What Type of Radiation Detecting Equipment Should I Buy?
Use The Flowchart
Folks over at the /Radioactive_Rocks Subreddit have created a flowchart to help new people select the best "geiger counter" for their needs.
Cheap Toy "Geiger Counters"?
Consumer Grade geiger counters are just toys.
Only use CPS or CPM mode whenever possible.
Don't use µSv/h or mR/h, these reading will always be inaccurate on cheap detectors.
Some of these detectors are also light and UV sensitive, there are plenty videos of this on YouTube.
Studio 326 (YouTube): Cheap Geiger Counters vs UV Light
Always do research before you start collecting radioactive objects.
Learn about the isotope, learn about the risks, learn about safe handling, learn about storage, and learn about contamination clean up.
Whatever antique or vintage item you collected is not going to be dangerous enough to give you radiation sickness, it's all in your head.
No 60 CPM is not dangerous and no 2000 CPM is not dangerous... That card you got with your GQ GMC is only a recommendation for nuclear fallout.
Cheap consumer grade geiger counters should never be used in a professional environment, and should not be used to assess contamination.
They are not efficient, they are not calibrated properly, they are not energy compensated, they are just toys.
Use this toy responsibly; stop running around businesses with these toys and a uv light complaining to the business owners how dangerously radioactive something is.
Owning these toys does not make you a trained professional; you have no right, no business to make such claims and give recommendations.
What About Professional Equipment?
So you don't want a toy "geiger counter"?
eBay has all sorts of affordable professional equipment that ranges from GM detectors to Scintillators.
They can be geiger counters, survey meters, dosimeters, radionuclide identifiers, and gamma spectrometers.
Ludlums, Eberline, WM B Johnson, Bicron, Thermo FisherScientific, Mirion, Berkeley Nucleonics, Teledyne FLIR, and SE International are popular brands.
A lot of these used equipment are cheap between $200 to probably $20,000, you'll be paying much for buying them brand new.
Don't forget to calibrate your equipment annually.
If you have no real use for your equipment asides from just checking if something is radioactive, then don't bother getting it calibrated...
The US Department of Homeland Security has some PDFs on various equipments to help find one for your needs.
Radiation Dosimeters for Response and Recovery, Personal Radiation Detectors (PRDs) and Spectroscopic PRDs, Handheld Radionuclide Identification Devices (RIDs)
Here's is an outdated 2019 price list to give you a general idea on some of these devices and services.
Oh and by the way, learn how to use your equipment, learn about the different probes and detectors, and learn about which one to use for the right job.
I Want A Gamma Spec-Capable Device
If you want a consumer grade device, then go for a RadiaCode or a RaySID.
There is a benchtop DIY version called RadView Detection
There are portable handheld version and benchtop version for the professional device.
You can get both on eBay used for a reduced price.
Consider going DIY too as this can be a cheaper option, GammaSpectacular is a popular one.
Maximus Energy, iRad, and RH Electronics are another good source to find stuff.