My (now working) Geiger counter is sitting on my desk happily clicking away to itself and I wanted to bring you up to date with the current state of play…
But before we leap into the fray with gusto and abandon, let’s cast our minds back deep into the mists of time and remind ourselves as to how this all came to be…
It all started with my blog Is that a Geiger counter in your pocket or are you just happy to see me? (Click Here to see that blog.) That column introduced a really interesting radiation chart. Also, I mentioned that I live only a few miles from a nuclear power station, and that it might be a good idea to have a Geiger counter, but that they were jolly expensive.
Anyway, one of my friends pointed me at a reasonably inexpensive Geiger counter kit, which I duly ordered, constructed, powered on, and … nothing happened, thereby prompting my blog My Geiger counter doesn’t count (sob sob) (Click Here to see that blog.)
Then things started to get exciting. David Ashton in Australia offered to take a look at my non-functioning unit for me, so I dropped it in the post to him. It seems that the finger of fate was on this whole enterprise (and you have to be very careful where the fates stick their fingers, let me tell you), because I subsequently received two uranium-enriched glass marbles from Nick Bricteux.
This prompted my blog I have radioactive balls! (Click Here to see that blog.) So I had gone from having a Geiger counter but no radioactive source to test it with, to having a radioactive source but no Geiger counter (you couldn’t make this stuff up if you tried).
Anyway, David fixed my little beauty and sent it back to me, along with an article describing everything he had done (see David’s article How to make a Geiger counter count). But the little scamp arrived just as I was heading out of the door to attend DAC 2011. I had a jolly exciting time at the conference, not the least that I met The Woz, but I also couldn’t wait to get back and test the counter, which is what I just did as shown in the following video:
As part of my tests I needed some form of stopwatch. I could have used the one on my Droid smartphone, but it would have been a bit tricky looking at that while jotting down results. Instead, I downloaded a simple but effective (and free) stopwatch application created by Keith Vertanen onto my PC. This made it much easier to keep one eye on the clock and the other on my notepad (of the pen and paper variety).
The result was a background count of 34 events per minute. This rose to 44 events per minute when I put a container of “No-Salt Salt” next to the counter, which is about 30% higher than background radiation alone. Next, I placed both of my radioactive marbles next to the counter, which resulted in spurts of events that were so fast I couldn’t accurately capture them with pen and paper. Using only one of the marbles, however, returned a count of 53 events per minute, which is about 55% higher than the background level.
Finally, I brought a 5 microcurie puck of Caesium-137 close to the counter, which went wild with excitement (so you really don’t want to walk around with this in your trouser pocket). Now I’m just working away at my computer with my counter randomly clicking away in the background – I find it strangely relaxing.
So that’s it … we are at the end of the tale … you are safe … I promise that I won’t regale you with any more tales about my Geiger counter (now I’m turning my attention back to my Atmospherics Monitor project… perhaps we should put David on standby alert :-)
Out of curie-osity (sorry...) I looked up the conversion between Curies and Bequerels and on this site:
I came up with the fact that your 5 microCurie source is equal to 0.000185 of a GigaBequerel. The source I had access to was an 8 GigaBequerel so that makes it 43000 times more powerful that your 5 microCurie one. No wonder the counter got overloaded.
The source I had access to was encased in a lead container (the orange thing you can see in the movie) and it had a lid which went on it when not in use. Even with the lid on, the counter was going wild when it was near it.
"... a background count of 34 events per minute"
As reader Finevlad pointed out in the previous blog entry, the "background count" is not all background radiation, the tubes do self-ionise to some extent. However the difference between your count and mine is interesting, Maybe you should (cautiously) approach the nuclear power station down the road and see if it increases further....
You could also check if all your kids have the right number of fingers and toes.... ;-)
"...my counter randomly clicking away in the background Ė I find it strangely relaxing."
Whatever turns you on, baby.....
"...my Atmospherics Monitor projectÖ perhaps we should put David on standby alert :-)"
That one's already caught my imagination Max, but it's on the end of a wish list about 10 items long at the moment....but feel free....