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Topic: geiger tube schematic, help with components sourcing? (Read 8443 times) previous topic - next topic

flamturpolt

The tube I found detects beta and gamma. Unfortunately no alpha :(. It'll do, though.

Docedison

There is still the point that the OP seems a little inexperienced to be able to play with a flash or any other type of High Voltage supply regardless of it's source. With a great deal of care and knowledge one could put 2 in series and have a 700 - 800 V supply too. BUT NOT with disposable camera supplies as they are only good for 150 - 200 Vout, it's a little bitty tube, doesn't take much to ionize the gas, a 1Kv trigger and about 150 V for the flash. A GM tube is a big neon light... essentially. it measures high energy pulses by drawing enough current to cause the gas to ionize and a combination of the power supply and the gas composition and pressure quenches the ionization and the event is monitored by current sensed in the ground leg of the combination, If I remember what I studied about it in the books long ago... The whole thing using HV power supplies is just too dangerous. I would be nervous to even play with it in a fully equipped lab and I have worked with HV supplies all my life. Better to follow that Elektor photo-diode experiment and build it... Elektor even supplies a kit... of ALL parts.

Doc
--> WA7EMS <--
"The solution of every problem is another problem." -Johann Wolfgang von Goethe
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wanderson


Docedison

Didn't Confucius say that... or was that the one about women flying... <BFG>

Doc
--> WA7EMS <--
"The solution of every problem is another problem." -Johann Wolfgang von Goethe
I do answer technical questions PM'd to me with whatever is in my clipboard

Grumpy_Mike

I designed a simple geiger counter back in 86
The text is here:-
http://www.doc.mmu.ac.uk/STAFF/A.Wiseman/Acorn/BodyBuild/BB_86/BBC40.txt

And the schematic is attached. I used a 240V mains to 3V miniature transformer backwards to provide the HT. The input marked bit 7 is the input for the inverter and can be a PWM signal from the Arduino or a 555 timer. The output marked bit 6 is where the clicks occur.


Grumpy_Mike

Well it was designed to feed into a computer, but given a 12V supply, a 555 oscillator, and LED or phones on the output then yes.

flamturpolt


flamturpolt

I saw a resistor in the schematic that was labeled 4700k. Does this 4700k ohms? By the way, I found some radioactive fiesta-ware today. I also have a video about the fiesta-ware I found today, if anyone is interested.

http://www.youtube.com/watch?v=5kbdnYWxMnA

westfw

Quote
Camera flash supplies are rarely over 350v whereas most geiger tubes need ar least 400v and most are around 500v.

If you follow the actual instructions, they do modify the flash.  The main cap is removed, and the unit is powered from 3V instead of the normal 1.5V, so it at least has potential to produce reasonable voltages.  I couldn't say how well the whole Geiger counter works, but it doesn't look completely bogus.  (I would have put a voltage doubler after the transformer instead.)

http://madscientisthut.com/wordpress/daily-blog/hacking-a-disposable-camera-flash-unit-to-power-a-geiger-tube/

What tube did you end up with?

Docedison

Just proves that you can get stoopider by the day, I hadn't thought about it but now... Boosted B+ in OLD color sets was 'kinda' done that way and even before that... I remember a Zenith Transoceanic that did stack two 67 1/2 V batteries for the Audio stages I think... was one of the early versions with the Loctal tubes. All  tubes from 1949 or 50 I think. I never saw one until I learned to fix them in my early teens.

Doc
--> WA7EMS <--
"The solution of every problem is another problem." -Johann Wolfgang von Goethe
I do answer technical questions PM'd to me with whatever is in my clipboard

wanderson

Given that you are just looking to test fiestaware you may want to consider a spinthariscope rather than jury rigging your own geiger counter.  They don't need batteries, and provide a visual indication of radioactivity.  And they meet one other of your requirements--they are cheap.

http://unitednuclear.com/index.php?main_page=index&cPath=2_12

Docedison

That among several other fluorescent materials is the emitter for a scintillometer, The detector was a Photo multiplier tube, an extremely sensitive photon amplifier, designed it the 1930's and widely manufactured in the 50's through the 90's when the tubes became scarce. Elektor ran a complete Photodiode particle detector recently and there have been at least 3 follow-up articles from other sources since...

Doc
--> WA7EMS <--
"The solution of every problem is another problem." -Johann Wolfgang von Goethe
I do answer technical questions PM'd to me with whatever is in my clipboard

wanderson


That among several other fluorescent materials is the emitter for a scintillometer, The detector was a Photo multiplier tube, an extremely sensitive photon amplifier, designed it the 1930's and widely manufactured in the 50's through the 90's when the tubes became scarce. Elektor ran a complete Photodiode particle detector recently and there have been at least 3 follow-up articles from other sources since...

Doc


The device I mentioned makes no use of a photo-multiplier tube or diode, it requires no power at all.  Simple and easy detection of radioactive materials;

"Way back in 1903, Sir William Crookes was experimenting with the most expensive material on Earth at the time... Radium Bromide.
Working in total darkness, he accidentally spilled a small quantity on a thin layer of a special type of activated Zinc Sulfide (ZnS). To make sure he recovered all of the expensive Radium Bromide, he used a magnifying lens to locate every single speck of it. To his amazement, he noticed flashes of light occurring around each tiny grain of the radioactive material. It was found that the flashes of light were caused by the individual Alpha particles emitted from the Radium compound, striking the activated Zinc Sulfide. The flashes of light were individual photons emitted from splitting atoms. " 

I know that you weren't saying this was scintillator, but I wanted to clarify for those less familiar with the subject.  :)  Indeed one can still purchase scintllator detectors, which can be much more sensitive than traditional geiger counters.

Docedison

I was referring to hacking... <BG> your device, I used them in both high school chemistry and physics classes, Even used one from a 'Foot Ex-ray" machine Geez If I knew then what I know now about that subject you wouldn't even gotten me to Dis-assemble it, let alone turn it into a class project, (personal). A Fluoroscope... We X-rayed almost everything... that would fit, even a really small 8th grade girl... I moved the 'Viewing Screen" down so the whole thing was at waist level, the students in wood shop made a nice box for it with a bracket to hold the 'Screen" and the Visor... I got an A for that class... Probably should have been drowned at birth... Might have been a safer world. I remember an X ray machine I made from a Scientific American "Amateur Scientist" Article... used an 01A tube (1920's triode tube) and some aluminum foil and instead of the spark coil HV Supply I used an old Color TV set... With the 6BK4 pulled (Shunt HV Regulator tube) I got about 40KV and made some great pictures until a neighbor who knew a little more than I did told my parents about the possibility of radiation burns.

Doc
--> WA7EMS <--
"The solution of every problem is another problem." -Johann Wolfgang von Goethe
I do answer technical questions PM'd to me with whatever is in my clipboard

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