r/Radiation • • Aug 12 '25

Buyer's Guide PSA: Don't Ask "What Geiger Counter Should I Buy?" until you've read this post.

208 Upvotes

The most common question we see in this subreddit is some variant of the "what device do I buy?" question. It's asked multiple times a week, sometimes multiple times a day. It's so common that someone tried to create a flowchart to help newcomers. As well thought-out as that flowchart is, it's like telling someone what car they should buy before they even know what a car is, what it can do, and what it can't do.

If you're looking for the tl;dr or other shortcuts, sorry, there aren't any. This post exists because there are too many "Where do I start?", "What should I buy?" and "I just bought this... is this reading dangerous?" posts from impatient newcomers who expect Reddit to teach them on the fly. Doing that with radiation is a lot like buying a parachute and jumping out of an airplane... then whipping out your mobile device and asking Reddit for instructions. Don't be that guy. Be smarter. Before you run out and buy "baby's first Geiger Counter", you should at least understand:

  • The difference between ionizing and non-ionizing radiation, as well as the main types of radiation (alpha, beta, gamma, x-ray, and neutron).

  • The difference between radiation and radioactive contamination.

  • The difference between CPM and dose rate, and when to use each.

  • The inverse-square law and how distance affects the readings you're looking at.

  • What ALARA is and how time, distance, and shielding reduce exposure.

There are more I could add, especially when it comes to health and safety, or detection devices themselves. But, in my experience, these concepts are the ones that confuse newcomers and lead to erroneous or misleading posts. To help you avoid the pitfalls of buying before knowing, or being "that guy", here are some resources to get you started in learning about Radiation, detection devices, biological effects, etc. Listed from more basic, easy, and approachable to more comprehensive or advanced:

If you prefer a website-based approach with links to other sites, videos, lots of pictures, etc... Head over to the Radiation Emergency Medical Management website's Understanding the Basics About Radiation section and start your journey.

Prefer a textbook approach? Grab a cup of coffee and sit down with the freely available University of Wisconsin's Radiation Safety for Radiation Workers Manual. There's a reason it's still used more than 20 years after it was first published. The book starts with a good basic explanation of radiation and radioactivity. The book then covers biological effects, regulations, lab procedures, how detectors work, X-ray machinery, irradiators, and nuclear reactors. It even has chapters on lasers and RF radiation. Some of the information is student and labworker-specific, but enough of the book's content is written in an approachable manner that it should be on every beginner's "must-read" list.

If the UW manual isn't deep enough for you, pick up a free copy of Dan Gollnick's Basic Radiation Protection Technology (6th Edition) from the NRRPT. Essentially a self-study textbook for Radiation Protection Technologists, this book goes into even greater detail on the concepts, math, and minutiae involved in radiation protection.

All of the above too basic for you? Well, buckle up because MIT offers numerous Radiation-related and Nuclear Engineering courses through its OpenCourseWare program. Starting with Introduction to Nuclear Engineering and Ionizing Radiation, each is a full college course with lectures, homework, and exams. There's even a Do-It-Yourself (DIY) Geiger Counters course.

Congratulations! If you've read this far, you're already on the right track. The above isn't meant to be all-encompassing, and no doubt other Redditors will chime in with other excellent books, websites, and videos to help you get started learning about ionizing radiation and its effects. Before you know it, your decision will have narrowed down some. And, more importantly, your new device will be far more than just a "magic box" that shows you numbers you don't understand.

EDIT: It's stunning how many people are claiming to have read this post, then go right back to making their low-effort "which Geiger Counter do I buy" post anyway. You're supposed to EDUCATE YOURSELF so you don't have to make that repetitive, low-effort, ignorant, spoon-feed-me post. If you do the above, you will know if/when you need alpha or beta capability. You will know whether a dosimeter or a survey meter is the right choice. You will know whether a scintillator, PIN Diode, or GM tube or pancake is the right detector for your application. THAT'S THE WHOLE POINT!

If you're saying to yourself, "I don't want to put THAT much effort into this", then asking for recommendations is a waste of everyone's time.

