Russian Geiger-Mueller Detector
Sulaiman, Wed Sept 20 2006, 09:09PMI just bought a Geiger-Mueller detector cheap (GBP 10.50 incl. p&p) off eBay
It's a Russian model DRSB-01 I and would like to share some information;
The GM tube is CBM20, Ne-Br2-Ar, 78 impulses per micro-Roentgen.
Easily measures background radiation (with external counter/timer)
The thing that surprised me is the Americium241 in smoke detectors.
I'd read that 241Am is an alpha source and GM tubes are insensitive to alpha
so I had quite a surprise when the GM started 'clicking' when brought near
the OUTSIDE of a working smoke alarm.
I took a 241Am source out of another smoke alarm (OK in UK - Illegal in US)
and it easily penetrated a thin steel sheet!
A bit of 'googling' later and I now realise that 241Am also is a GAMMA source!
With a half-life of 432 years, I'm wondering if using nuclear processing waste
for domestic purposes is a good idea?
Anyone got any interresting experiments for me to try?
Re: Russian Geiger-Mueller Detector
Bjørn, Thu Sept 21 2006, 01:05AM
I scraped some material from inside a energy saving flurecent light and covered the Americium and when my eyes had adapted to the dark I could see it glowing in the corner of my eye. It also made a 74HCT14 chip oscillate because it ionised the air.
I also tried if it affected the trigger voltage of a NE-2H bulb and there were no measurable effect. I have tried different methods for generating a very small current to make a microcontroller tick over once in a while with no luck.
You should connect the detector and a GPS to a microcontroller and carry them with you for a week and plot the results on a map.
Bjørn, Thu Sept 21 2006, 01:05AM
I scraped some material from inside a energy saving flurecent light and covered the Americium and when my eyes had adapted to the dark I could see it glowing in the corner of my eye. It also made a 74HCT14 chip oscillate because it ionised the air.
I also tried if it affected the trigger voltage of a NE-2H bulb and there were no measurable effect. I have tried different methods for generating a very small current to make a microcontroller tick over once in a while with no luck.
You should connect the detector and a GPS to a microcontroller and carry them with you for a week and plot the results on a map.
Re: Russian Geiger-Mueller Detector
Dr. Shark, Thu Sept 21 2006, 11:35AM
I think every alpha or beta source also produces some gamma radiation. After spitting out a particle, the nucleus is left in an excited state, so it sends out a gamma photon as it decays to the ground state. I suppose it is rather low energy radiation for Am, so it does not count as a gamma source
Dr. Shark, Thu Sept 21 2006, 11:35AM
I think every alpha or beta source also produces some gamma radiation. After spitting out a particle, the nucleus is left in an excited state, so it sends out a gamma photon as it decays to the ground state. I suppose it is rather low energy radiation for Am, so it does not count as a gamma source
Re: Russian Geiger-Mueller Detector
Wilson, Wed Nov 08 2006, 10:27AM
I thought GM counters worked on the gas inside the tube being ionised, and the free electrons that are liberated being attracted to a positive anode in the centre, producing a small current that can be detected. If such is the case, then alpha radiation, being the most strongly ionising of the 3 *should* produce the most clicks...
Wilson, Wed Nov 08 2006, 10:27AM
I thought GM counters worked on the gas inside the tube being ionised, and the free electrons that are liberated being attracted to a positive anode in the centre, producing a small current that can be detected. If such is the case, then alpha radiation, being the most strongly ionising of the 3 *should* produce the most clicks...
Re: Russian Geiger-Mueller Detector
Sulaiman, Wed Nov 08 2006, 01:26PM
True - IF the alpha particles could penetrate the (thin) metal wall of the G-M tube
which they can't. even a sheet of paper will block alpha particles/rays.
(although the energy of alpha particles may be high
they are relatively huge -alpha particles/helium nucleii)
I now have a ZnS scintilation screen so that I can "see" the alpha particles
with my home made spinthariscope.
