DIY Geiger Counter

[Tech_Junkie]

I got up at 4AM. My sleeping schedule is always messed up. I only sleep a few hours at a time because of pain, so there is no regularity. Sometimes I'm up for days.

 

[lasersbee]

That sucks.....

I'm in the shop between 5 and 6 every morning... I don't
even need an alarm clock...


Jerry

 

[Tech_Junkie]

I started to drink to help, and it did, but I stopped before I started getting back into old habits.

 

[HIMNL9]

Maybe low energy ?

I remember i've read, long times ago, on a datasheet (can't find it again, sorry), something similar was made using a "fast rectifier diode" that was polarized inversely with a relatively high voltage (around 90V, for a 150V rated diode), so the particle can create detectable spikes crossing the junction ..... that unit was relatively high sensitive for the junction area, but, being the size of the junction really small (compared with a common ionization chamber), it was difficult to find "average" (or "medium distribution", if you prefer) radiations, like ambient ones , where instead was discretely efficent for build "localizer" detector units.

 

[Olly]

Well, I have put all the components together but I dont think its working or it is just not sensitive enough. Ive got a couple of CS/S on the old geiger counter, but nothing on the home made one I must of assembled it wrong

 

[Benm]

The small detecting area will be a problem with using either a photodiode or even a normale diode abused for this purpose. A radioactive source may not have a problem hitting an ionization chamber on a normal geiger counter, but it could completly miss the active area of the diode.

 

[ryahp]

I think it is like Benm has mentioned before: you need a scintillating material that will produce light from ionizing radiation. He mentioned scintillating liquids, but a scintillating plastic like some polystyrene doped with something like anthracene and a wavelength shifting fluorescent will be much more convenient to handle. And of course you must shut out any other light.

 

[grenadier]

Photodiodes and solar cells are terrible at detecting radiation, so don't expect to get any useful data out of this circuit. Personally I wouldn't rely on it for safety either.

There are a few special photodiodes that are designed for picking up x-rays, but these are quite expensive, and still crap compared to mica windowed GM tubes.

 

[HIMNL9]

Also, about scintillation crystals, have you never dismantled one of them ? ..... the crystal cartridge is usually big (like, 5cm dia x 5cm lenght, or similar), and after that there's not a photodiode detector, there's a photomultiplier tube (or in some cases, a crystals and tubes array) ..... very low sensitivity, if only a small crystal and a photodiode is used.

 

[grenadier]

No, there are actual photodiodes meant for x-ray detection! http://sales.hamamatsu.com/en/products/solid-state-division/si-photodiode-series/x-ray-detector.php

 

[HIMNL9]

LOL ..... sorry, i know well Hamamatsu, and overall their prices .....

some years ago i needed a flash lamp that can work at 250 Hz range, and there was only hamamatsu that was commercializing them ..... so, i asked them how much they cost for a sampling, and they replied me, "no problem, we can sold you a sampling for a minimum of 500 pieces, $300 a piece, 3 weeks for the delivery" ..... yeah, 500 pieces samples

I don't dare to ask them the prices of these photodiodes