1963 Cold War Military Geiger Counter Teardown (RBGT-62) 

Collaboration actually

@Bear gay dont have wife. Stupid

*collaboration

More saaaaaaaalt, probably, xDD

In the RBGT-62, all 3 transistors are actually PNP. For some reason, the oldest transistors were always PNP. But the newer version RBGT-62A contains 1x PNP and 3x NPN.

This one doesn't have any handle because soldiers used to carry it in a leather case. (it originally came with a case). This one has a phosphorescent scale, but it's not radioactive. It glows just for some time after exposed to light. There's no Ra in it.

The sound of the inverter in the earphone is probably normal. I also hear it in all of my pieces.

Ok, but why is the voltage too low?

It can be a lot of things. Bad battery or poor battery contacts. Poor contact in a pot or switch. It can be damaged transisor in the inverter or damaged diode. It can be faulty regulation tube (the glow voltage regulator). Don't measure this voltage with multimeter, it will make the voltage go lower. The internal resistance of the inverter is very high. The voltage should be 400V, but the voltmeter won't show this. If the needle is at K.N., the voltage is ok.

At first the tube didn't glow , so I turned the black potentiometer. Now it glows, but only a little. The glow is very weak, is this ok?

The gas is probably not neon, so it doens't glow much. It is not designed to produce ligth. So it may be ok.

They are radioactive?

Jo? :)

This doesn't react to sunlight. The tube is made of metal and so the visible / IR / UV light can't get in. The STS-5 tube is sensitive to gamma and beta. I have never tried to detect radon. Maybe an alpha sensitive tube would be needed. Maybe a ionisating chamber would be better. I'm also not sure if the level of radon radiation would be detectable. It is possible that for proper detection you need to absorb the radon (or likely some elements in its decay chain) into some material (carbon?) and then measure the material (carbon).

Well, sun emits some gamma (tiny amounts, to be honest, more with flares), but i guess it's not enough for most tools to notice. Radon, while relatively abundant, have alpha decay, so it basically directly ionizes surrounding air without any noticeable penetration - so, by measuring ionization levels radon amounts can be measured indirectly. And ionization levels can be measured with some kind of magnetic field geterator which will force charged particles from recombining by pulling them in opposite directions - towards some kind of ion detector, probably just grounded probe with ampermeter, and quite possibly some amplifiers in between. But then, noises will most likely just obliterate currents caused by charged particle movement. I guess some other ion detector is needed.

Even a alpha sensitive geiger counter will not detect radon in the air, because there are such small amounts.

Sensitivity is relative. We can ramp it up indefinitely if we can offset the noise.

The headphone plug is simmilar to a mains plug, not the probe plug. The probe socket has 400VDC in it, but it is hard to put a finger into it and there's a very high value resistor in series (I think 10M) anyway. This would only result in 0.04mA through your body. You wont even notice such current.

oops

:)

Those are uranium glass balls/marbles/beads. Those are legally sold and by law they contain less than 1% of uranium, but usually just about 0.1 or 0.2%. They are a safe Geiger counter test source :).

DP-5V Geiger Counter prob radioactive check source Strontium-90 ( Beta )