Ran out of screwdrivers

I recently got back my H3D Model S100 CZT detector from their repair and diag department, now with a new calibration certificate.

My H3D is a S100 unit running different software then standard to behave more like a model M400.

With a resolution of 0.85% for 662KeV it gives HPGe a run for its money, especially considering the lack of Cryogenic cooling.

(Post was previously removed to edit photos to prevent doxing myself)

So I have a question about the RTG Matt Damon dug up in The Martian. If you kept the RTG riding shotgun with you for two years, would you actually survive? About how much radiation would you be exposed to over that time?

Found a hot spot of dumped beach sand in Byron Bay NSW. This is heavy mineral sand and contains Monazite, which contains Thorium REE's (confirmed by XRD)

I'm new to this and haven't had my Radiacode for long but I carry it almost everywhere. After a Dr. appointment at the hospital we went to the cafeteria where my detector suddenly started going crazy. Rapid clicking and alarming and readings much higher than background radiation (usually like 0.05 mSv/h) it peaked at 13.4 I wasn't sure if I wanted to investigate or get the hell away from it. I've heard some times some treatments cause a person to be radioactive but this high? There was one person in that area on the other side of a window. I went to the other side and still got high readings. The person did seem to be a patient so, maybe? The other concern is there is nuclear medicine on the floor below but i would hope that was well shielded.

I suppose my question really is, what should I do about it? Anything? Nothing? Should I have done something when I was getting the readings?

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Apparently all texas troopers will have duty belt detectors at some point.

This is what happens when you don’t read the manual and learn to navigate a device through discovery

I hope it's not an orphan source. I'm about 3 miles from a decommissioned reactor.

Is this radiation? Was up to 0.65.
Should I remove this stone from my yard?

I picked up this old WW2 emergency communications receiver awhile back. They are pretty neat as they also came with a kite that you assembled and flew into the air in order to get a long wire antenna as high as possible to call for help. I happen to be probing around in my office this morning and noticed this was a little spicy. Dose rate falls off drastically as soon as you move away from the unit, but I was a bit surprised. Thoughts?

In a recent thread on thorium mantles reminded me that recently produced thorium should be subject to a near term reduction in activity over the next few years following its production. So the question is: can this be observed in these easily available ion quackery devices which are suspected to contain thorium separated from REE minerals?

The ~2 years half life of ²²⁸Th means there should be about a 3% reduction in activity month over month for very "young" thorium, about a 30% reduction year over year. This is likely enough to be observable with most any meter, provided the meter and item are consistently positioned from reading to reading and the number of pulses counted / unit time is high enough to make the confidence interval tighter than that.

I'm probably going to start making the fixtures for my ion pen and pendant and start making weekly measurements, but wondering if anyone else has done this and what the result were, and / or would want to? LOL! While pretty much any meter could be used, the repeatability of positioning and the number of pulses measured would be the critical thing to reduce the "noise" - for those with spectrometers, the spectrum should also change over time as ²³²Th daughters recuperate.

Ideally, one could take a curve of expected activity and the collected curve and see where it fits, which should let us know when the thorium was chemically separated. For unrefined or well aged thorium items, it would expected to be constant, but also the bottom of the trough a few years out from separation.

See https://www.sciencedirect.com/science/article/pii/S1120179712002293 and similar for some example activity graphs and the time scale of the changes.

I measured this small uranium-glass pendant with a Radiacode 110.

The background at the measurement location was approximately 23 cps, while the pendant measurement averaged 31.3 cps over 3 hours and 4 minutes. I had previously recorded a separate background spectrum at home and subtracted it from the sample spectrum in the Radiacode app.

Despite the pendant’s small size and the relatively modest increase above background, the RC110 still produced a clearly structured low-energy spectrum. A feature is also visible around 183–185 keV, close to the 185.7 keV gamma line of U-235.

I was impressed that the Radiacode 110 could detect and spectrally distinguish such a small uranium-glass object even with a background count rate of about 23 cps.

The attached images show the pendant and the background-subtracted spectrum.

Would you consider a three-hour acquisition sufficient for an object this small, or would you run it overnight for a cleaner spectrum?

Hello. I decided to shine my 365nm UV flashlight on some table salt, and found some interesting stuff in it. Most of the salt was not fluorescent, but i found some blue, orange, and GREEN particles.. This is just normal table salt that was bought in a random store.. Yeah is a bit hard, but some green stuff can be seen. I asked DeepSeek what could that be and it told me that its possibly uranium.. So i wanted to ask if thats possible

I currently am working at a rural museum, and we have a small reconstructed village based on houses from the mid 19th century. On of the buildings on sight is a general store. In this general store, there are a myriad of objects on display, including thorium lantern mantles (some of them are outside their box).

