Add Photomultiplier tubes support

[vikulin]

As I have already mentioned here #66 Photomultiplier tubes support would be greatly increase possible reproducibility. Especially for such kind of scintillation radiometers such as СРП-68, СРП-88. There are ton of such detectors laying in peoples storages from USSR time.

[NuclearPhoenixx]

Technically any input device is supported as long as the input voltage range is about 0 to 1.1 Volts max. In that case the preamp will not clip the signal and if the rising edge is not extremely fast as well, it should work just fine.

Please let me know what would qualify as "PMT support" in your opinion.

[vikulin]

Technically any input device is supported as long as the input voltage range is about 0 to 1.1 Volts max. In that case the preamp will not clip the signal and if the rising edge is not extremely fast as well, it should work just fine.

Please let me know what would qualify as "PMT support" in your opinion.

PMTs require higher voltage vs SiPMs. Typical range is between 750-2000V and with very low current. Diode voltage multiplier does the job. Necessary rate 5Vx100x1.5 (x10 for a transformer, x10 for diode cascades). Also it require higher input impedance for pre-amp. I see 1k input resistor but should be 50k. I have already created main PCB and working on power supply schema for high voltage. I will send the PR in a separate Git branch containing a specific model of Photomultiplier tube.

[NuclearPhoenixx]

OK, sure but how would these changes allow for compatability for both SiPMs and PMTs? You can't just simply increase the input resistor and the power supply would have to be able to provide a clean low-noise 30V too. Or am I mistaken and you want to create an alternative version for PMTs only?

[vikulin]

OK, sure but how would these changes allow for compatability for both SiPMs and PMTs? You can't just simply increase the input resistor and the power supply would have to be able to provide a clean low-noise 30V too. Or am I mistaken and you want to create an alternative version for PMTs only?

Power supply feeds a PM tube only. Rest of schema would be identical except the input resistances pairing. Of course I consider PMTs only for that version.

[NuclearPhoenixx]

Okay, sounds good. In that case, I think it would be actually better for you to have your own fork and maintain the PMT side of things, and I'm happy to link you in the README here if people are looking for PMT support. Because I'd not be able to take good care of it since I have yet to build and test myself a PMT setup (lol). Let me know what you think!

[vikulin]

Okay, sounds good. In that case, I think it would be actually better for you to have your own fork and maintain the PMT side of things, and I'm happy to link you in the README here if people are looking for PMT support. Because I'd not be able to take good care of it since I have yet to build and test myself a PMT setup (lol). Let me know what you think!

I suggest to hold the code in one place rather then to split it into two projects. I could maintain the separate branch which would correspond to PMT implementation. Sending PRs/MRs would be much easier across different branches in one project. Otherwise I will create a fork but you would need to fetch my git branches list manually because I'm going to separate SiPM and PMT support across different branches as I have already mentioned above. Let me know which variant works for you.

[NuclearPhoenixx]

Hm, I get your point. However, since I can't test it and wouldn't be of any help at all in the time being, I wouldn't love to have that in here "officially", honestly. I get tons of emails (mostly hw/sw "support" questions) that I would have to turn down or forward so this isn't really a suitable solution for me.

Maybe we can compromise and you create a repo with the new hardware only and I keep maintaining the software here? Did you need any modifications on the software for the PMT support?

[vikulin]

Hm, I get your point. However, since I can't test it and wouldn't be of any help at all in the time being, I wouldn't love to have that in here "officially", honestly. I get tons of emails (mostly hw/sw "support" questions) that I would have to turn down or forward so this isn't really a suitable solution for me.

Maybe we can compromise and you create a repo with the new hardware only and I keep maintaining the software here? Did you need any modifications on the software for the PMT support?

No, the software looks good enough. I would move the software code to a separate git module. As result every new hardware project could link it as a submodule. Also I would add CI/CD job in GitHub actions to publish a firmware once new update/release done.