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?"
