
The device I designed just before PMU (not the device above) was a cylindrical metal-ceramic electron tube the size of a 5 inch long crucifix with a copper rod down its center. A high electric current (about 200 amps) flowing in the rod generated a magnetic field. The electron tube was mounted or jury-rigged on a frame. At the heart of the assembly was a one-half inch diameter by one inch long cylindrical tantalum cathode heated to 3100 deg F. Its intense white light emanated from the openings between the plates of the electron tube and I was aware of its rays as I waited for it to heat up or as I worked around it, studying for countless hours how it operated. This could be done since in its vacuum phase it was enclosed by a highly evacuated glass bell jar and in its cesium phase by a metal bell jar with a quartz window. I was not aware at the time that the electron tube was in the form of a crucifix, but what joy I felt to see it work.