I've seen these devices in action. There is zero visual feedback when they are operating. Would it be so hard just to have a variable brightness indicator light

I've seen these devices in action. There is zero visual feedback when they are operating. Would it be so hard just to have a variable brightness indicator light coupled with a radiation detector so the operator or assistant would say "damn, is it always that bright?" Something, anything that would give the operator some kind of visceral feedback consistent with the output.