Okay, so I stopped the scintillator test a while ago. It's pretty apparent that the frequency of positive signals is much higher with higher temperatures, so there's a thermal effect going on that likely swamps any muon scintillator signal, if any. At this point, I can't tell whether the thermal effect is in the electronics or if there's some sort of thermal-fluorescence in the scintillator that is being picked up by the light sensor. Maybe I'll figure out how to test which it is some time later.