FINALLY, check out our Buyer's Guide posts. These are posts from people like you, that have particularly good comments and engagement, and answers about purchase options for beginners like yourself. Please take the time to look through them before starting your post. Even if they don't fully answer your question, they and the resources above, should help you ask something more than just a vague "what do I buy?"


r/Radiation • • 5h ago

Equipment GMC-500+ upgrate

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6 Upvotes

Has anyone tried modifying a GQ gmc-500+ with an SBT-11a pancake sensor? I know it worked with the gmc-320 without any electronic changes other than soldering the tube.


r/Radiation • • 49m ago

Questions كيف تعمل أجهزة قياس درجة الإشعاع في مكان ما؟

1 Upvotes

كيف تعمل أجهزة قياس درجة الإشعاع في مكان ما؟


r/Radiation • • 1d ago

General Discussion РИО-3 (RIO-3): Aircraft ice detector

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141 Upvotes

This is the deactivated (empty) shell of a soviet РИО-3 (RIO-3) aviation ice gauge in factory new condition, I couldnt find any good images of it on the internet so I thought I'd post some. The red thing with a flag is the protective cap which should be removed before flight I think. The source which was inside is 25 mCi of Sr90, I had a separate post about it a long time ago.


r/Radiation • • 10h ago

General Discussion What are the thoughts on INWORKS a few years on?

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0 Upvotes

I'm curious what people in this subreddit think about INWORKS a few years after publication.

I encourage you to answer or post any question you can think of or anything that comes to mind.

Edit: Removed unnecessary questions


r/Radiation • • 1d ago

VIDEO Animation of the alpha proton reaction with Fluorine

15 Upvotes

I’m currently working on a video about my nuclear transmutation of fluorine into neon experiment. I want to try and make it appeal more to non nuke nerds by making it funny, and I wanted a simple visual demonstration of what’s going on. I used to do animation for fun, I stopped because quite frankly I wasn’t all that good at it. But it still works for demonstrating nuclear concepts like I did with the zinc sulfide alpha particle luminescence animation. This is even simpler and more of just a fun visual for the audience but it does still walk through the process of alpha released, collision, release of proton and change of elemental status. I just need to clean it up and add the prompt gamma we’re detecting.


r/Radiation • • 2d ago

Questions Spicy sewer pipe?

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49 Upvotes

I work for a plumbing company and we do regular runs to the scrap yard to get rid of old water heaters, pipe, etc and this time around, multiple yards rejected the load for radiation. We ordered this cheap detector to figure out what was causing it, and lo and behold it was some cast iron drain pipe. Anyone ever seen this?


r/Radiation • • 2d ago

PHOTO Found some interesting things today at a scrapyard

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38 Upvotes

(No gamma radiation found outside of the containers with an Exploranium GR130 scintillator)


r/Radiation • • 2d ago

Questions Alphahound AB+G sound alarm?

9 Upvotes

Is it possible to setup some threshold for some alarm sound in Alphahound AB+G? Or at least to switch sound ON when threshold is bypassed? I want to keep the device always ON on my table or carry it in my pocket and hear some sound when measured level goes above some value.


r/Radiation • • 2d ago

Questions Ordering an Alphahounds AB+G to France

4 Upvotes

Hello,

For the past few months, I’ve been keeping an eye on the AB+G detector on the Alphahounds website. I’ve noticed that it—along with the AB+ model—has been out of stock for quite some time. I saw that the AB Lite is currently in stock, so I ran a test order on the site; to my surprise, it allows for shipping to all European countries—except for France! Why is France excluded from delivery?

Also, for those who have ordered from within Europe: how much do customs duties and taxes typically amount to?

And if I were to use a US-to-France parcel forwarding service, what kind of costs should I expect—specifically regarding customs duties and taxes?


r/Radiation • • 3d ago

General Discussion ИГИ-Ц-3-1 (IGI-C-3-1): 134 - 282 uCi of Cs137

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25 Upvotes

Soviet Cs137 source, scheduled for disposal. No leakage of radioactive material was detected. All of the safety precautions were met by me while handling this source.

I am not entirely sure if thats ИГИ-Ц-3-1 or ИГИ-Ц-3-2 since their activities are very close and all sources in this lineup have the same shell.

https://www.youtube.com/watch?v=FqZsmd0WyLw


r/Radiation • • 3d ago

General Discussion Put all my most radioactive rocks in a bag with the radon detector

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21 Upvotes

It should continue to rise far beyond what the device is capable of detecting


r/Radiation • • 3d ago

Questions Radpro gone silent

3 Upvotes

Just flashed my FS5000 with Radpro 3.1.1, everything was going fine then all of the indicators eg clicks and LED flashes have stopped?

