Observatory.