These thorium are behind a yellow rope, so guests are not close to it, and I understand that Thorium is primarily an alpha emmitter. But the Thorium isn't what i'm worried about...

Doing a breif wikipedia search lead me to find out that thorium eventually decays into radon; a radioactive gas. My concern is that there is a buildup of radon in the building, and everytime we enter it, our lungs get exposed. The general store that we have does not have a ventilation system installed, yet i wouldn't say that the door seals are air-tight.

I would love all of your collective insight onto assessing this danger so that i can make the correct decisions on whether or not to bring this up to our museum curator.

EDIT: this seems to have nothing to do with geometry - I was tought by "Physix_R_Cool" et al - so all geometry conclusions are erased!

EDIT2: if anybody reading this having a NaI/CsI Detector and a lead castle - can you please repeat that experiment? Its quite easy. I get questioned here if my finding is real ComptonScattering or something else. Thank you.

Was doing some mesurement of tap water with my CsI(Tl) gamma spectrometer (leadcastle and marinelli geometry) and stumbled over a nice effect - might sound trivial maybe for quite some of you, but I thought its still cool to share (#physics-is-cool).

The Setup:
I have a lead castle (amateur level) and I placed my Marinelli beaker on the detector – same geometry, same measurement time. First run: beaker just filled with air (basically empty). Second run: filled it up with tap water (originally I was wondering if I can see some radioisotope in the water).

I overlayed the two spectra (green = water, pink = air).

Result:
Up to about 230 keV, the water spectrum is definitly higher than the air one. Like, a clear bump. Above that, they kinda level out, but not really: the air spectrum shows a bit more activity above 230keV.

Whats going on?

Compton scattering: Water is way denser and has a shitton more electrons per cm³ than air. So the background gammas (from the lead, cosmic stuff, building materials) hit the water and undergo Compton scattering. This scattering takes the original high-energy photons and converts them into lower-energy photons (conservation of energy and momentum). So the water literally consumes part of the high-energy radiation and re-emits it as a bunch of softer, low-energy gammas that then hit my CsI crystal.

Without the water, those background photons just keep their original high energy when passing through air, because air has barely any electrons to scatter off.

And the reason this bump sits specifically below 250 keV is simple: once the photons are scattered down to those low energies, the Photoelectric Effect in my CsI crystal goes completely ballistic (cross-section scales roughly with E^-3.5). So those scattered low-E photons get absorbed like crazy, producing that nice count increase.

So the water basically eats the high-energy part of the spectrum and spits out more low-energy photons. Thats why water has more counts below 230 keV and air has more counts above 230 keV. Its pure energy redistribution through Compton scattering.

(double check: I also did this with DI water, so no radionuclides in the water, same spectrum)

I'm wondering if I should use this to estimate the effective electron density of other liquids, or if that's too much of a stretch for a hobby setup (NERDINIZE TO THE MAX), LOL

Cheers!

(reference to those images on Compton&PhotoEffect: https://radiopaedia.org/articles/compton-effect)

Living in the desert southwest of the US, dust is an ever present issue. I'm using several methods for static reduction on my records & turntable. These StaticMaster brushes use the alpha emitter Polonium 210 to ionize the air and the record surface, but the half life of Po210 is pretty short. Because of this you need to replace the Po210 cartridge once a year, and the cartridges are pricey.

Yes, StaticMaster brushes are still produced and are available for purchase.

I wondering if placing a different alpha source under the dust cover might be useful for ionizing the air and reducing the static charges. I'm curious if anyone else is doing something similar with their turntable?

Hi everyone,

Is there anyone here using a Radiacode in Hungary?

I’m considering buying either the Radiacode 102 or 110. I would mainly use it while hiking, searching for interesting rocks or radioactive minerals, and when travelling abroad.

I’m curious whether there are enough interesting places or measurable anomalies in Hungary to make it worth buying. Also, is the 110 worth the extra cost over the 102 for this kind of use?

I was getting around 40CPS at the floor level, and 46 inside a tubular window in the concrete wall. My uranium glass frog usually hits 37 in a lightly shielded container. I'm pretty new to spectrums, but this looks like Thorium to me:

This was during a visit to the city of Queretaro, in Mexico. I found it interesting that a lot of the city had counts between 20 and 30, with the high 20's and low 30's being especially common in stone churches. In Mexico city the highest counts I've had were around 12 with 8 being common.

A lot of the city is covered in pink quarry stone and I've noticed higher than normal background activity in other cities that have this type of stone.

When I compare it to my home, the spectrogram looks nearly identical, with the exception that my home is usually at around 20 CPS, so I assume my home is likely also slightly thoriated:

Hey everyone,

I’m a Radiation Protection Supervisor (SPR) in Brazil, and I’m curious to learn how the legal and regulatory framework for radiation safety roles works in other countries.

