Geiger Tube Anyone?
G4 @uk.radio.amateur Mr G4
I know this is a very long shot, but I wondered if anyone has a
geiger-muller tube lurking anywhere?
Perhaps you may know of a supplier or have an old geiger counter that you
may wish to dispose of?
Mr G4
Barry
Not sure if you've seen these but...
http://www.goldmine-elec-products.com/prodinfo.asp?number=G17365
Barry - N4BUQ
Brian Reay
"Barry" <n4...@knology.net> wrote in message
news:bb482$4b3fd735$4c49dc18$32...@KNOLOGY.NET...
That one only responds to Gamma radiation, not Alpha and Beta particles. A
GM tube to detect all three has a different construction- in particular a
thin window which will pass Alpha and Beta particles which normally are
stopped quite easily.
If the Geiger counter is for private/demo use then sources will be an issue.
Alpha and Beta sources are quite common- smoke detectors use an Alpha source
(can't recall the name) and "Tritium" lights (as found in some signs,
compasses, watches etc.) are Beta sources.
I don't recall any readily available sources of Gamma radiation- although it
is used extensively in medicine.
--
73
Brian G8OSN/W8OSN
www.g8osn.net
G4 @uk.radio.amateur Mr G4
Doesn't seem to look like any GM tube that I have seen before!
Barry
news:X750n.33861$xa7....@newsfe14.ams2...
>>> I know this is a very long shot, but I wondered if anyone has a
>>> geiger-muller tube lurking anywhere?
>>> Perhaps you may know of a supplier or have an old geiger counter that
>>> you may wish to dispose of?
>>>
>>> Mr G4
>>
>>
>> Not sure if you've seen these but...
>>
>> http://www.goldmine-elec-products.com/prodinfo.asp?number=G17365
>
> Doesn't seem to look like any GM tube that I have seen before!
Okay. I don't know anything about them but had recalled seeing the ad for
this one so I thought I'd pass it on. According to a previous post, it
apparently isn't what you might want either.
Good luck with your search.
Barry - N4BUQ
Kenneth Scharf
size of a 50C5 tube, but with a single pin and an aquadag coating on the
outside of the tube. This tube was used in a geiger counter project
that was in one of Alfred Morgan's 'boys books of radio and
electronics', either the 2nd or 3rd book. There were other types of GM
tubes made, but the CK1026 was one of the least expensive and was used
in many simple radiation detectors.
Kenneth Scharf
Geoffrey S. Mendelson
> Once upon a time I recall the type CK1026 GM tube. This was about the
> size of a 50C5 tube, but with a single pin and an aquadag coating on the
> outside of the tube. This tube was used in a geiger counter project
> that was in one of Alfred Morgan's 'boys books of radio and
> electronics', either the 2nd or 3rd book. There were other types of GM
> tubes made, but the CK1026 was one of the least expensive and was used
> in many simple radiation detectors.
The ones used in the 1960's radiation detectors and then sold in a pack
of 3 for $1 at Radio Shack in the late 1960's looked like long neon bulbs
with an extra wire comming out of them. I think they were around two inches
long, but it's been a long time since I've seen them.
Considering that they were designed to detect levels of radiation that would
only exist if you were close to ground zero and poking your head out of
a shelter in the rubble of an east coast (US) city, for all I know they
really were neon bulbs. :-)
Geoff.
--
Geoffrey S. Mendelson, Jerusalem, Israel g...@mendelson.com N3OWJ/4X1GM
New word I coined 12/13/09, "Sub-Wikipedia" adj, describing knowledge or
understanding, as in he has a sub-wikipedia understanding of the situation.
i.e possessing less facts or information than can be found in the Wikipedia.
Kenneth Scharf
> Kenneth Scharf wrote:
>
>> Once upon a time I recall the type CK1026 GM tube. This was about the
>> size of a 50C5 tube, but with a single pin and an aquadag coating on the
>> outside of the tube. This tube was used in a geiger counter project
>> that was in one of Alfred Morgan's 'boys books of radio and
>> electronics', either the 2nd or 3rd book. There were other types of GM
>> tubes made, but the CK1026 was one of the least expensive and was used
>> in many simple radiation detectors.
>
> The ones used in the 1960's radiation detectors and then sold in a pack
> of 3 for $1 at Radio Shack in the late 1960's looked like long neon bulbs
> with an extra wire comming out of them. I think they were around two inches
> long, but it's been a long time since I've seen them.
