The electron bean which has the sectional diameter of angstrom order and the high brightness is necessary to obtain an ultrahigh resolution in the field of electron microscopy, electron spectroscopy and other electron beam technology, and the field emitter called tip is suitable for this purpose. We have already published that we can make small protrusions near (100) planes on the tungsten tip apex by field evaporation at about 600 K.Concerning the treatment of the tip called remolding we reported with my coworker, august 1974 at the eighth international congress on electron microscopy in Canberra Australia. The LaB6 field emitter has recently received considerable attention as an electron beam source of higher brightness as well as longer life time than conventional tungsten field emitter. LaB6 cathode has been used as such a cathode because of high thermal stability and stable for poisoning gas. However, the surface state of this cathode at high temperatures during operation has been scarcely known, because there has not been effective method to analyse the surface materials or to observe the surface condition.
Design of a high brightness multi-electron-beam source
