We use many types of detectors in nuclear physics, each can do different things well and each has its own downsides. Take the germanium detector a type of detector for gamma rays that has excellent resolution in the energy spectrum (it makes very sharp peaks).
In the old days these came in a form called Ge(Li) (pronounced jelly) detector. These detectors were solid crystals of germanium (a semi conductor like silicon) with lithium atoms dispersed through the crystal. I won’t get into why the lithium was there except to say that it compensated for other impurities in the crystal. These detectors ABSOLUTELY must be kept cold (liquid nitrogen cold in fact (77 K, -196.15 C, -321.07 F)), if they are not kept cold then the lithium could move out of position and destroy the crystals usefulness as a high resolution detector of gamma rays.
In modern times we have developed a much less finicky form of germanium detector called HP-Ge of High Purity Germanium, rather than have lithium atoms scattered throughout the crystal to compensate for the other impurities they simply make the crystal so it has no impurities. Unlike Ge(Li) detectors, HP-Ge detectors can be allowed to come to room temperature when they are not being operated; however, they must be cooled to liquid nitrogen temperatures while they operate (if you really want to know why, ask in the comments) and cycling them down to LN2 temperatures and then back to room temperature repeatedly is not great for them.
