Max's Cool Beans
Comment
jack754
I ordered a kit after Chernobyl, not because of Chernobyl but because we were ...
Max the Magnificent
Good info -- I have a do-it-yourself kit on the way -- I will report back after ...
Is that a Geiger counter in your pocket (or are you just happy to see me)?
Clive Maxfield
3/24/2011 7:29 PM EDT
I was just looking at a really interesting Radiation Dose Chart on the xkcd.com website, which bills itself as “A webcomic of romance, sarcasm, math, and language.” I tell you, this is a really clever site – the cartoons are often extremely thought-provoking, and every now and again they will come up with something like this chart that really makes you think.
The first thing it makes me think is how clever they are to compress so much data into so small a space in such a way as to be so understandable (I now know how much ionizing radiation I can expect to absorb every time I eat a banana, for example).
The second thing it makes me think is that I wish I’d done something like this myself (I think that a lot these days – I see something and think “Wow – that’s such a good idea, I wish I’d thought of that!”)
The third thing it makes me think is that it might be a good idea to invest in a Geiger counter. Also called a Geiger-Müller counter, a Geiger counter is a type of particle detector that measures ionizing radiation.
I know that I’m being a bit of a “worry-wart,” but every now and again I get feelings of grim forebodings – these feelings usually come after watching one of those programs on the Discovery Channel with a title like “Ten ways in which the world could end by Wednesday lunchtime.”
And you start to ponder what would happen if Yellowstone Park erupted in a Super Volcano. And you look at all that’s currently going on in the world, such as the recent floods in Australia and earthquakes in New Zealand and failed nuclear reactors in Japan. And (if you are me) you say to yourself: “Hang on a moment, I live only about 15 miles from the Tennessee Valley Authorities’ Browns Ferry nuclear plant!”
The problem is that I don’t like spending money if I don’t have to. I just did a search for “Geiger counter” on Amazon.com. Anything that looks reasonably good costs anywhere from $350 to $500, which is too rich for my blood (of course, in the event of a major disaster, I would be thinking “I wish I’d purchased that little rascal when I had the chance.”)
I did see a Ghost Meter that was very reasonably priced at only $29.99, but since I don’t believe in Ghosts – and since it doesn’t double up as a Geiger counter – I decided to pass.
Maybe I’ll have a beer instead…
The first thing it makes me think is how clever they are to compress so much data into so small a space in such a way as to be so understandable (I now know how much ionizing radiation I can expect to absorb every time I eat a banana, for example).
The second thing it makes me think is that I wish I’d done something like this myself (I think that a lot these days – I see something and think “Wow – that’s such a good idea, I wish I’d thought of that!”)
The third thing it makes me think is that it might be a good idea to invest in a Geiger counter. Also called a Geiger-Müller counter, a Geiger counter is a type of particle detector that measures ionizing radiation.
I know that I’m being a bit of a “worry-wart,” but every now and again I get feelings of grim forebodings – these feelings usually come after watching one of those programs on the Discovery Channel with a title like “Ten ways in which the world could end by Wednesday lunchtime.”
Click on this image to be taken to the full version of
the Radiation Dose Chart on the xkcd.com website
the Radiation Dose Chart on the xkcd.com website
And you start to ponder what would happen if Yellowstone Park erupted in a Super Volcano. And you look at all that’s currently going on in the world, such as the recent floods in Australia and earthquakes in New Zealand and failed nuclear reactors in Japan. And (if you are me) you say to yourself: “Hang on a moment, I live only about 15 miles from the Tennessee Valley Authorities’ Browns Ferry nuclear plant!”
The problem is that I don’t like spending money if I don’t have to. I just did a search for “Geiger counter” on Amazon.com. Anything that looks reasonably good costs anywhere from $350 to $500, which is too rich for my blood (of course, in the event of a major disaster, I would be thinking “I wish I’d purchased that little rascal when I had the chance.”)
I did see a Ghost Meter that was very reasonably priced at only $29.99, but since I don’t believe in Ghosts – and since it doesn’t double up as a Geiger counter – I decided to pass.
Maybe I’ll have a beer instead…
|
|
|
|
|
Navigate to related information
Max the Magnificent
3/24/2011 7:43 PM EDT
I still think that the way things are going these days it might be useful to have a Geiger counter in the house. So do you know of small, good, affordable unit?
Sign in to Reply
David Ashton
3/25/2011 7:26 AM EDT
Well if I wanted one I'd build it myself! You can pick up geiger tubes for around $ 20. Then you need a power supply giving anywhere from 500V up to 1000V+. Small inverter running off a battery. Then you need anything from an amplifier and a speaker upwards - I'd probably put a monostable and a meter or maybe a counter circuit. (You could find a way to put an FPGA in this bit, Max...) If you're like me, you'd have most of the bits lying around except the tube, so it wouldn't cost a bomb (atomic or otherwise...)
