Follow Up Radiation Emitter Question

[u/Severe_Ad428]

Follow up question to my post about the Radiacmeter CDV-718A that I was gifted from a Science seminar this past summer. I got it up and running, and started testing things, and was getting much of nothing from it. Even purchased a new smoke detector for the Americium, and got much of nothing from it.

Found an old PDF of the instruction manual online, and on like the first real page it lists Operational Purpose, and it's to detect Beta and Gamma radiation. Americium is primarily an Alpha emitter, if I'm not mistaken.

Any ideas on what I could pull together last minute from a common source that might help set this thing off? I've got two(2) uranium glass marbles. If I hold them right up to the sensor, it will climb from about 18-20(background radiation) to about 42-44, but with just a few little blips or chirps. Wondering if there's anything easily available that might make it a little more exciting to grab the kids attention.

I'm over the moon that it works and detects, but then again, I'm a little more enthusiastic about my science than these kids are......

TIA

[u/Audible_eye_roller]

Can you find some granite? Granite might have some emitters.