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n2ize
02-23-2011, 08:54 PM
Anyone know where you can buy radium glow sheets ?

KG4CGC
02-24-2011, 04:31 AM
try here (http://lmgtfy.com/?q=radium+glow+sheets)
(http://forums.hamisland.net/radium%20glow%20sheets)

n2ize
02-24-2011, 08:18 AM
Unfortunately I can only find the standard luminous glow paper. That might be fine but it has to be charged with light occasionally and the luminosity is not constant.

NQ6U
02-24-2011, 01:36 PM
Good luck with your quest. Radiological materials such as radium are very tightly controlled out of fear of someone gathering enough of them to manufacture a "dirty bomb."

KG4CGC
02-24-2011, 01:44 PM
I was amazed that Hamisland came up on the very top of the list. Hamisland is probably "an island of interest" now.

KC2UGV
02-24-2011, 02:21 PM
I was amazed that Hamisland came up on the very top of the list. Hamisland is probably "an island of interest" now.

And the preview text:

"Anyone know where you can buy radium glow sheets ? ... Contact Jeff and he'll sort it out for you."

Now Jeff is a person of interest :lol:

n2ize
02-24-2011, 09:58 PM
Good luck with your quest. Radiological materials such as radium are very tightly controlled out of fear of someone gathering enough of them to manufacture a "dirty bomb."

Years ago I worked for a company that was licensed to use radium glow sheets. They were used for measurement of thin film metals. I wasn't sure of they are regulated but apparently they are as they don't come up as a standard consumer item. Unfortunately current restrictions make things difficult for experimenters and hobbyists. I was hoping to use a thin strip of radium glow sheet as a source for a true random number generator. I guess as an alternative a sample of Uranium Ore, a tiny chip of Americium, or a dial from an old radium clock, or a lab point source would work fine as a random number source.

NQ6U
02-24-2011, 10:05 PM
How about the radioactive part from an ionization-type smoke detector?

KA5PIU
02-24-2011, 11:10 PM
Hello.

Do you need just a small section?
The US has had concerns over terrorists getting this material.
So, amazing as this must sound, I can get the stuff with ease in Mexico.
China is an excellent source also.

NA4BH
02-24-2011, 11:12 PM
Hello.

Do you need just a small section?
The US has had concerns over terrorists getting this material.
So, amazing as this must sound, I can get the stuff with ease in Mexico.
China is an excellent source also.

Who woulda thunk it?

NQ6U
02-25-2011, 12:26 AM
Good luck trying to get it across the Border, Hajji Rudi.

KA5PIU
02-25-2011, 05:26 AM
Good luck trying to get it across the Border, Hajji Rudi.

Hello.

A single sheet of the stuff is usually 5x7 and costs about a buck.
It is sold to clock repair places as well as was used on some old radios and automobile speedometers.
You carefully pull the radio display apart and pull the paper backing from the brass and clean the brass and spray it with new sealer.
Apply the new paper in place and push the prongs through the paper, just like the original, use the old paper as a loose guide.
How do I know? take a wild guess. ;)

N2CHX
02-25-2011, 07:05 AM
How about the radioactive part from an ionization-type smoke detector?

Heh, I was thinking the same thing and then I read your reply. Great minds think alike.

On that note, I have a cold-war era, government issued portable geiger counter with removable gamma shield if anyone is into that sort of thing and interested.

n2ize
02-28-2011, 07:35 AM
Heh, I was thinking the same thing and then I read your reply. Great minds think alike.

Yes, an Americum source would work well in a random number generator. It emits alpha particles and low level gamma rays so it will work fine with a Geiger tube with an alpha window or a standard beta/gamma tube. Other things that would work. A small sample of uranium ore, uranium glass, radium watch dials, sealed school lab point sources, and even some gas lantern mantles. I used a hand from a radium watch dial when I built a Wilson Cloud Chambre as a high school project. All the above mentioned sources are considered extremely low level, safe, and are exempt from NRC regulations.


On that note, I have a cold-war era, government issued portable geiger counter with removable gamma shield if anyone is into that sort of thing and interested.

