At least in Europe, there are a lot.

There is even a public realtime map.[1]

Also at least in Switzerland, all old metal scrap companys, waste incineration plant, and so on, have radiactive detectors on the entrance.

[1] https://remap.jrc.ec.europa.eu/Advanced.aspx

[Edit] It seems since April 2026, Switzerland has also a lot radioactive checks in border/customs control and bigger post/packet centres.