anthonyj

Hi thermonub,

I hope you don’t mind me adding to your thread with a request for some help too, as I am trying to do the same thing, here is where I am:-

I’m using Am241 (33Kbq) from a smoke detector as a source .

I believe you can get very good results from pointing the source at a CCD camera that has the lens removed, loads of blips can be seen and I believe these are individual Alpha particles hitting the elements, the only thing is that the particles eventually destroy the elements and you are left with a continuously speckled picture that I guess over time would become completely white.

I have tried pointing the source at a CCD with the lens on and you can see the low energy gamma rays causing the odd blip (well I assume that’s what they are).

Next I tried causing SEU’s (single event upsets) in SRAM, it just means causing errors, a 0 at a location on the chip flips to a 1 or vice versa its typically non destructive, the thing was though that I could not burrow down close enough to the silicone without damaging the chip to the point that it would not work at all. I am still looking for an Sram with the die exposed, I don’t think I am going to have any luck there though…..

Next I tried removing the lens from photodiodes to see if I could detect anything there, still working on that, the voltages are so low that noise becomes a big problem though. I looked at scintillators but thought getting the material might be tricky.

I then looked into ion chambers, you can make some nice low voltage ones that can be used as a pretty accurate measurement device, check out DIY ones here…

http://www.techlib.com/science/ion.html

because of capacitive effects of the wires you don’t get any nice blips like the G/M tubes just an over all measurement, but if that’s all you are after then fine.

I want to find a way of capturing discrete events or groups of events so the Ion chamber may not be the way to go for me.

I still think the Sram may be the way to go, the errors are nice and discrete and already in a digital form… yummy.

Any ideas anyone?