Geiger telescope is designed and built:

This detector was a part of an art installation by Peter Chamberlain. The audio output drove an analog synth, creating video and sound based on the cosmic rays! Pretty neat.

I would really like to build another version of this design with the tubes mounted on a slip ring. With a help of a motor and an angular encoder I would be able to make a much finer $$cos(\theta_{azimuth})$$ measurement. But for now I need a break from Mr Geiger. I did start working on a detector which uses SIPMT, and that is keeping the physics side of my mind quite busy. Maybe I will write about that one....