Can anybody tell me about the failure modes of a (cheap Russian) Geiger
counter? Is leakage of the tube (i.e., continuous conduction rather than
waiting for ionizing particles) a common problem?

(This is not the popular Kvarts DRSB-01; it's a different one.)

mc wrote in message
...
Can anybody tell me about the failure modes of a (cheap Russian) Geiger
counter? Is leakage of the tube (i.e., continuous conduction rather than
waiting for ionizing particles) a common problem?

(This is not the popular Kvarts DRSB-01; it's a different one.)




Don't know about Russian ones but generally its due to failure of the bond
around the mica or whatever window on the end of the tube.

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

On Jul 11, 2:43 am, "mc" wrote:
Can anybody tell me about the failure modes of a (cheap Russian) Geiger
counter? Is leakage of the tube (i.e., continuous conduction rather than
waiting for ionizing particles) a common problem?

(This is not the popular Kvarts DRSB-01; it's a different one.)

Geiger counter tubes are usually for X-ray, Gamma or Beta radiation,
relatively few will detect Alpha radiation. Those that do have very
thin windows at the ionization chamber such that the large Alpha
particle (Helium nucleus) can pass through it and be detected. Such GM
tubes are delicate and usually supplied with little covers for when
Alpha detection is not required and so as to protect the mica window.
Most tubes are filled with a mix of inert gas and a halogen gas... the
latter can sometimes attack the seal around the mica. So, if your GM
tube has a mica window, that would be the typical failure mode. If
not, the wire-lead seals sometimes fail.

http://www.imagesco.com/articles/geiger/01.html

Some basic information here.

Peter Wieck
Wyncote, PA

"N Cook" wrote in message
...
mc wrote in message
...
Can anybody tell me about the failure modes of a (cheap Russian) Geiger
counter? Is leakage of the tube (i.e., continuous conduction rather than
waiting for ionizing particles) a common problem?

Don't know about Russian ones but generally its due to failure of the bond
around the mica or whatever window on the end of the tube.

Can you elaborate? Can it be fixed?

Alpha detection is not required and so as to protect the mica window.
Most tubes are filled with a mix of inert gas and a halogen gas... the
latter can sometimes attack the seal around the mica. So, if your GM
tube has a mica window, that would be the typical failure mode. If
not, the wire-lead seals sometimes fail.

http://www.imagesco.com/articles/geiger/01.html

Some basic information here.

Thanks. I don't think this one has a mica window. I'll check. The circuit
board has had wax poured on it (by the maker, for insulation).

When you say "the wire-lead seals sometimes fail" do you mean they let air
leak into the tube, or they fail in some other way that might be fixable?

On Jul 11, 11:38 am, "mc" wrote:
Alpha detection is not required and so as to protect the mica window.
Most tubes are filled with a mix of inert gas and a halogen gas... the
latter can sometimes attack the seal around the mica. So, if your GM
tube has a mica window, that would be the typical failure mode. If
not, the wire-lead seals sometimes fail.

http://www.imagesco.com/articles/geiger/01.html

Some basic information here.

Thanks. I don't think this one has a mica window. I'll check. The circuit
board has had wax poured on it (by the maker, for insulation).

When you say "the wire-lead seals sometimes fail" do you mean they let air
leak into the tube, or they fail in some other way that might be fixable?

You cannot fix a GM tube that has failed.

Peter Wieck
Wyncote, PA

When you say "the wire-lead seals sometimes fail" do you mean they let
air
leak into the tube, or they fail in some other way that might be fixable?

You cannot fix a GM tube that has failed.

Right, I couldn't quite tell what was being described was a failure of the
tube or of the external circuitry.

I'll check and see if the tube has high voltage across it (apparently not)
and then if high voltage develops with the tube disconnected.

"mc" wrote in message
.. .
"N Cook" wrote in message
...
mc wrote in message
...
Can anybody tell me about the failure modes of a (cheap Russian) Geiger
counter? Is leakage of the tube (i.e., continuous conduction rather
than
waiting for ionizing particles) a common problem?

Don't know about Russian ones but generally its due to failure of the
bond
around the mica or whatever window on the end of the tube.

Can you elaborate? Can it be fixed?



Anything can be fixed with the right equipment and enough effort, but from a
practical standpoint, no. Once the tube is gassy, it's shot.

mc wrote:

I'll check and see if the tube has high voltage across it (apparently not)
and then if high voltage develops with the tube disconnected.

Bear in mind that the typical Geiger tube power supply has a very high
output impedance, and may be loaded down excessively by most common
types of multimeters. If you want an accurate voltage measurement, you
will need something like an electrostatic voltmeter.

Bob Weiss N2IXK