Radiation is perhaps the most misunderstood aspect of prepping. Having the right tools and understanding them is so important.

Ali detectors
https://www.aliexpress.com/item/4000229472051.html
https://www.aliexpress.com/item/32958412308.html
https://www.aliexpress.com/item/33028138934.html

CDV meters on ebay
https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2047675.m570.l1313.TR0.TRC0.A0.H0.Xcdv+radiation.TRS1&_nkw=cdv+radiation&_sacat=0

Calibration by Shane Connor
http://www.radmeters4u.com/calibrate.htm

Iosat at amazon
https://www.amazon.com/s?k=iosat&ref=nb_sb_noss_2

Shane’s main site:
http://ki4u.com/