geiger-muller-tubes

Vintage (circa 1944) Victoreen 6107 / BS 212 GM tubes & HV PSU I picked up these little gems (and they are!) along with a (matching?) power supply, crystal earpiece and instructions on using them to make a rudimentary Geiger counter. I got them for £26.20 shipped, which I think is great price for these pieces of history, although they were sold as parts and unknown if working/no way to test. As it happens, both tubes work great! One tube came wrapped up in vintage fluff in it's original box and the other tube was loose. The loose tube was in worse condition than the boxed one. The boxed

This is a comparison of 8 glass walled GM tubes, with a SBM-20 as a control. I did this some months ago, but hadn't pulled all the data together until now. Of the eight tubes, four are of the J305 flavour - M4011, J305 (2021 - light sensitive), J305 (2023 - not light sensitive) and one that appears to be a copy, with no markings and came in a cheap FS-2011 Geiger counter. The other four are more interesting, or less, depending which way you look at it. The HH614 is from a pen type counter and is quite small and thin. The remaining three are very low sensitivity tubes designed to be used in

I got these tubes just to see what they were like. I was a little surprised to learn that they are black due to a sleeve of heat shrink over the tube. I had previously thought they were black due to them being an opaque glass, but after peeling a little of the sleeve off it revealed tin oxide coated clear glass, much like the J305. I accidentally rubbed the markings from the J306 when cleaning it, as I have done on a J305. The markings come off very easy with these tubes. Going from top to bottom - J306, J307 then J308. Specs from Alibaba: Below is the background comparison result. Each tube

I have just picked up a couple of Mullard MX-124 GM tubes on ebay for a song! I originally bid a fair amount that I immediately regretted, but when the auction finished I got them for a really good price! There were two tubes in the auction and one came with original datasheet and Mullard guarantee . They are quite unusual in they are designed to detect radiation in liquids. Their construction is like a glass walled GM tube inside a test tube, with a stopper on the end. They are to be used in a vertical position and the liquid poured into the top of the tube and the liquid will run down to

SI-19BG (M) | SI19BGM | СИ19БГМ - Tiny end-window Geiger Muller Tube I received this today after waiting for it to arrive for a couple of weeks. Purchased from Ukraine (via eBay). Not only is it tiny, it is the most expensive GM tube I have bought yet per gram of weight! And it appears to work okay. Sensitive to Gamma and Beta. This tube really is remarkably small. The end window must be no larger than 6mm diameter and the whole thing is only 20mm in length. It's not sensitive and for the couple of minutes I had it on test, the background was about 4cpm and it went nuts with Am-241 being held

Both tubes are α, β & γ - the Philips 18504 can also be used to detect neutrons if the tube is wrapped in Cadmium foil of about 0.5mm. I recently bought a Philips 18504 tube for about £30 (all in) on ebay from Bosnia. It is very similar to the LND-712 so I wanted to compare them. I knocked up a testing rig so the testing could be identical for each tube. All sources were measured at 1cm from the window on the tube. I used a RH Electronics Arduino IDE Geiger Counter DIY Kit ver.2 that I modified to give a pulse output. That goes into an ESPGeiger Log that I used for reading a 5 minute

I have been testing a new GM tube for the past few days, a Robotron 70 013. Its quite a sensitive tube at around 100 CPM for background count. I got to thinking "would a more sensitive tube last as long as a less sensitive tube" so threw some numbers together to find out. My Initial thought was "if the more sensitive tube clicks more, then surely it wears out faster." I'm comparing the SBM-20 (~20 CPM background) with the Robotron 70 013 (~100 CPM background) The SBM-20 has a life of around 20,000,000,000 pulses. The Robotron has a life of around 60,000,000,000 pulses. That settles it, right?

Below is a list of conversion factors for GM tubes that I have been collating over time. They may come in handy if you are building your own Geiger counter and want to convert from CPM (counts per minute) to μSv/h (micro sieverts per hour.) RH = values from RH Geiger SBM20 0.006315; SBM20 0.0057; - RH SI29BG 0.010000; SI29BG 0.0082; - RH SBM19 0.001500; SBM19 0.0021; - RH STS5 0.006666; STS5 0.0057; - RH SI22G 0.001714; = 583.43 SI3BG 0.631578; SBM21 0.048000; LND712 0.005940; SBT9 0.010900; SBT9 0.0117; - RH SI1G 0.006000; SBM-20 - conversion factor 220 CPM -> 1uSv/h (working voltage-

I wanted to see if there was much difference between the sensitivity between a SBM-20 and STS-5 tubes. For a background test I had an SBM-20 running for a while then swapped it for a STS-5. I think the graph says it all. (Note - there was a discrepancy with the initial background test (below). The test was repeated later and the results are shown towards the end.) I took this a step further and compared the two tubes using 13 different sources. In hindsight I should have tested a J305 at the same time. It took a surprisingly long time, so I might set up some kind of testing jig and program an

It seems of late that getting hold of good GM tubes, for reasonable money is a thing of the past. A single SBM-20 on eBay is going for in excess of £150 ($182) and there are hardly any suppliers left for them. Some years back I paid about £13 for a NOS SBM-20. I wish I had the nous back then to buy a large stock of them. I'd have made good money these days! eBay used to be awash with good GM tubes. Lots of regular types, SBM-20, STS-5, LND-712, SBT10A, SBT11A, pancakes, a bunch of Mullard and then a load of quite exotic tubes. Today there is hardly any of those and is covered with cheap