I've finished printing the circuit board, it should be completed by this evening.

In the meantime, I made some progress on the source.

The Geiger tube is wrapped around the lead shielding with the radioactive source. I closed the ends by gluing lead strips around the edges, and used a lab NaI scint counter to check for leakage. Nothing seems to get out of it, we'll see in the long term how the shielding holds.

A small, self-contained source plus tube!