Top 10 Radioactive Electronic Tubes

There are some electronic tubes that contain small quantities of radioactive materials to enhance the internal ionization processes. Such tubes have been used in the 20th century mostly in radar technology. Using a Geiger dosimeter, I have created a top of the tubes in my collection, based on their measured activity.

Some of the radioisotopes used in these tubes are Cesium-137, Cobalt-60, Radium-226, Krypton-85. Because of the small quantities involved and the short half-life, Co-60 and Kr-85 can’t be detected outside the corresponding tubes, because these devices are old and with the passing time the radioactive atoms have decayed to stable elements.

Being mostly used in RADAR technology, the radioactive elements have been added to increase the electronic response by improving the internal ionization processes.

The film shows the following tubes, in order: 11TN40, MA340, 313CD, JAN-8370, JAN-4C35, TG-77, EII-43-100, JAN-346B, 1B26, 1B22





















This article has 6 Comments

  1. Hi Radu

    I watched your video about radioactive tubes – very interesting. Thank you for making this video.

    I have a Western Electric 1B22 and a Westinghouse 1B45. For gamma readings only (no cheating by removing the beta shield!), I have measured:

    1B22: 47uSv/h
    1B45: 150uSv/h

    These measurements were made using a Terra-P dosimeter with the beta shield fitted and in close proximity to the tubes.

    The Westinghouse WL-1B45 is quite a large tube – several times larger than the 1B22.

    The amount of radium used in these tubes varies quite a lot. I have measured one other 1B45 and several other 1B22s. None of them were as high as the above readings. I also had a TG-77 and that was quite low – around 1uSv/h.

  2. interesting. would you post a few pics? would love to see your tubes. maybe you can also include the dosimeter readings.

  3. Hi.
    i watched your top 10 video, very nice!
    i have a “normal” 1B22 tube that measures about 22uSv/h (gamma only) with a scintillation counter. it is from the navy from june 1945 still in it´s box. there is a warning on the box that the tube contains radium and “should be sunk in the ocean or buried” after use. very innovative way of disposal…
    i have another 1B22 tube that looks like the “normal” one but it has “GOVT.” printed in red letters on the glass. this one is much hotter than the other. it measures with the same scintillation counter around 102uSv/h. that´s by far the hottest tube in my collection. too bad that i have no 150uSv/h 1B45 😉

  4. Hi Andreas,

    If you send me some pics with your tubes, I can post them here, with a link to your website.


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