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Geiger Counter Articles from the Uranium Rush

I ran across a couple of Geiger counter circuits while preparing the Carl & Jerry books a few years back, but it wasn’t until I went looking in Google Books for other articles that I got a sense for the time period 1950-1960, when there was a certain Uranium madness in the air. At first it was about prospecting, but later on as the 50s drew to a close, it was mostly about fallout.

There were articles not only on building Geiger counters, but also reviews of commercial units and practical tips on how to search for the minerals. Sometimes it was a cover story (as with Popular Electronics for July 1955; scroll down) but mostly it was just a part of the electronics hobbyist zeitgeist in that era. There was a certain grim exuberance about it all: The evil Soviet Union was breathing gamma rays in the faces of our collective cultural consciousness, and we were ready to respond with our archetypal American can-do spirit. Some of us understood that the unspoken clause after “duck and cover” was “and die.” Most, I think, did not. (Especially naturally optimistic 11-year-olds like me who just wanted to build a cool gadget with a Geiger tube he already had.)

So below is a list of the construction articles I’ve discovered for Geiger counters in the 1950-1960 era. Many are on Google Books, and I’ve posted the circuits from a couple of the others. If you have any more not listed here, please pass along links or scans so I can add them. I’m considering a standalone Web article for my Junkbox site on building “legacy” Geiger counters based on my current experience, so whatever you have that might be relevant, please share.

  • Popular Mechanics, February 1949: “How to Build a Geiger-Muller Uranium Survey Meter“. Brute force power supply consisting of three 300V batteries in series! Uses K-EX GM tube in series with headphones. No audio amp.
  • Popular Mechanics, July 1950: “Uranium Survey Meter With Audio Amplifier.” Much like February 1949 PM item, plus an audio amplifier. Uses CK-1021 GM tube (others are suggested as usable) and a 3V4 battery miniature tube for audio, which requires a 1.5V filament supply and a 45V plate supply.
  • Popular Science, April 1955: “Prospecting with a Geiger Counter.” Uses a CK-1026 GM tube, with HV generated by a pushbutton interrupter. 3S4 tube audio amplifier. Basically the same circuit as in Alfred Morgan’s Boys’ Second Book of Radio and Electronics.
  • Popular Science, May 1955: “Super Geiger Counter You Can Build.” Ambitious circuit with six (!) GM tubes in parallel plus a 2-tube audio amplifier, and a vibrator high-voltage supply. The GM tubes are all Anton 310 units. Has an averaging count meter.
  • Popular Electronics, July 1955: “Home-Built 700V Geiger Counter”. Two circuits, both using batteries (300V + 67.5V) in a simple voltage doubler. (No sparks!) One circuit has no audio amplifier, and the “deluxe” circuit has a 3S4 tube audio amp and an averaging count meter. Both use the Victoreen 75NB3 GM tube.
  • Popular Electronics, June 1956: “Simple Transistorized Geiger Counters”. Calls out either a CK1026 or a Victoreen 1B85 GM tube. Three circuits: two using 300V batteries, and a third with a pushbutton interrupter for HV. Tube audio amps are replaced by transistor amps, using general-purpose devices (2N35, CK722) that are not critical.
  • Popular Mechanics, March 1957: “Prospector’s Partner.” A combination 4-tube battery superhet AM radio (with canonical 1R5/1U4/1U5/3V4 lineup) using a 1B85 GM tube patched into the grid of the first audio stage. Uses a pushbutton interrupter HV supply for the GM tube; 67 1/2 V battery for the radio.
  • Popular Electronics, July 1957: “Geiger Gun”. Compact gun-shaped hand-held counter counter using a CK1026 GM tube, pushbutton interruptor, and 2N107 transistor audio amp. Article is not online, but there are images of the counter as built in a junction box by someone here. (Scroll down.) Circuit is here.
  • Popular Mechanics, August 1961: “Treasure Finder’s Pal.” A combination metal detector and geiger counter. Uses a CK-1026 GM tube and a CK-722 transistor oscillator into a universal output transformer to generate HV. GM tube output is patched into a transistor radio for audio amplification.


