I was a research assistant on this project by Gerald Eilenberg at the University of Washington Physics Department. The thesis paper fully outlined the design of the entire system including capacitive power supply used to place a high energy charge on the internal plates. Different inert and nobel gasses were used . And how high sensitivity photo dectectors were used to pulse the power supply and operate high speed 35mm cameras.
If my memory is correct, ours was built inside a 10,000 gauss electromagnet.