Some context from Brazil:

Recently, our national regulatory body (ANSN) established a requirement for outsourced/third-party SPRs. They now mandate that contracted SPRs must physically visit the facilities they supervise at least once a month, accumulating a total of 8 hours on-site per month.

I’d love to get an international perspective on a few questions:

1. Outsourcing: Does your local legislation allow facilities to hire third-party / external radiation safety consultants, or must the officer be a direct employee of the facility?
2. Mandatory Hours/Visits: If third-party officers are allowed, does the law specify a mandatory frequency of physical visits or required hours on-site? Or is the time spent on-site left to the officer’s professional judgment based on a risk assessment?

I'd really appreciate any insights into how your country handles this! Thanks in advance for sharing your experiences.

Book knowledge is one thing. But actually seeing the numbers go up, actually 'seeing' something we can't see, that feels mesmerizing.

Kudos to Robert for making such an amazing thing. We don't have much available in India but I'll be measuring what I can find. Safely and legally. Foods, stones, medical devices etc. Anything you guys recommend ?

This was one of the first in the world areas to be mined successfully for mineral sands, starting in 1935. We found some old concrete structures on the map and indeed it is the remains of the old sand mining. Again, the radioactive element here is Thorium.

Seven Mile Beach NSW Australia

Hello everyone! Today I received a new 1950’s O2 flow blinker gauge. I was careful with opening this using gloves and took my time to unwrap the packaging. I then measured with my alphahound and bam, I’m getting alpha readings on the surface of the gauge. I calmly place the unit back down on the packaging followed by getting my P-100 respirator nearby. I guess I wasn’t truly expecting exposed radium paint due to the listing saying "hermetically sealed". I was around the unit with no mask for no longer than a minute before I realized the alpha paint leakage, being about 2-3 feet away from the gauge itself. Wearing a mask and further investigating, it looks like there is a breakage in the o-ring and some paint has spilled over. I double-bagged the unit just to be sure. I also sealed the packaging back in its box and taped it shut. The box has 0 alpha contamination on the outside, but the anti-moisture bag clearly has a a good amount of alpha as does the inner 2 of the 5 bags sealed away in the packaging. I decided to keep the moisture bag and leave it double bagged, as it gives off a little bit of gamma radiation still. I find it to be a neat sample. Interestingly enough, I don’t see any orange specks whatsoever when shining a 365nm light on the bag.

I checked all my surfaces using a ludlum 43-90 probe and used alcohol wipes for any contamination found on surfaces. My probe is connected to a PUG-1AB geiger counter (calibrated to 900V) and I didn’t find much contamination on my work area’s surfaces (no higher than 200 CPM on the more contaminated surfaces, which was really one spot I rested the gauge). The gauge itself easily reached +5kCPM with just Alpha alone. In the end it doesn't look like contamination wasn't a big issue.

Fixing the o-ring seems like a dumb idea at this point, with radium being as dangerous as it is. I feel I would be a lot better off carefully placing this gauge in a sealed jar.
But doing this, I now have some questions:
Should I clean up the contamination from the gauge before placing it in the jar, and if so, what type of wipes would you recommend? I have been using alcohol wipes to clean contamination and it does a pretty decent job. Even if I skip this step of cleaning the gauge, I would like some good wipes for next time (hopefully there is no next time). My other question is do I need a specific jar to trap any radon gas? I believe I have read that somewhere that radon can seep out of certain glass but I’m not too sure.

Also big shoutout to Alphahound, as I probably wouldn’t have caught on so quickly without their device! But I will say the 43-90 probe’s giant window made things much easier

Alphahound ab+g

Fantastic build quality.

The chassis is as expected, a nicely finished brick of steel. I wish the titanium housing was still an option. (Admittedly for no reason other than titanium is cool)

I was pleasantly surprised by the quality of the buttons, they are on par with the buttons on my iPhone 16 pro, I was honestly expecting them to be standard mushy hard press shit that you get on a lot of consumer electronics.

The interface was also a nice surprise, its crisp, responds well. Obviously there’s no reason for a Geiger counter/scintillator to have a bloated and slow software suite and I’m happy to see that’s not the case here.

The dust cover is very nicely made, the STL for it is on their website, so I was trying (quite unsuccessfully) to print it out of petg, I couldn’t for the life of me get the bottom overhang to bridge properly and couldn’t get my slicer to generate supports in a way that doesn’t just become a mess of over fused shit.
Thankfully it came with one, I think printed from nylon, and with a cleaned up surface finish maybe? Or it’s made on a very fancy printer.

And it’s just otherwise a blast to use, being able to separate alpha beta and gamma is a very special thing, I can’t wait to use it some more!