• Saigonauticon@voltage.vn
    link
    fedilink
    English
    arrow-up
    9
    arrow-down
    1
    ·
    1 year ago

    Nice – you wouldn’t happen to have any ideas on how to differentiate positron annihilation, from the continuous distribution of β− energies caused by the more common decay mode, using only a PIN photodiode? I’m a bit stumped on this point and suspect it’s not possible. I probably need to do gamma spectroscopy but would really rather not.

      • Saigonauticon@voltage.vn
        link
        fedilink
        English
        arrow-up
        3
        ·
        1 year ago

        Yeah, that’s going to be too hard. I only have two SiPMs (besides the current detector) and they are expensive. I figured I could maybe rely on the gamma from the annihilation energy being a quite different energy than the gammas from the more common electron-capture.

        However you raise a good point that that would not be a very good demonstration of positron annihilation at all – just evidence that it’s not the other 2 decay modes (and it would take ages to collect that evidence besides). Ah well. Got plenty of other science I can do instead.

        Probably I’ll tackle something easier like checking for radon decay products in petrol.

          • Saigonauticon@voltage.vn
            link
            fedilink
            English
            arrow-up
            4
            ·
            1 year ago

            ‘Not too hard’ is a bit of a spectrum I guess ;)

            I mean yeah, in principle I could cram textbooks for a few months (I know EE and SE pretty well, but particle physics only very basic stuff), order parts made at the factories I know, and would probably succeed eventually. More realistically I’d have to hire a university prof as a consultant to save time.

            What I am really unable to construct is a powerpoint presentation that justifies that expense and labor to management :P

            Especially in a cost-driven market (my company is in Vietnam). Often the parts for these things are export-controlled too, that can be a real pain. I’ve gotten irate phone calls from the US DoD before over fairly innocent parts orders – it’s not super fun. I recall it was some generic diode, I must have stumbled on something with a military application I wasn’t aware of. The compliance paperwork ended up costing me hundreds of dollars for 20$ in parts, too.

            Anyway, if it was something I could just tack on to ongoing research projects, I could maybe get away with it as a marketing expense. It’s for a STEM program. It’s hard enough to convince management to take the risk on a nuclear & quantum module as-is! I can mostly get away with it because the locally-manufactured beta-detectors cost like 20$ per classroom.