CLEARING METHOD FOR MATERIAL FOR ULTRAHIGH VACUUM

摘要

PURPOSE:To clear a material for ultrahigh vacuum and to enable the ultrahigh vacuum to be kept in the irradiation conditions of an electromagnetic wave or a corpuscular beam by irradiating an electron beam having proper eV on the material the ultrahigh vacuum while exhausting it in the high vacuum. CONSTITUTION:After decompressing practically the inside of a vacuum vessel 11 provided with a material for ultrahigh vacuum to be cleared with a roughing- down system 12, it is kept in the high vacuum with a high vacuum pump 13. Then an electron beam having several tens KeV - several MeV which is fed from a high-current electrostatic type electronic accelerator (not shown in a chart) joined via a pipe 14 is irradiated on the above-mentioned material 1. As the above-mentioned electrostatic accelerator, a Cockcroft-Walton accelerator or a Van de Graaff accelerator is suitable. Also a position of the above- mentioned material 1 for the electron beam is transferred with a position transfer mechanism 15 and it is preferable that the electron beam is uniformly irradiated thereon. Thereby the above-mentioned material 1 is cleared for a short time to dissociate the adsorbed molecule and enabled to keep ultrahigh vacuum.