I bought an old SMC takumar lens and I’m fairly certain it’s radioactive, but I’m curious exactly how much radiation it gives out.
also, what’s the procedure to be added to the keyholders section? Trying to get updated on the laser status.
Adding you to the members’ group
I could bring my Geiger counter to the space on Tuesday if you want to get your stuff checked.
If your lens is radioactive, it is unlikely to be dangerously radioactive, or leech any dangerous materials as a result. So I do not see any safety concerns with bringing this object into the space.
User sourced Geiger counter world net.
There already is a user sourced Geiger counter world net:
oh that’d be awesome, thanks!
I know it’s not dangerous, but just wanted to see whether it is really radioactive.
The last time that I changed the batteries in the geiger counter, I soldered some wires to some key points on the circuit board so that in the future, I could add a digital pulse counting circuit or something. If I have time, I might work on that next day.
I have an old Kodak with such a lense. I tested it with a Mini 900, equipped with an Alpha/Beta/Gamma probe and it was interesting how the readings were fairly strong smack in front of the camera lense itself but just about non-existant (i.e., background) on the side of the lense, behind the camera, and even at the film position.
But the lens was nicely hot, it is still in my radiating collection.
You have to realize that unless you use a Geiger counter that has been calibrated, all you get is a relative reading.
SDY
Grab a step counter (the thing joggers use on their runs) and epoxy it to your device, then connect appropriately. Fast and simple hack.
SDY
On a related note does anyone know if I can buy/build an inexpensive Geiger counter(kit) locally or over the border this weekend? Most sources I found take 2 weeks minimum for delivery and I don’t want to spend $250+ on commercial counters.
I want this to measure myself(!!) as I am being given some radioactive iodine next week as part of a medical treatment. I’ll be quarantined in my home for 2 days then have to stay 6ft away from others for a week!
I’m curious to see just how radioactive I will be and want to measure the decay over the week so I can determine when I am safe to meet others again.
Thanks in advance,
Ian
What brand/model do you have? I have an operational CDV model 6, among others.
SDY
It’s a yellow translucent RDX Nuclear model.
You could probably build an open-air ion chamber detector yourself, using a tin can as the detector, some silica gel packs to remove humidity in the can, and some common electronic parts to charge up the can (e.g. a high gain small signal amplifier.)
Though I’m not sure about the sensitivity of such a device. Since you want to build this for dosimetry, usually a dosimeter is calibrated against a known radioactive source to compensate for detector geometry and sensitivity (as well as some corrections for human exposure curves e.g. sieverts) You might be able to do the math to estimate what the sensitivity of a specific cylindrical tin can detector would be, based on its dimensions. Then you could use a counting circuit or maybe even a computer soundcard to count the electrical pulses over a period of about 5 minutes in order to get a reasonable sample size (making sure to remain still and at the same distance from the detector every time you measure.) If you plot this information out on a graph you might be able to guess the dosage and the time remaining based on the half life of iodine-131 (8 days) assuming that is what they are injecting you with. Note that iodine-131 decays into xenon-131 and produces gamma and beta radiation in the process.
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If folks ever want an inexpensive Geiger counter, I discovered MCUMall.com in Richmond do several ranging in price from $50 for a “kit” (plus GM tube) up to $150 for one with built-in real-time data logging (every second for 7 days) and a graphical display.
Regards
Ian
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