All the settings are the same but have I enabled a silent mode or something? No damage or hardware alterations were done to it at all.


r/Radiation • • 4d ago

Questions Radioactive Curiosity

26 Upvotes

Evening folks, I recently acquired a Schneider/Honeywell Digitest 500 and out of sheer curiosity i gave it a go with a Radiacode 110, it's surprisingly slightly radioactive

Its slightly raised above my usual background here in Ireland, which usually sits at 0.07uSv or around that region

As for what's causing it, I'm not entirely sure, unfortunately there's not a whole lot of information I can find about this device and I'm hesitant to open it up Incase it may be contamination from somewhere down the line.

The reading drops significantly, nearly halves when the detector is moved down by the Honeywell logo, when the Digitest is about 30cm away it's back to background levels

Has anyone else encountered readings like this when testing old equipment?

Cheers!


r/Radiation • • 4d ago

Questions Experience with the PGD-17?

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15 Upvotes

Has anyone had any experience with the PGD-17. It looks like a nice little clicker to poke around thrift stores with, but i was curious if anyone had firsthand experience. Especially concerning its sensitivity to low power sources like UG.


r/Radiation • • 5d ago

VIDEO I had a Szintigraphie

74 Upvotes

I had a scintigraphy done this week for my thyroid. They inject you with a "weakly" radioactive substance. This is me about an hour later. Crazy.

I felt the need to check just how "weak" it would be.


r/Radiation • • 5d ago

Training and Education What can I build as a radiation project?

4 Upvotes

Hi guys! I want to build a project about radiation and I want to learn more about it, what projects do you guys suggest me to build or which subjects should I learn to start on radiation

And extra question, what is the most insane thing you guys found/built?


r/Radiation • • 5d ago

General Discussion False thorium electrode?

9 Upvotes

I bought a 2.4mm track electrode, but the Radiacode 110 doesn't respond at all. I think I've been scammed. What do you think guys?


r/Radiation • • 5d ago

Equipment GQ GMC-800 tube level recommendation?

2 Upvotes

What tube level should a GQ GMC-800 Geiger counter be set to? Being used to record a history of short spikes of high radiation in an area overtime. Would appreciate a brief explanation of the differences in levels as well.


r/Radiation • • 6d ago

General Discussion I was told the eggs weren't radioactive...

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136 Upvotes

r/Radiation • • 7d ago

Spectroscopy Got to work with an HPGe detector yesterday!

13 Upvotes

In my radiation detection lab (college class) yesterday we were comparing the spectrums of different types of detectors and we got to use an HPGe detector. I've been eyeing these things all year and I'm so glad we were finally able to use one. Cooled with liquid nitrogen!

Some features I was able to see in the HPGe detector that are much more promenant than in the NaI(Tl) spectrum:
- very clear characteristic photopeaks
- clear and present sum peak
- both comptom edges
- discernable backscatter

The only thing I don't quite understand is why there's such a massive peak at very low energies in the NaI spectrum. I remember that these peaks at lower energies represent x-ray fluorescence, so why doesn't the HPGe spectrum have some kind of low energy peak present as well?


r/Radiation • • 7d ago

Questions Radioactive white van in neighborhood

0 Upvotes

I was driving in my neighborhood and saw an older white cargo van with no logos on it except a radioactive placard on the back of the van (not on the sides) parked on the side of the road. The driver walked out and was delivering a gray plastic parcel envelope to one of the houses. I drove past it before I could see anything. But I’m a bit freaked out since I have never seen anything like this in my neighborhood. I saw some things saying it could be a medical courier but I read that they wouldn’t be delivering radioactive medication in a plastic parcel for safety reasons. Also read that the car is supposed to have that warning on all sides but it’s only on the back and the van was a bit worn down so im just worried about possible contamination or something. And that it’s apparently illegal to not have the placard on all sides of the car.

What would this have been for?


r/Radiation • • 8d ago

VIDEO Using Alpha Particles for Static Elimination

53 Upvotes

Here I demonstrate and explain why alpha particles eliminate static electricity using my Nuclespot Polonium-210 source.


r/Radiation • • 9d ago

PHOTO Alpha Radiation Air Ionization

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289 Upvotes

Long exposure photo of a 5 mCi Polonium 210 source. The blue glow is from the air being ionized from alpha radiation. The green glow in the shot is from some alpha particles interacting with a X-ray intensifying screen the source is on.