Amazing how many particles per second come off a smoke alarm Americium source.
'googling' revealed that Americium is mainly an alpha source
but also a gamma source due to the decay chain.
Sulaiman, Wed Nov 08 2006, 01:26PM
True - IF the alpha particles could penetrate the (thin) metal wall of the G-M tube
which they can't. even a sheet of paper will block alpha particles/rays.
(although the energy of alpha particles may be high
they are relatively huge -alpha particles/helium nucleii)
I now have a ZnS scintilation screen so that I can "see" the alpha particles
with my home made spinthariscope.
Amazing how many particles per second come off a smoke alarm Americium source.
'googling' revealed that Americium is mainly an alpha source
but also a gamma source due to the decay chain.
Re: Russian Geiger-Mueller Detector
Steve Conner, Wed Nov 08 2006, 02:47PM
Wilson: The thing you described isn't a G-M counter. It's called a proportional counter or something. G-Ms use a higher voltage such that any particle that enters it triggers an avalanche of ionisation, breaks the tube down completely, and produces one count, no matter what kind of particle it is.
Steve Conner, Wed Nov 08 2006, 02:47PM
Wilson: The thing you described isn't a G-M counter. It's called a proportional counter or something. G-Ms use a higher voltage such that any particle that enters it triggers an avalanche of ionisation, breaks the tube down completely, and produces one count, no matter what kind of particle it is.
Re: Russian Geiger-Mueller Detector
Tesladownunder, Wed Nov 08 2006, 04:34PM
For sources and experiments, I have a lot on my site. My GM tube has a mica window and is sensitive to alpha emission. I get 80.000 counts/min from an Americium source. This is alpha radiation as it is largely blocked by paper.
Other sources include Uranuim marbles. I also have Yellowcake (processed Uranium ore), Thorium in welding rods, Potassium salts, Mineral sands, Tritium in a glow ring, and Radium from antique watch faces.
Later, I hope to use it as an x-ray detector as it can go down to 7keV.
Peter
Tesladownunder, Wed Nov 08 2006, 04:34PM
For sources and experiments, I have a lot on my site. My GM tube has a mica window and is sensitive to alpha emission. I get 80.000 counts/min from an Americium source. This is alpha radiation as it is largely blocked by paper.
Other sources include Uranuim marbles. I also have Yellowcake (processed Uranium ore), Thorium in welding rods, Potassium salts, Mineral sands, Tritium in a glow ring, and Radium from antique watch faces.
Later, I hope to use it as an x-ray detector as it can go down to 7keV.
Peter
Re: Russian Geiger-Mueller Detector
Sulaiman, Thu Nov 09 2006, 07:58PM
I bought my G-M deterctor on a whim,
a thin mica window would have been much better
- but mine was cheap and interresting and I'm almost finished 'playing' with radioactivity for now.
I did however find radioactive (gamma) uranium glass in one of the local charity (second-hand/used) shops.
Surprisingly a bearded (Muslim) guy going around the shops with a geiger counter (with added earpiece) caused no concern at all.
Sulaiman, Thu Nov 09 2006, 07:58PM
I bought my G-M deterctor on a whim,
a thin mica window would have been much better
- but mine was cheap and interresting and I'm almost finished 'playing' with radioactivity for now.
I did however find radioactive (gamma) uranium glass in one of the local charity (second-hand/used) shops.
Surprisingly a bearded (Muslim) guy going around the shops with a geiger counter (with added earpiece) caused no concern at all.
Re: Russian Geiger-Mueller Detector
ragnar, Thu Nov 09 2006, 10:18PM
LOL, that's because we know you're a mature well-intentioned, non-nutter, probably didn't have that 'twinkle in the eye' and tried not to grin like a serial killer (as I tend to do) whenever you found something radioactive. ^^
Probably also says something good about the shop-owners, too.
