More Tests and Documentation

A project log for All-In-One Gamma-Ray Spectrometer

More sensitive to gamma radiation than a Geiger counter with the added bonus of telling exactly what's inside your samples!

nuclearphoenixNuclearPhoenix 12/02/2023 at 19:420 Comments

I already updated most of the documentation on GitHub and did a lot of additional testing. I also did most of the things I wanted to do for the firmware and uploaded the first 4.0.0 FW files. However, there are some "bad" news: the energy resolution didn't change a lot if at all when compared to the last revision. More testing revealed it stays much the same, so that was a fluke. But that doesn't change the fact that all the other changes and improvements still hold.

I did some more testing on the energy range and noise levels too and these are my (practical) results:

Can you see the difference? I'm sure you can. The new hardware produces a LOT cleaner spectra and if you look closely you can see the background plateau extends farther to the left after the 32 keV peak up to around 10 keV. This will be more visible in the next images. All of these spectra were recorded using the same crystal, same settings and everything. I recorded my mushroom sample, that's why I got these nice Cs-137 peaks.

As you can clearly see, the peaks are a bit cleaner in general and the measurable plateau extends farther to the left after the 32 keV peak all due to the lesser noise floor. I've now used SMA 8 for both of these spectra. You can also see the reduction in noise in the compton spectrum to the left of the photopeak.

I'm also still currently recording some new example spectra for GitHub and after that I'll check if the two modes of the SMPS on the Pico result in any changes and what averaging setting is the best for energy resolution. I'll keep reporting my findings of course.

Still waiting for the updated OSHWA certification, once that's done, the new PCBs will go into production for Tindie and I will update the PCB files one last time to update the cert mark. I think I already mentioned the updated Tindie price in one of the last posts: it will have to go up by 5 bucks to accomodate the 4L board and the extra components, so the price will be 64.99 USD. I think that's more than fair given all the added value :)

The Tiny SiPM breakout board will get a bit cheaper, it'll be around 1.00 or 1.49 USD. I'm also thinking about adding the temperature corrected standard MicroFC breakout board to the store. Let me know if you're interested in that!