电子轰击加热六硼化镧阴极实验测量*

electron bombardment heating method capable of heating LaB6 cathode to 1559℃ has been developed. A LaB6 disk of size φ5.00mm×1.00mm has been heated to1559℃, with 49.2W and 251 W/cm2 of bombardment heating power. The temperature difference between center and edge is less than10℃. At 1551℃emissive current density is 3.5A/cm2.1.6×10-4Pa even lower air pressure is requested for a long life of the cathode.The electron beam bombards pyrolytic graphite clamper , no tungsten filament is coated by evaporated LaB6 and as a result bombarding power is stable. LaB6 did not crack under repeated heat strike.The cathode is dismountable , longevity and can be applied to powerful microwave tube. A phenomenon that the LaB6 surface color becomes grey has been observed in the experiment as the temperature rises,and this change is reversible.