PERMANENT MAGNET ELECTROMAGNETIC LENS

摘要

PURPOSE:To stably operate a permanent magnet electromagnetic lens over a broad temperature range by moving the operating position with a temperature sensitive moving mechanism and temperature-compensating the diffraction effect of electronic beams. CONSTITUTION:The fixed tool 7 and the electromagnetic lens movable section 6 which are mounted on the vaccum tube 4 is connected by the temperature sensitive moving mechanism 8. This temperature sensitive moving mechanism 8 permits the electromagnetic lens movable section 6 to be positioned for the electron beams 5. For example, the temperature sensitive moving mechanism 8 is obtained by converting the temperature variation of temperature sensitive elements such as bimetals into the change of length or into rotary movement or moving the electromagnetic lens movable section 6 by the actuation of screws.