DIY Geiger counter + smartphone app
john_s
Posts: 369
See http://www.radiation-watch.org/
According to http://www.newscientist.com/blogs/onepercent/2012/02/diy-geiger-counter-smartphone.html
"They have devised a way for people to construct their own smartphone-compatible Geiger counter at home. Pocket Geiger uses 8 photodiodes to detect the radiation, aluminium foil to screen alpha and beta particles, and a plastic "Frisk" sweet box for the housing. The total cost is just $46. ..."
According to http://www.newscientist.com/blogs/onepercent/2012/02/diy-geiger-counter-smartphone.html
"They have devised a way for people to construct their own smartphone-compatible Geiger counter at home. Pocket Geiger uses 8 photodiodes to detect the radiation, aluminium foil to screen alpha and beta particles, and a plastic "Frisk" sweet box for the housing. The total cost is just $46. ..."
500 x 780 - 286K
Comments
Very interesting. But why would they need anything to block the alpha and beta particles? I would think the plastic box would be good enough to block all alphas and probably most Beta particles. Besides, it might be more useful if you can measure some Betas, too. I can't read the Japanese, so maybe I'm missing something here about the foil shielding.
Could it be to target the stuff that it still a hazard this long after the initial event? I thought I read something about many of the initial hazards being short lived, and some of the longest lived hazards being of a particular type, or the alpha and beta particle are at low energy in the later products. Is it the gamma particles that are the big problem?
My point is that the plastic housing will block out all alphas and probably most of the betas, so why would adding foil make any difference to filtering them out? If you have 1 inch of armor that can stop all the bullets being shot at you, what good is adding another 50 inches of armor to stop the same bullets? It looks like overkill to me.
However, perhaps they are slowing down the gammas with the foil, trying to create a splatter of other particles that the sensor can detect??? Too bad I can't read Japanese. I'd like to know what the sensor is.