The world needs more exemplary people like you. Or at least to open their eyes and recognise them.
http://www.coxandforkum.com/archives/000775.html
ragnar, Thu Nov 09 2006, 10:18PM
Sulaiman wrote ...
...Surprisingly a bearded (Muslim) guy going around the shops with a geiger counter (with added earpiece) caused no concern at all...
...Surprisingly a bearded (Muslim) guy going around the shops with a geiger counter (with added earpiece) caused no concern at all...
LOL, that's because we know you're a mature well-intentioned, non-nutter, probably didn't have that 'twinkle in the eye' and tried not to grin like a serial killer (as I tend to do) whenever you found something radioactive. ^^
Probably also says something good about the shop-owners, too.
The world needs more exemplary people like you. Or at least to open their eyes and recognise them.
http://www.coxandforkum.com/archives/000775.html
Re: Russian Geiger-Mueller Detector
Avalanche, Thu Nov 09 2006, 10:45PM
Many years ago I had an analogue clock kit, which came with a small pot of glow in the dark paint for the numbers on the face. There was probably about 25ml of the paint. Come to think of it, i'm quite surprised they supplied that much radioactive stuff, there was loads left.
Judging by the amount of junk in this house, i'd probably need a geiger counter to find it
Avalanche, Thu Nov 09 2006, 10:45PM
Many years ago I had an analogue clock kit, which came with a small pot of glow in the dark paint for the numbers on the face. There was probably about 25ml of the paint. Come to think of it, i'm quite surprised they supplied that much radioactive stuff, there was loads left.
Judging by the amount of junk in this house, i'd probably need a geiger counter to find it
Re: Russian Geiger-Mueller Detector
Steve Conner, Fri Nov 10 2006, 05:02PM
I totally agree. The world needs more people like Sulaiman and less links to political cartoons in the main forums. (I think the cartoon is great, but that's beside the point.) Let's keep it on topic please!
Steve Conner, Fri Nov 10 2006, 05:02PM
I totally agree. The world needs more people like Sulaiman and less links to political cartoons in the main forums. (I think the cartoon is great, but that's beside the point.) Let's keep it on topic please!
Re: Russian Geiger-Mueller Detector
Banana Man, Sun Apr 15 2007, 09:17AM
It's sad that in the Ukraine, Belarus, and Russia area gieger counters are common kitchen utensils. Sulaiman, I want you to try something the next time you go to medical or dental. Take that device with you for your next dental x-ray and see what you get or if you're feeling evil/helpful you can give it to the dentist so he can see how much he's exposed to on a daily basis.
Banana Man, Sun Apr 15 2007, 09:17AM
It's sad that in the Ukraine, Belarus, and Russia area gieger counters are common kitchen utensils. Sulaiman, I want you to try something the next time you go to medical or dental. Take that device with you for your next dental x-ray and see what you get or if you're feeling evil/helpful you can give it to the dentist so he can see how much he's exposed to on a daily basis.
Re: Russian Geiger-Mueller Detector
Sulaiman, Sun Apr 15 2007, 03:30PM
In the 70's I used to work in the design department for medical and research X-ray machines,
there isn't much 'stray' radiation unless you've got one of the old cobalt type sources.
(if they still exist?)
The newer dental x-ray machines use an active sensor with very low radiation levels.
The risk from mercury amalgam is probably worse for a dentist.
Have you any information to the contrary?
YES, I shall take my GM detector next time just out of interrest.
Sulaiman, Sun Apr 15 2007, 03:30PM
In the 70's I used to work in the design department for medical and research X-ray machines,
there isn't much 'stray' radiation unless you've got one of the old cobalt type sources.
(if they still exist?)
The newer dental x-ray machines use an active sensor with very low radiation levels.
The risk from mercury amalgam is probably worse for a dentist.
Have you any information to the contrary?
YES, I shall take my GM detector next time just out of interrest.
