Geiger counters aren't Universal. I have one of the Amazon ones but without a pancake sensor it will not detect Alpha radiation so it depends what you're trying to detect. (the more expensive ones do/have it as an option)
EDIT: Checked OP's post history, I think I know why, PM me if you want to borrow it. I have this one: https://www.amazon.com/gp/product/B071JWB7TJ/ref=oh_aui_search_detailpage?ie=UTF8&psc=1 in downtown DC
I used mine to see how much radiation we get on long haul flights for fun and don't use it much.
I got mine from Amazon https://www.amazon.com/dp/B071JWB7TJ?ref=ppx_pop_mob_ap_share
The one I have has a USB connection which can be connected to a USB power adapter cord: https://www.amazon.com/dp/B071JWB7TJ?psc=1&ref=ppx\_yo2ov\_dt\_b\_product\_details
Look for radiation meters on Amazon. Here is a good one to get you started. GQ GMC-500Plus Geiger Counter Nuclear Radiation Detector Monitor Dosimeter, White https://www.amazon.com/dp/B071JWB7TJ/ref=cm_sw_r_apan_i_SM509HF0SQPRXJSQZEXV
Found it for anyone wondering GQ GMC-500Plus Nuclear Radiation Detector Monitor Dosimeter https://www.amazon.com/dp/B071JWB7TJ/ref=cm_sw_r_apan_glt_fabc_GP8FJBESPX160X1RYGE1?_encoding=UTF8&psc=1
Maybe something like this?
GQ GMC-500+ Geiger counter
https://www.amazon.com/dp/B071JWB7TJ/ref=cm_sw_r_cp_apa_fabc_zhO4FbK72ZRGC?_encoding=UTF8&psc=1
What's your budget?
On the cheap you could grab a GQ GMC on Amazon. They're around $100 and probably geared towards low end, "fun" measurements.
https://www.amazon.com/GQ-GMC-500Plus-Radiation-Detector-Dosimeter/dp/B071JWB7TJ
I'll always recommend a Ludlum 44-9 GM probe with a Ludlum Model 3 meter for "real" measurements. Seems like they go on eBay for a few hundred. Be careful with high voltage though, and be aware that the mylar window can be punctured and need to be replaced.
https://www.ebay.com/bhp/ludlum-model-3
There's also the bGeige nano if you want to spend a bit more and have some fun snapping it together for $600, or you can get it shipped assembled for $1,500.
Not all radioactive materials have short half-lives. Time to get one of these to make sure!