geiger tube schematic, help with components sourcing?

Knowledge is obtained by those who survive. :)

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

Doc

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.

BBC40D.tif (8.84 KB)

Is it portable?

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.

Thanks, I will consider it.

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

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?

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

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

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

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

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.

I was referring to hacking... 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

I still have my X-Ray machine somewhere I built from the same Amateur Scientist column. For mine I used a neon sign transformer from an earlier tesla coil...

I do miss the old Amateur Scientist column...

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

Well, a Spinthariscope needs total darkness for I think about ten minutes. Something that is not possible in an antique store.

No it's 10 minutes for your eyes to adjust... I tried to buy the cd... of all the columns, had it once and loved it... there are 3 available through amazon across the US...@ $183.00 ea... Used only.

Doc

For those prices you would be better off purchasing CL Stongs book. Granted it doesn't contain the latter columns, but those weren't as good since they got watered down by the safety police...

http://www.amazon.com/gp/offer-listing/B000ICZI3Y/ref=dp_olp_0?ie=UTF8&condition=all

flamturpolt:

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

Well, a Spinthariscope needs total darkness for I think about ten minutes. Something that is not possible in an antique store.

Not in my experience, I have used them indoors in daylight. Granted the dark it is the better the show!

It's quite possible to get over 1kV (if you wanted to) out of a modified disposable camera flash circuit. I've done it myself and once you know how it's pretty easy to build the circuit from scratch. As you won't be discharging massive pulses from giant capacitors, there's pretty much no chance of you seriously hurting yourself anyway - you can grab the output wires and while it won't be very nice, it's not going to do you any real harm. The poor thing can't supply a lot of current anyway before the transistor gives up and dies.

BulletMagnet83: ... there's pretty much no chance of you seriously hurting yourself anyway ...

While the odds of serious injury are relatively small, there is a reasonable and distinct possibility of serious (up to and including lethal) harm when working with such circuits. Working with high voltage circuits deserve caution and most importantly a lot of reading before hand. If someone doesn't understand how the circuit in question works, they are much more likely to hurt themselves.

I'm all for building stuff from scratch, if your primary goal is learning about how such things work; however, if the primary goal is to use the device it only makes financial sense if you have a fair bit of experience both in constructing circuits as well as in understanding how they work. If you don't you will almost certainly spend more money (not even counting the time involved) getting a working device that even then will not perform as well as what you could have purchased...