Hi folks,

I have been browsing through the Cs137 spectra I have done this year - quite some around soil samples, and this fall, also biological tissue (mushrooms). I was quite disappointed as I could not see the famous Compton Edge, Continuum & Backscatter-Peak for Cs137.

You might think this is trivial, as many of you guys have neat check sources (especially in the US). But here in WesternEurope, or at least Germany - to get a checksource is like - forget it - its so overregulated.

So the only option is to find Cs137 contamination in the wild - well "good news", there is plenty of it, thanks mainly to Chernobyl.

But the overall activity is quite low, regional hotspots around here have "only" 800-1200Bq/kg dried soil. The mushrooms I found had 1780Bq/kg.

So the chance to see a Compton-Pattern is bad (at least for me so far).

A good example is image 1 B), this is a 3h spectrum of contaminated soil (all net spectra here). You cant see anything related to Compton-Pattern. I bet this is due to other radionuclide traces in the soil??

The recent 3h mushroom spectrum though gave me hopes: image C). But Interspec does not offer any smoothing function (for good reasons, I know, but sometimes you just need to dig through the noise.

So I made a python script to get a net spectrum, calibrated and annotated - that is smoothed sufficiently: image A). You can just guess that its a ComptonPattern.

So I made a 10h spectrum of the same sample and smoothed again: image D). And with that I would say, yes that looks like Compton-Edge, Continuum and Backscatter. Image 2 shows the position readings at 197keV and 470keV - they should match up to 661 keV - so that could be a fit.

What you guys think?

I apologize this might sound so trivial, but again, for me the first time I see that stuff - so nerd excitement mode engaged :-)

Hi hello, I got a DP-75 from my friend for dirt cheap.as he didn't have the will to fix it. Now it's my issue. I managed to make it alive for 10 ISH minutes by forcing a STS-5 tube onto its probe before I felt a burnt smell when I was trying to see why wasn't the backlight working. A week later I have replaced them electrolyte capacitors that were mostly dead and managed to find and repair a burnt connection. The issue is that I still have the earpiece SCREAMING at me and I could maybe reset it once. I think it's important to also mention that at first I ran it with a external 18V power source and now switched to proper, 3x 1.5 batteries. I really want to get it working but I'm so lost trying to figure out what's wrong. Obviously I haven't checked EVERY component as it also would be kinda impossible due to some being encased and their solder being covered with a protective layer. If it helps, I'll try to answer every question that might help to figure this out and I also know some electronics as I am studying mechatronics. (Attention: some of the things look brownish orangeish because they're covered with the protective layer. There's also two 1k ohm resistors parallel to the ampmeter because it has max 100uA and the original had 250uA max)

My daughter’s high school had their opening night last night. Very tragic and impactful story that happened right here in NJ around 100 years ago.

Have a GammSpectacular? Wish you could directly stream into InterSpec?

I developed (vibe coded...) mcabridge: a lightweight program that takes the audio output of a GS-PRO-V5 / GS-USB-PRO (and possibly other audio-card digitizers), processes the pulses, and pushes every autosave straight into a running InterSpec window via its new MCP API (thanks, Sandia!).

The spectrum updates in place — foreground, background, or secondary lane.

https://github.com/EverythingsComputer/Audio-MCA-InterSpec-Bridge

What it does

• Live push into InterSpec using Sandia’s own MCP interface. No InterSpec code modified — it’s their intended config switch, just driven for you.
• Pause/resume: Freeze counting to calibrate or inspect in InterSpec, then keep accumulating into the same spectrum.
• Energy calibration: Paste the coefficients you fitted in InterSpec, and every pushed file carries them. mcabridge writes them via SpecUtils.
• Standard output files: Writes .spe, .spc, and .n42 files.
• Prebuilt bundles: Single-file builds for Windows and Linux, plus macOS builds (Mac testing feedback wanted!).

Requirements / setup

See the quick guide at the github link.

It uses InterSpec’s recently added LLM/MCP connectivity, so you’ll need the Development build of InterSpec 1.0.14 or newer.

Sandia deserves the credit for making live loading possible in the first place. Token setup is one click inside the GUI: “Configure both”.

GitHub + instructions

https://github.com/EverythingsComputer/Audio-MCA-InterSpec-Bridge

Tested against a GS-PRO-V5; hardware QA is still in progress... the compiled executable should work on windows, mac, and linux, though i am still testing it on all three.