[URSpider94]

I didn't look at his bio, but I assumed that he must do something in the field in his day job -- it would be really hard to stockpile this much knowledge from scratch, even with the help of the Internet ...

Nonetheless, he did this with the gamma spectrometer in his spare room ...

[wycx]

Note that a high purity Germanium detector requires LN cooling to operate, and judging by the size of the dewar on his detector, would need filling maybe once a week to keep it cool all the time.

That is a bit onerous if you only play with it every now and then and don't have a 20000 L LN tank in your backyard.