  1. Tom R. says:

    Sear’s sold them at Christmas. I remember my parents taking me to the largest Sear’s store in the area back in the 1950’s and they had a large display of Geiger Counters on display with a sales person at the counter demonstrating them. I KNOW it was prior to 1957, when we moved from that area, and I would guess it was most likely between 1952 and 1955 when I would have been between 5 and 8 years old. The sales pitch was definably slanted towards prospecting since there were samples of yellow cake and pitchblend that were used in the demonstration. Even at that age it was enough to draw me away from the toys and electric train displays in another part of the store!

  2. Clarence says:

    I have been toting around an old geiger counter
    for years. It is made by “precision Radiation Instrument inc. Los Angles Ca.
    the model is Professional Geiger counter
    AEC #SMG-49B
    with a Raytheon tube ck 1021
    on inspection of the tube it was in pieces
    is there a replacement i could get or have built?

    1. The tubes are out there, but you may have to do something like a saved search on eBay for the string “ck1021”. I have eight or ten such searches stored for all the various things I keep hoping will pop up there, like the Winternacht china pattern that I saw at the Furstenberg china factory in Germany and never saw again.

      Here’s the data sheet for the CK-1021:

      Because it uses the JEDEC Pee-Wee A3-1 socket, you might be able to sub in a couple of other tubes with the same base, like the 75NB3, which has about the same spec voltage. The tubes are not complex (they’re basically gas diodes) and if the voltage isn’t too low you should get some signal. I used the 75NB3 in my lashup Geiger counter circuit, and I’ll bet that it would work electrically if the physical tube isn’t too long to fit in the probe housing. The CK-1026 is a whole different shape and won’t work for you. Those are the only two tubes I know much about. Sniff around; if the recent Japan problems haven’t spurred demand for the tubes, you should find one on eBay before too long.

      1. Clarence says:

        Thanks Jeff
        on the info. saving the old probe housing for history i’l put it aside if I cant find the replacement tube. and have a new probe housing machined to fit a replacement tube.
        and see if it works .
        untill I find an oem replacement.
        more searching

    2. Gregory Zalaskus says:

      I have a Raytheon CK 1020 never used in the original box if you or someone you may know may be interested. Just lt me know at

  3. Dr. Albert F. Sefl says:

    Thank you for the synopsis of articles.
    I built my first gieger counter from an article in Popular Electronics and am searching for the issue. The HVDC for the 1B85 tube is derived from an inverter circuit run off 2 D cells. The output of the tube goes to a 2 transistor amplifier with speaker and a meter that was added in a later update article. The amp and meter circuit is powered by 3 AA cells. I still have the unit but the HV selenium rectifier may have died and will need replacement.
    At the time, 1957, my parents took me across the country through Nevada and Utah. How excited I was to be able to register the fallout from some of the atomic tests. Isn’t is amazing how a 10 year old kid could get excited about being irradiated? I also still have my collection of ‘HOT rocks’ but store them away from people in a shielded box. With the work I did, my lifetime exposure to ionizing radiation has been substantial; but, all my cancers are skin cancers from too much California sun!
    Kindest regards to all, Dr. S.

    1. I don’t have that article scanned yet, but I may simply not have run across it. I have all Popular Electronics issues from V1N1 (late 1954) through 1966 or so, but they’re in boxes right now and I can’t flip through them easily. Is there anything you can tell me that might narrow down the date? When I get my family room recarpeted and the mags go back on the shelf, I’ll find it and scan it for you. Anything you can remember about the circuit would be useful. Once I find it, I’ll also add it to the list in this entry. Thanks for writing!

  4. Steve sheriff says:

    I have a Precision Radiation Instrument Model 107B. Are there any known batteries out there? Not just the main battery but all batteries…all I have been able to google is the manual…which I already have…any help?

    1. Unusual batteries for old gear like that are almost impossible to find. I inherited a classic WWII mine detector from my uncle and gave it away because I could never find usable batteries for it. You just have to keep sniffing around. Good luck with it, but be prepared for a long hunt.

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