Interestingly they actually exploit these cold temperatures to keep things cool. The Dragonfly Gamma-Ray and Neutron Spectrometer(DraGNS)'s gamma ray detector is mounted outside.[0] In most other probes the detector would need to kept cold with a cryocooler. [0]https://www.jhuapl.edu/techdigest/TD/td3403/34_03-Lorenz.pdf