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.

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 :-)

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.

Once again we use my ~4.3 mCi Polonium-210 source for some charged particle activation. This one gets us an even cleaner and more visible peak, Fluorine-19 in my Sodium Fluoride is much more likely to absorb an alpha particle to initiate the alpha, proton reaction as compared to Sodium-23, and therefore gives us a larger more visible peak as compared to our Sodium Chloride. What’s cool is that we can see the direct comparison of the 1809 keV Magnesium-26 peak from the Sodium, but also the much more prominent 1275 keV prompt gamma from the first excited state of Neon-22 after being activated from the Fluorine-19 in the Fluoride. Here I have also included evidence of why my Radiacode 110 has off center peaks, I believe it needs to be recalibrated. The 803 keV gamma from the Polonium-210 itself is our baseline, if you look at exactly where the peak itself is relative to the exact line of 803 keV, it’s a little off center. This is also true for every other peak by approximately the same amount, hence why the center of the peak isn’t right in where the line is on our expected energy level. The last pictures are the spectrums from the Sodium Chloride experiment after the same full 14 hour scan, you can see that the 1809 keV Magnesium-26 peak is identical on only the Sodium Chloride and Sodium Fluoride run, while its absent with sugar and nothing in the Polonium-210 source.

I was surprised to place my new Alphahound AB+G on an active Fiestaware plate to see the beta count take the CPM lead. Is this to be expected or typical? I was anticipating higher gamma count for some reason, and could rationalize counts all over the map depending on production batch. Comments?

I'm an Electrical Engineering student, and I recently finished building this SBM-20 based Geiger counter using the ESP-32 microcontroller. The perfboard is a 400V boost converter which is actively regulated by the ESP-32.

I bought some samples from FB marketplace and a local antique store. The fiestaware reads insanely hot, and it's a bit scary to be honest lol. The uranium glass and radium watch dial are much more chill.

I'm finishing up the PCB design, and hope to get it all assembled within a month or so! This project has been super fun so far, and I actually can't believe I got it to work lol. The end product should be a small, handheld Geiger counter with a rechargeable battery and whatnot. I'll post pictures of it when it's done! :)

For those of you whom have an alpha hound , how do you like it ? Ive been really wanting to get one but its a steep price and I have nearly every detector I could want. But the form factor and creativity behind it I really like. If I had the disposable income I'd just buy it and add it to the collection of detectors. But maybe I'll get one at some point.

Thanks in advance !

How irresponsible is selling something like this on marketplace? I cracked up when I saw it.

Using my NRD Nuclespot 5mCi Polonium-210 source (~4.5mCi at the time), I was able to bombard normal table salt with alpha particles. Some of the Sodium-23 atoms absorb the alpha particles and pop out a proton, the alpha proton (a,p) reaction. By changing the number of protons, we now have nuclear transmutation from Sodium-23 into Magnesium-26. The excited states of Magnesium-26 release prompt gamma photons at 1133 and 1809 kev which I was able to get peaks of on my Radiacode 110! I also did a run of mostly inert sugar to try and replicate the similar physical barrier between the polonium and the detector, but salt absorbs more gamma so it’s still a little different. But I was able to get those definite peaks in the right spots for just the Polonium with Salt run and not the others, Carl Willis originally did this experiment but with a much better and more expensive HPGe detector. The Polonium-210 is still at around 4.3 mCi, more experiments with it to come!

Was at Trinity site this past Saturday, and took this measurement next to the obelisk with my Ludlum 2241 with a 44-9 pancake probe. More pictures and details to come! Also please feel free to ask any questions, cheers!

i have a GMC GQ 300, but i'd like something more advanced and more accurate.

I did gamma spec of the trinity site because , well , why not? Got lots of attention from people.

Not my day job, just a hobby but was lots of fun meeting a bunch of people.

Plenty of pics of me floating out there now Lol 😆

As promised , I am posting the spectrum. Viewed in Sandia's InterSpec software. Very powerful in the right hands; I'm just a hobbyist though, definitely not an expert. This is also without background subtracted out. I never took a background reading before walking to ground 0
Here are my conclusions based on the time from when the device was tested and likely fission products and activated products.