Re: Russian Geiger-Mueller Detector
Banana Man, Fri Apr 20 2007, 11:20AM
I was curious how much they actually leak since I have no knowledge of them at all. If I had one of these devices I would probably carry it around for fun just to see what we're exposed to on a daily basis such as smoke detectors. Might also come in handy to show dumdums that their TV and microwave oven don't emit nuclear radiation. Or maybe I can prove that it does by placing uranium marbles in my pocket or near the device in question. "Oh no, it seems the flux capacitor in your big screen has started leaking deadly radiation. You had better bring it over to my house quick!"
Banana Man, Fri Apr 20 2007, 11:20AM
I was curious how much they actually leak since I have no knowledge of them at all. If I had one of these devices I would probably carry it around for fun just to see what we're exposed to on a daily basis such as smoke detectors. Might also come in handy to show dumdums that their TV and microwave oven don't emit nuclear radiation. Or maybe I can prove that it does by placing uranium marbles in my pocket or near the device in question.
"Oh no, it seems the flux capacitor in your big screen has started leaking deadly radiation. You had better bring it over to my house quick!"Re: Russian Geiger-Mueller Detector
Proud Mary, Sat May 05 2007, 09:08AM
Sulaiman's GM counter is responding to weak low-energy gamma emissions from the smoke detector.
Am-241 emits alpha and gamma radiation of the following energies:
Alpha 5.485 MeV
Alpha 5.443 MeV
Gamma 59.5 keV
Gamma 26.3 keV
Gamma 13.9 keV
SBM-20 is a standard Russian Cold War era metal military GM tube.
Proud Mary, Sat May 05 2007, 09:08AM
Sulaiman's GM counter is responding to weak low-energy gamma emissions from the smoke detector.
Am-241 emits alpha and gamma radiation of the following energies:
Alpha 5.485 MeV
Alpha 5.443 MeV
Gamma 59.5 keV
Gamma 26.3 keV
Gamma 13.9 keV
SBM-20 is a standard Russian Cold War era metal military GM tube.
Re: Russian Geiger-Mueller Detector
atomicthumbs, Mon May 07 2007, 07:01PM
Bjørn, I hope you don't get mercury poisoning.
atomicthumbs, Mon May 07 2007, 07:01PM
Bjørn, I hope you don't get mercury poisoning.
Re: Russian Geiger-Mueller Detector
GreySoul, Fri May 25 2007, 10:08PM
Will Am241 do anything with Europium doped alumina silicate glow in the dark powders, or do I need the ZnS powder as sold at united nuclear?
atomic: good point... there is mercury in a fluorescent tube. Very little, not enough in a single bulb to be too harmful in a large open space like a workshop. unless you're already sensitive to Hg to begin with.
I remember the transition in HS chem classes when then removed the mercury. One year we could play with it in our hands, the next year they were removing thermometers and anything with an Hg tilt switch.
Since then I've not been able to get a straight answer about the real hazards of Hg. The obvious safe path is to avoid exposure, treating it like any other known hazardous material. Personal experience tells me that's probably a bit conservative, but common sense says why risk it? Rational thought says don't be paranoid, just be safe.
But "safe" is a relative and subjective term (is that redundant?).
personally, my safety motto goes... When in doubt: it's probably highly explosive, toxic, and charged to 100KV. All at once. (So wear gloves, glasses, and hold your breath.)
-Doug
GreySoul, Fri May 25 2007, 10:08PM
Will Am241 do anything with Europium doped alumina silicate glow in the dark powders, or do I need the ZnS powder as sold at united nuclear?
atomic: good point... there is mercury in a fluorescent tube. Very little, not enough in a single bulb to be too harmful in a large open space like a workshop. unless you're already sensitive to Hg to begin with.
I remember the transition in HS chem classes when then removed the mercury. One year we could play with it in our hands, the next year they were removing thermometers and anything with an Hg tilt switch.
