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I own one, it's a $300 Gamma Spectrometer that fits in your pocket. Closest thing I own to a real life Tricorder.

I've tested it out on a smoke detectors. Successfully identified AM-231 and its decay chains from like a foot away. Tested it out on my dad's basement, and it was able to pick up the whole radon decay chain (Thorium, Polonium, Lead, etc.)

It's not a laboratory grade tool. You can point it at radioactive stuff and the spectra lines up perfectly if you Google the charts. There is a community of folks who walk around with them to identify radioactive deposits. I own a GM counter and it's not even in the same league in sensitivity or capability, it would be like comparing a flip phone to a smartphone.

Unfortunately 300$ price point brings up a lot more questions about utility to me.

You can have all the things I mention above at a slightly higher price point.

It is not hard to make these and the really hard part is guaranteeing the quality so they aren’t treated as novelty toys.

Thanks for your detailed comment! Just to clarify, I'm not affiliated with RadiaCode; I've simply developed an open-source Python library to interface with their detectors, making it easier to collect, analyze, and visualize data

Be careful of trade marks! If you are looking for roles check out some of my past submissions and our website.

> c. Are the sensor responses linear?

No. Not even professional geophysical survey spectrometer sensors + interpretation software have a linear response to increased sources.

Two main reasons:

* The electronics to count scintillations (energy bursts at some X keV or MeV energy level) get flooded and overwhelmed; there's a "dead zone" following each detection count, as events increase in number, the percentage of dropped | undetected events increases.

See: Grasty & Minty (1995) page 32 Sec. 4. DATA PROCESSING SubSec. 4.1 Dead−Time Corrections

  Gamma−ray spectrometers require a finite time to process each pulse from the detectors. While one pulse is being processed, any other pulse that arrives will be rejected. Consequently, the ‘live’ time of a spectrometer is reduced by the time taken to process all pulses reaching the analyzer. For large volume airborne gamma−ray spectrometers with their associated high count rates, the dead−time can be significant and corrections must be made, particularly when measuring on calibration pads.

~ https://www.ga.gov.au/bigobj/GA7667.pdf

* Stacking signatures from sources creates complex full spectrums; teasing full spectrums apart to extract component source decay signatures is messy and involves a degree of probablistic guesswork .. not very linear in a real world enviirnoment.

eg: The Cobalt 60 Gamma Spectrum has multiple peaks

The 1332 keV Co-60 peak bleeds into the "fat" K40 Potassium 1461 keV peak, throw in varying amounts of naturaly abundant Uranium and Thorium

https://www.gammaspectacular.com/blue/gamma-spectra/Co-60-ga...

https://www.gammaspectacular.com/blue/gamma-spectra/k-40-gam...

https://www.gammaspectacular.com/blue/gamma-spectra/norm-spe...

and it becomes clear that correctly identifying which elements are responsible for an observed full spectrum is a challenge with often multiple solutions.

The great challenge is correctly "guessing" the original proportions of commonly abundant radiation sources that share common daughter decay products. These are the sources that are listed as having a greater degree of error.