Last night I bombarded the fattest tube I have ever pumped. At 100mm diameter, 3mm wall thickness and about 5 feet long, its big.
This one is #borosilicate so I had a boro worker shrink it down and make the seals on a glass lathe.
Bombarding this is tricky, as the 19mm electrode glass is only 1.5 mm thick and will heat up more rapidly than the diffuse arc in the larger, thicker tube. To aid in the process, I wrapped the thick tube in the carcinogenic (but oh so insulative) frax blanket- which helped keep the heat in the middle like a jacket while the exposed #electrode extremities could cool down in between blasts from the bombarder.
I started with sorta normal pressures and currents (about 450ma current at about 5 torr of air) and then eventually ramped up to bombarding with about 1100ma of current at up to 17 torr of pressure! The outside took awhile to cool off and #vacuum out.
Gosh I wanna make one with xenon!
