They are unused, I gather they get that nickname because they are everywhere in the area of Nuke research reactors
Their "Real" use in life is to put samples/objects that need irradiation for either sterilization or isotope change, and blow them via pneumatic tube into a research reactor. The "rabbit" is left in the reactor the right amount of time, then blown out the other side. He had about 6-8 cases sitting next to the front door - something like 100 in each case, and $5 for a case. And yeah, they check everything coming into the store with a Geiger counter, they still sometimes get old aircraft parts with radium paint markings - they go into "the collection" (the stuff not for sale)
Wild store. Ed, the guy who runs the place used to work for the labs.
If you need an oscilloscope (used) he might be the place to go - most are OLD ones (things like Textronix 561a, etc - aka early 70s scopes) but working (old tube monsters) - he also has more cryogenic stuff, and high vacuum pumps etc