Oak Ridge National Laboratory

Physics Division

Physics Division Seminars

Physics Division Seminars bring us speakers on a variety of physics related subjects. Usually these are held in the Building 6008 large Conference Room, at 3:00 pm on the chosen day, but times and locations may vary. For more information, contact our seminar chairman,

Alfredo Galindo-Uribarri
Tel (Office): (865) 574-6124  (FAX): (865) 574-1268

Tue., May 15, 2012, at 3:00 p.m. (refreshments at 2:40 p.m.)

Vacuum as High Voltage Insulation Does Anyone Really Understand It

William Diamond, AECL
Building 6008, Large Conference Room

The first X-ray tubes were invented more than 100 years ago, using vacuum as electrical insulation between electrodes at high voltage. It was soon observed that increasing the distance between electrodes did not enable an equal increase in voltage. This became known as the total voltage effect and it has limited the performance of many practical devices. After more than 100 years of research on vacuum-high-voltage insulation, progress remains slow and the basic problem is still not solved. The author has spend several extended periods of his career trying to understand that and several other complex problems associated with the use of vacuum as high voltage insulation. This talk will review some of that work with particular emphasis on desorption of large quantities of gas from the anode electrode as voltage is increased. The physics of this is complex and not well-understood and this effect is limiting progress on devices such as dc electron guns for Free-Electron Lasers and E x B optical elements.

Alfredo Galindo-Uribarri 574=6124