What I'm sure of :
*Am241 & Pu241 ( The half life of Pu241 is 14 years , its been 81 years since the test , about 3% of Pu241 that was initially still remains)
*Cs137 , I am positive that in that 668.14Kev is supposed to be the 661.2Kev peak, but i think other isotopes or noise overlap, possibly. Or just a calibration issue.
What else is possibly in here based off research and the peaks:
*Ir192 - Possibly from soil , concrete or used somewhere in the device. The meta stable version has a half life of 240+ years and there is possibly 2 peaks for it at 316Kev and 604Kev ? Could just be noise as well but my guess is that it was possibly in the device its self.
*Ni59 - Probably detectable with a more sensitive gamma spec under shielding, The structural steel should have had nickel and molybdenum ( making molybdenum-93)

I want to again say, I'm not an expert. Just doing this for fun. If you want the CSV file I can email it.

If you work for WSMR(met a few scientists there) and would like to send me a sample of soil and or a little bit of the steel to put under a shielded environment, id be willing to do so to get better resolution and less noise but that's a long shot lol. I don't have HpGe in my home sadly , so probably better off sending it to a lab lol .

Thanks for your guys time and great meeting those who went to trinity this year.

It's not something I see too often, but every once in a while I come across an object with exposed radium paint at thrift/antique stores. In this case, it was an old radio with relatively weak paint, but I've seen clocks, watches, dials, etc, with broken or absent coverings where the paint is open to the air.

Is it worth letting store/booth owners know about these objects if I come across them? I won't buy them myself because I strictly don't purchase exposed items, and I worry about others buying things like these, not knowing the risks.

Hello everyone!

I'm not sure what style of detector this is, I'm guessing a dosimeter and a Geiger counter?or if it would even be useful for anything more than a Halloween prop, but I'd like your opinions, because 50bucks seems cheap, as long as new elements are available.

I was bamboozled once by a fake ad, but this one looks much more legit

for example, i want to know what would happen if i shot a thermal neutron of a specific energy at Cs133. is there a place to find it without searching through a bunch of scientific articles?

Hello! I was checking out my Radium-226 (Bezard Compass) spectrum I took a few weeks ago, and noticed there was a peak around 1460~ KeV.

The spectrum lasted for about 3 and a half hours only and I don’t think K-40 had the chance to appear on the spectrum especially when the source isn’t weak. And I didn’t see any trace of Potassium on a short 2,5 hour background spectrum I took a while back. Why is it here now?

My question is could this be a back scatter peak from Bi-214? (3rd pic) Perhaps a Compton edge? Because how the hell am I actually seeing Potassium-40 on a Radium Compass? Am I severely lacking knowledge here? Thank you!

I'm looking for a replacement display for an Eberline PRS-1. If anyone could help me find one, I'd really appreciate it.

I first tried with an SI-3BG, and thought something was wrong with my circuit. It’s just a very insensitive tube and detects one particle like, every other minute.

But then I got a $20 Chinese tube from AliExpress, and it works! Super excited! Making a PCB and an enclosure now. BTW the Chinese tubes use a conductive coating for the cathode and it makes them so pretty

The circuit is the Mighty Ohm counter (schematic open source online) on a breadboard, minus the microcontroller. I still plan to add one for logging, dose calculations and driving a display

Everyone who is interested should try and make one, it was only about $25 usd in parts (most of it the tube), and it put me in a good mood all week.

A while back I had posted some updates on hijacking an Air Things radon meter as an alpha spectrometer. This recaps all of that and shows the final results of the spectrum of mixtures of thoron and radon demonstrating how the Air Things is highly specific to the detection of radon.

Now using this for alpha spectrometry in solid surfaces is not practical as the alpha particles interactions with air cause the peaks to broad so much as to be useless. The Correntium cleverly electrostatically precipitates radon decay products onto the sensor thereby eliminating that issue.

However one could take the probe and sample and place it in a vacuum chamber and likely be able to measure alpha spectrum of other things as well. That may be my next step. But pretty amazed what you can do with this otherwise inexpensive setup.

Hey everyone, final post regarding the radium applicator, the authorities have secured the orphan source! No more risk so, but also my collection of radioactive minerals and other objects, I post my latest photos taken with them! Once again, a big thank you for your answers! Other post will follow with some video's of the devices becoming crazy.

Also the final mass of radium is approximately 130uCi!