>
> Considering that they were designed to detect levels of radiation that would
> only exist if you were close to ground zero and poking your head out of
> a shelter in the rubble of an east coast (US) city, for all I know they
> really were neon bulbs. :-)
>
> Geoff.
>
to keep the tube in the dark (inside a black plastic box) and carefully
adjust the voltage across the tube so it was just below the firing
voltage (need a well regulated power supply). Then an alpha or beta
particle might be enough to trigger the tube into conduction. The
sensitivity would be determined how close to the firing voltage the bias
supply was set.
Scott Dorsey
>> I know this is a very long shot, but I wondered if anyone has a
>> geiger-muller tube lurking anywhere?
>> Perhaps you may know of a supplier or have an old geiger counter that you
>> may wish to dispose of?
>
>
>
>http://www.goldmine-elec-products.com/prodinfo.asp?number=G17365
The thing about these is that the glass is designed to block lower energy
radiation. Still, if you want to detect background gamma radiation, it's
not bad. It's probably okay for beta radiation too although you don't know
until you test it.
The market is glutted with Victoreen survey meters. Millions of them were
made for the civil defense folks in the fifties and sixties, and they are
all on the surplus market. They also don't respond well to lower energy
particles, and the scale calibration is useless because the integrator stage
is intended for use in very high radiation environments, but they are very
cheap.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Michael Black
But there was also a need for geiger counters so you could go out and
prospect for uranium. I hadn't given it a lot of thought, until a few
years ago when I found a "magazine" about how to prospect for uranium.
I guess it was published by Fawcett, from the fifties, when it was common
to issue single issue magazines that would be books if they were published
more formally. I have no idea how common the "hobby" was, or how many
geiger counters it sold, but it did seem a big concept for a while.
Robert Heinlein even has some bad guys in one of his juvenile novels
prospecting for uranium on the moon.
There have been solid-state replacements for geiger tubes in recent
decades, but at the moment I can't think of what. Some projects used
existing components that reacted to radiation, but I seem to recall there
were solid-state devices that came along.
Michael VE2BVW
coffelt2
"Kenneth Scharf" <wa2...@bellsouth.net> wrote in message
news:hht10k$2b3$1...@news.eternal-september.org...
I recall being unconvinced when a customer complained that the neon
lamp in his old, rotary disk type depth finder would not work at night
unless he shined a flashlight on it. He was absolutely correct, and
as time went on, we found that as all neon flash lamps (mostly NE2's
and NE51's I think) grew old and weak, they required a little extra
external excitation (flashlight worked ok) to light.
Old Chief Lynn, W7LTQ
Michael Black
It's not so much that they needed light, but they could no longer light
up with the old value resistor. Changing the resistor would have worked,
as did the external excitation with a light.
That was the previous point, you put enough current into the neon bulb
so it's not quite lighting up, and then external radiation would excite
it. It's about setting a threshold right below where the bulb lights
up, and then any external excitation ignites it.
Michael VE2BVW
Peter Dettmann
Probably more a question of voltage supply rather than resistor value,
as unless the neon fires, the drop across the resistor is zero, and so
the resistance value is not controlling the starting.
Peter
coffelt2
"Peter Dettmann" <pe...@aardvark.net.au> wrote in message
news:ega7k5dk4oku75g5h...@4ax.com...
And thus the irritating (and sometimes useful) Neon tube oscillator!
Old Chief Lynn
Brian Reay
"Kenneth Scharf" <wa2...@bellsouth.net> wrote in message
news:hht10k$2b3$1...@news.eternal-september.org...
> You probably could use a Neon bulb as a radiation detector. You'd have
> to keep the tube in the dark (inside a black plastic box) and carefully
> adjust the voltage across the tube so it was just below the firing voltage
> (need a well regulated power supply). Then an alpha or beta particle
> might be enough to trigger the tube into conduction. The sensitivity
> would be determined how close to the firing voltage the bias supply was
> set.
GM tubes don't work quite like that. They have a halogen gas in there as
well to "quench" the conduction caused by the radiation.
Scott Dorsey
Sparkfun.com sells a 712 end-window geiger tube from LND, Inc. It's
sensitive to alpha and beta particles as well as gamma radiation, and
it's something like $70. They have a complete geiger counter kit which
includes a DC-DC converter to get the 500V for $140.
They currently have a promotion going on which is causing their site to be
hammered, but it should be back to normal in a day or two.