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

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.