waht,Just wondering if there are any commercial radiation detectors that already utilize these diodes? According to google, avalanche diodes were developed quite recently.
waht,Some of those germanium detectors need to be cooled with liquid nitrogen, so I'm not sure if this is possible (off the shelf).
Beside the cost of PMT, the electronics to interface a PMT is very simple. I'm EE major. But I guess the low level photons we're dealing with is going to be an issue.The energy resolution of a Ge(Li) or HPGE detector won't help him with cosmic rays and scintillator, as everything he's looking at is minimum ionizing anyway. This isn't worth the expense.
I assume that the OP wants to avoid PMTs because of cost. I'm afraid that this will be hard to do. A tube is a few hundred dollars, but it's probably $2000 for a setup. You need a tube, and a preamp, and an amplifier-shaper-discriminator, and a HV source for the tube, and a LV source for the preamp, and all this adds up. (The cost for a second tube, of course, is smaller, since several of these components can be shared) Replace the tube by an APD or a silicon PMT, and you still need all the periphery. Different actual components, to be sure - for example the voltage requirements are different - but the total system cost for a one channel system is not grossly different.
Understand you are looking at very, very low levels of light here. Perhaps a hundred photons.
Indeed, detecting muons with Ge xtals is pretty silly (and expensive). What you need is a relatively large detection volume, and you don't need precise detection, so I would opt for a gas detector. No need to go through scintillation. A big tube with a wire in it under HV, and you don't need much. You will need the gas filling (and hence access to a vacuum pump and such) and a tight container. But then for a simple Geiger tube, you don't even need much electronics (a HV power supply, some resistors, a HV capacitor and then a speaker or a pulse counter).The energy resolution of a Ge(Li) or HPGE detector won't help him with cosmic rays and scintillator, as everything he's looking at is minimum ionizing anyway. This isn't worth the expense.
How did you interface the fiber to a scintillation crystal?I built photon counting geiger mode APD units 10years as a grad student for about $500.
They had a fibre pigtailed APD from EG+G Canda that was about $250 at the time, a little single stage peltier cooler to get the APD down to 250k and some circuitry that quenched the diode, and output TTL pulses- it counted photons upto about 3Mhz. The unit was about the size of an altoids tin.
I didn't - these were for astronomy.How did you interface the fiber to a scintillation crystal?
I think I saw such a paddle in fermilab, but it was coupled with a PMT whose surface area of contact was many times bigger than that of a fiber. I'm going to do more research on APDs.I didn't - these were for astronomy.
I haven't worked with particle physics detectors, but the ones I have seen are large (1m long) complicated curved bits of plastic that end in an output face a couple of cm square.
You could couple that into a fibre fairly easily. The fibres that came with these diodes were 200-250um multimode (don't remember the NA).
I really just meant that APDs are very easy to work with compared to PMTs.
That's the advantage of PMTs of course.I think I saw such a paddle in fermilab, but it was coupled with a PMT whose surface area of contact was many times bigger than that of a fiber.