Testing it is a problem - you can buy a bit of Cesium (I'm sure us of British descent call it Caesium?) which has a 30 year half life for around a hundred bucks apparently. Though I'm sure you could find a friendly lab somewhere which would let you test it. However Australia (although they make a mint selling uranium to the nuclear powers) don't have nuclear facilities themselves (we use dirty old coal for power...) so unless the Japanese fallout works its way down here a la "On The Beach" I probably wouldn't need one....
Sign in to Reply
Max the Magnificent
3/25/2011 4:06 PM EDT
My chum Brian just pointed me at some relatively inexpensive Geiger Counter kits (http://bit.ly/dSuRpM).
Now I have to decide which one...
Sign in to Reply
David Ashton
3/25/2011 4:38 PM EDT
There are some good kits there...at those prices, why reinvent the wheel? I'd probably go for the $79.95 one unless I was doing some serious stuff. I see a replacement tube costs the same as the whole kit...such is life these days....
Sign in to Reply
Max the Magnificent
3/25/2011 5:01 PM EDT
The only downside is not knowing how many clicks equate to something serious -- but still and all, it might just be handy to have one of these lying around (I bet I'd be the only guy on my street with one :-)
But I think you're right -- I'll order one and build it and report back in a future blog.
Sign in to Reply
David Ashton
3/25/2011 6:41 PM EDT
My understanding is that geiger tubes will detect beta particles (electrons) and to a lesser extent gamma rays (super high frequency Electro magnetic radiation) but not alpha particles (helium nuclei) as they will not get through the glass of the tube. I think one click equals one particle of a certain energy. Or one pulse of current that produces the click, the more sophisticated (and pricey) ones just have more and more sophisticated ways of counting the clicks.
I guess you could take your counter along to a university lab somewhere and calibrate it. And a man of your calibre could easily get an output and feed it to whatever you want to count the pulses later if you get that into it...
Just been reading up a bit on this on Wikipedia and others, it's a huge and confusing subject. The article on Sieverts (which is what your chart has Max) says that Alpha particles have a much higher weighting than other radiation as regards damage to human tissue (which is what Sieverts are intended to measure) but they don't go very far.
Apparently you should get a background count of a few pulses per minute, caused by cosmic rays and residual radiation in just about everything. I think when you get up to a few clicks per second you need to start worrying.
Sign in to Reply
Joe.Sleator
3/31/2011 5:53 AM EDT
A buddy had given me a GM tube, but it's temporarily lost after moving, so being lazy I just bought another from Vernier. Since the information is quantum, it either clicks or it doesn't. What caused it to click is a bit more complicated. It has a mica window, so if you poke an alpha-source right up to the window it will measure that OK, but alphas don't really go through air very far, they can be blocked by paper. Betas and gammas will go further, so if you put a few mm of aluminium on the back of your instrument and point the back at your source and it still clicks, it was most likely gamma. Uncovered lying in my living room the unit measures 0.120-0.225 micro-Sieverts per hour. Lots of clicks from the thing aren't so scary unless they're coming from YOU, or the clicks are measured AT you from somewhere else. Or worst, the thing doing the clicking is piles of dust blowing around. Only gammas and maybe neutrons go very far through the air. Neutrons aren't as easy to measure with these tools.
Sign in to Reply
Max the Magnificent
3/31/2011 6:26 AM EDT
Good info -- I have a do-it-yourself kit on the way -- I will report back after I've build it and played with it.
Sign in to Reply
jack754
4/7/2011 5:08 AM EDT
I ordered a kit after Chernobyl, not because of Chernobyl but because we were looking for a house to buy and I wanted to check these out for Radon gas. So the Geiger counter had to be able to detect alfa particles. It had a counter that displayed something like 5 and a half digits. It worked for 20 years, but no longer and I'm now looking for a replacement. The tube was supposed to have a nominal output of about 10 clicks/minute. When I first put it together it was giving more than that. I looked at the waveform in a scope and it looked like individual pulses were getting split up and counted several times, so I put in a capacitor to get it to count it as just one pulse, after which the average pulse rate was around 10/min. Here in Norway you can rent equipment to measure Radon gas. So I did this and had my Geiger counter placed beside it, so I found out what constituted an average Radon environment based on the report I got back after the official measurement. I found an old child's watch of the kind that glowed in the dark. This was my alfa source for demonstrations. I have had high metabolism and was finally treated with I-131. After some weeks I was able to check that the radiation did indeed have a half-life of 8 days.
Sign in to Reply