JEOL JSM-IT200 Instructions Manual page 33

2.2.2 Objective lens aperture
2.2.2.a Standard (MAP1)
X and Y direction fine adjustment knobs used for adjusting the movable aperture.
The aperture foil is composed of two (25μm diameter and 50μm diameter), and it can be exchanged
according to the purpose of use.
X direction fine
adjustment knob
Aperture foil
（μm diameter）
It is mounted when sipping at the factory.
25
When a sharp image is required, such as for high-resolution observations (observations at
×10,000 or more)
When a high beam current is frequently used for observation and analysis in the low
vacuum mode.
50
The beam current will increase 4 times more than that of 25μm diameter with the same
P.C. setting.
INo.ISMIT200-1E
Table 2-1 Relationship between diameter and purpose of use
Purpose of use
Y-direction fine
adjustment knob
2-3