I also have one. Perhaps you have the same one I do. Is it bright yellow, have a round silver plate with holes on the bottom along with a sliding metal (beta shield), meter and controls on the top, and made by a company called "Victoreen" ? Is it a model CDV-720 by any chance ?. If so it;s the same one I have in which case it's not a true Geiger counter. It;s a radiological survey meter which uses an "ion chambre" and not a Geiger tube. It was designed to measure very high radiation levels, such as would occur after an attack or a catastrophic accident (i,e, Chernobyl). They are not good for measuring alpha radiation or low level radioactivity. However, if it's a Victoreen CDV-700 then it is an actual Geiger counter. On those models the Geiger tube is housed in a detachable handle and interconnected to the unit by a wire...in which case it can measure low level radiation and alpha sources.

Due to their age virtually all of the cold war meters and counters need to be re-calibrated. Re-calibration of the survey meters in particular, is not something one can do at home. Proper calibration requires a chunk of cesium-137 which is regulated and not something you'd want to keep laying round the house. :)

ab1ga
02-28-2011, 12:15 PM
'IZE:

Way back when Motorola Semiconductor actually made a chip which provided random numbers based on radioactive decay of a source internal to the chip. MotoSemi has since been "parted out" and sold, and I remember that the chip took a long time to generate a single random number, but perhaps it left descendants?

73,

Added in edit: a quick Google search leads to information about hardware random number generators based upon avalanche breakdown noise as well. May be simpler, and yield a higher rate of production.

KC2UGV
02-28-2011, 01:51 PM
If you are not hell-bent on making your own RNG, how's this:

http://www.aw-el.com/

n2ize
03-01-2011, 12:37 PM
'IZE:

Way back when Motorola Semiconductor actually made a chip which provided random numbers based on radioactive decay of a source internal to the chip. MotoSemi has since been "parted out" and sold, and I remember that the chip took a long time to generate a single random number, but perhaps it left descendants?


Not familiar with the particular chip. I guess it was suitable for apps where a rapid stream of product output was not needed. I wonder if there are any floating around out there. On average how long did the chip take to spit out each number ? A



Added in edit: a quick Google search leads to information about hardware random number generators based upon avalanche breakdown noise as well. May be simpler, and yield a higher rate of production.

Yes I've heard of this. There are various sources of entropy that lend themselves toward RNG. Atmospheric noise, etc. On Linux there is /dev/random which generates random numbers based on timings of various sources such as input events, read/write events, keyboard clicks, mouse gestures, etc. Quite interesting.

WØTKX
03-01-2011, 12:44 PM
Tritium, anyone? Ask the gun guys.

KA5PIU
03-03-2011, 01:32 AM
Hello.

Asked around.
In limited quantities radioactive material is not controlled.
But with that said the CAC card that is issued to every US sevice member has a true random number generator.
The way it works is that it uses thermal noise, the same stuff you hear in an un squelched FM radio.
Simply create white noise and use that to generate your numbers, totally random.

ab1ga
03-03-2011, 06:36 PM
Not familiar with the particular chip. I guess it was suitable for apps where a rapid stream of product output was not needed. I wonder if there are any floating around out there. On average how long did the chip take to spit out each number ? A


I remember it taking far too long for my application: something like 256 bits in 18 seconds, but the claim was that it was truly a random number. Using computer system hardware features like keystrokes, disk writes, etc. sounds like it's good enough for most use, but may not pass the most rigorous tests. Even atmospheric noise may not have a uniform distribution; it could be following a power law which would skew results.

73,

KA5PIU
03-09-2011, 08:12 PM
YoHello.

In the world war 2 era there were pure random noise generators, mercury vapor rectifiers.
http://en.wikipedia.org/wiki/SIGSALY
We do not use random, or even pseudo random, but one way codes.
The radio sets are nothing more than clean CB radios that are configured for AM/FM operation and have 2 complete PLL units under "external" computer control.
Usually everything operates around 25 to 30MHz.
But, radium paint is available.
You will need to buy it from outside the US and have it shipped.