Gamma Spectrometry Forum

Hello hello!

There is an old Picker nuclear scintillator probe that's been laying around in our lab for a while now but it has some weird connectors that I'm not sure what to do with. I've already tried to find documentation on it but it has little to no identifying markings and all the picker stuff is basically gone at this point being a long gone company. It has a 4 pin XLR connector on it in addition to a separate SHV connector. I've already tried connecting the thing with just the SHV but no signal comes out unsurprisingly, so I assume the signal is decoupled and sent through the XLR. But then why would one of these need 4 pins? Before I started buying a ton of adapters and wiring it up I wanted to check and see if anyone has some insight on this.

So the connector coming off of it looks like this: Bonus x-ray that I took of the detector, it's kind of cool to see the crystal and PMT like this:

The extra pins may be used to power an onboard pulse signal amplification circuit.

Oh, I didn't know that was a thing! That would make sense, would you have any idea what kind of voltage needs to be applied to operate typical pre-amps? I'm pretty ignorant on that stuff so I'm just trying to figure out a ballpark estimate. I do still have the old machine that it was most likely connected to so if need be, I might be able to power it back up and probe the pins but I have no idea if it still works or how to use it.

I've never encountered this particular probe, nor a probe with that specific connector, but I have seen other detectors with an SHV + 4-pin connector. I think the ones I've seen were mostly LEMO 1S-304 connectors which have a keyed 2 pins + 2 sockets layout. I've seen a couple of variations on that that theme - generally for detectors using BF3 or He-3 neutron detector tubes, but I think one might have been a scintillator. For those connectors, 2 of the pins are indeed signal, and the other 2 are the preamp power as Tom surmised. However, the variations I've seen included a few different power supply voltages. I think I've seen 5V, 9V and 12V on different systems.

jneilson wrote: ↑

05 Jun 2024, 04:58

I think I've seen 5V, 9V and 12V on different systems.

Thanks, to be honest I haven't had a chance to play around with it since the original post. I'm a bit scared to try wiring it up as I really don't want to fry anything, so if I do try it, I might start with the lower end of those voltages and see how it responds if I can get a response at all. Not sure when or even if I'll get a chance to try though. I'll post an update if I make progress.