May
31
2011
1

СБМ20 / CBM20 Geiger Müller Tube specifications

I managed to find out some information on the СБМ20 Geiger Müller Tube.

I tracked down the following image on Google Image Search…

With the help of a Russian speaking coworker, I was able to find out the most important specs for this tube.

Nominal working current: 400 volts
Minimum plateau length: 100 volts
Maximum plateau slope: 0.1% per volt (10% per 100 volts)
Working range (min): 0.004 mkR/s
Working range (max): 40 mkR/s
Minimum life: 2*10^10 pulses

Hopefully this will help someone else.

Written by John in: Electronics,Geiger Counter,Projects |
May
10
2011
0

A working Geiger Counter

I managed to get the Geiger counter kitset working.

I believe it was a problem with the high voltage leaking through some flux. Either way, a good cleanup around my solder joints seemed to fix the problem.

The Geiger Müller tube is a is a Russian model, marked with the code СБМ20 – There are lots of results on google for searches for “CBM20″, but very little of use regarding the actual specs of the tube.

I’ve been trying to measure the voltage across the Geiger Müller tube. It turns out that with no capacitor regulating the high voltage, the 10MΩ internal resistance of my multimeter and oscilloscope is enough to drop the voltage significantly. The normal way to get a reading is to add 90MΩ in series with the meter. This effectively creates a 10:1 voltage divider while increasing the total resistance of the measuring circuit to 100MΩ.
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Written by John in: Electronics,Geiger Counter,Projects |
May
03
2011
0

Assembling the Geiger counter

The Geiger counter kitset arrived about a week ago, but I’ve been really busy and unable to find the time to assemble it.

Things in Japan have quietened down (at least in the news), but I’m sure it would still be a good idea to monitor radiation.

The PCB looks tidy, but without a solder screen, may require a bit more heat to solder everything on.

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Written by John in: Electronics,Geiger Counter,Projects |
Apr
17
2011
0

Geiger Counter Project

I’ve wanted a working Geiger counter for a while. It seems like it would be rather handy to have one as a random number generator, and another to install inside a weather station to monitor local radiation levels.

With what’s been going on in Fukushima, I decided it was time to start the project.

Spark Fun have been out of Geiger counter kits for a while and I wasn’t quite ready to just buy a Geiger Müller Tube on ebay and design my own power supply, so I placed an order with Electronic Goldmine a few weeks back.

The courier company has attempted to deliver it, so hopefully I’ll be able to write more soon. In the mean time I’ll spend some more time researching exactly how these things work.

Written by John in: Electronics,Geiger Counter,Projects |