SCAN-TYPE ELECTRON MICROSCOPE

PURPOSE:To invariably perform an analysis in an extremely high vacuum by providing a detector in a sample chamber, providing an ion gun in a sample exchange chamber, providing means to change the ion outgoing direction in the ample chamber and sample exchange chamber, and providing a variable valve between the sample chamber and sample exchange chamber. CONSTITUTION:A sample exchange chamber 15 is provided adjacently to a sample chamber 10, which is discharged through a discharge pipe 11, and the exchange chamber 15 is discharged by a separate exhaust pump through a discharge pipe 16. The sample chamber 10 and exchange chamber 15 are connected by a variable-conductance valve 12, and a sample 5'' supported by a support tool 19 can be shifted to the analysis position 5' in the sample chamber 10 by means of an exchange bar 17 and a knob 18. An ion gun 20 is fitted to part of the wall of the exchange chamber 15 through a shift mechanism 21 and is shifted to the sample 5'' side to radiate an ion beam 8'' to the sample 5'' when cleaning the sample 5''. When analyzing a sample 5', the ion gun 20 is shifted by the mechanism 21 to radiate in the direction of a beam 8. At this time, only a slight opening 14 is formed, and the analysis can be performed by maintaining the extremely high vacuum of the sample chamber 10.