Since then I've not been able to get a straight answer about the real hazards of Hg. The obvious safe path is to avoid exposure, treating it like any other known hazardous material. Personal experience tells me that's probably a bit conservative, but common sense says why risk it? Rational thought says don't be paranoid, just be safe.
But "safe" is a relative and subjective term (is that redundant?).
personally, my safety motto goes... When in doubt: it's probably highly explosive, toxic, and charged to 100KV. All at once. (So wear gloves, glasses, and hold your breath.)
-Doug
Re: Russian Geiger-Mueller Detector
sparky, Wed May 30 2007, 07:16AM
I often go scrounging for old fire alarms for their radioactive sources :) Damn, and some of the large sources I dig up are pretty insane. I have an industrial ionizing source from a "wide field" smoke detector which comes in a 15 uCi (Am241) --- I have yet to measure the activity... Guessing 450,000 CPM Alpha (50 mR/Hr Gamma) --- maybe a tad off the mark???
Its a fairly hazardous sample, and yes it is VERY well secured - in a vaulted safe.
sparky, Wed May 30 2007, 07:16AM
I often go scrounging for old fire alarms for their radioactive sources :) Damn, and some of the large sources I dig up are pretty insane. I have an industrial ionizing source from a "wide field" smoke detector which comes in a 15 uCi (Am241) --- I have yet to measure the activity... Guessing 450,000 CPM Alpha (50 mR/Hr Gamma) --- maybe a tad off the mark???
Its a fairly hazardous sample, and yes it is VERY well secured - in a vaulted safe.
Re: Russian Geiger-Mueller Detector
EEYORE, Sun Jun 24 2007, 02:34AM
Wow, 15uCi is nice!You ought to be able to do some neato spinthariscope experiments with it...Boy Id love to find something like that. Where DID you find that industrial smoke alarm?
I have some rocks that max out my gieger counter (CDV700). I plan to try some xray photography with them (shield closed readings are over 20mR/Hr), which I will be posting in the projects thread soon.
Matt
EEYORE, Sun Jun 24 2007, 02:34AM
Wow, 15uCi is nice!You ought to be able to do some neato spinthariscope experiments with it...Boy Id love to find something like that. Where DID you find that industrial smoke alarm?
I have some rocks that max out my gieger counter (CDV700). I plan to try some xray photography with them (shield closed readings are over 20mR/Hr), which I will be posting in the projects thread soon.
Matt
Re: Russian Geiger-Mueller Detector
Sulaiman, Sun Jun 24 2007, 09:56AM
The 1 uC Americium is fine for a spinthariscope,
The 'range' of the alpha particles depends on energy, not quantity,
15 uC would probably be too much to see the lovely effects.
Sulaiman, Sun Jun 24 2007, 09:56AM
The 1 uC Americium is fine for a spinthariscope,
The 'range' of the alpha particles depends on energy, not quantity,
15 uC would probably be too much to see the lovely effects.
Re: Russian Geiger-Mueller Detector
dexterslab, Wed Sept 19 2007, 01:32PM
hi guys and my first post here!
just saw this thread and thought i'd post, i bought one of the DRSB-88 detectors (also from ebay) and has proven interesting messing around with it along with an old smoke detector. Alas it's the only thing so far that i found in the house that is more than background.
here's the insides:
note the light flasher (thing with the red lens) is also a tube of some sorts, shame really i was expecting to find just an LED that would allow easy connection to a planned microcontroller project to act as a counter/logger. GM is in the top RH corner covered in wax.
dexterslab, Wed Sept 19 2007, 01:32PM
hi guys and my first post here!
just saw this thread and thought i'd post, i bought one of the DRSB-88 detectors (also from ebay) and has proven interesting messing around with it along with an old smoke detector. Alas it's the only thing so far that i found in the house that is more than background.
here's the insides:
note the light flasher (thing with the red lens) is also a tube of some sorts, shame really i was expecting to find just an LED that would allow easy connection to a planned microcontroller project to act as a counter/logger. GM is in the top RH corner covered in wax.
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