Filter
Top Products
3.10 Image Quality
3 - 158
3.10.2 Probe Current Setting and Image Quality
On the ELECTORION BEAM block, image quality can be adjusted by specifying an appropriate
probe current level. An appropriate setting should be selected in reference to the table below.
The default probe current is set to 50. The lower the probe current, the higher the resolution at
the expense of decreased probe current. For low-magnification observation, the probe current
should be set high, and for high-magnification observation, it should be set low.
Table 3.10-2 Probe Current and Image Quality
Probe Current Setting
Irradiation current
（A）
Low High
Resolution
High Low
Secondary electron signal
Low High
Image roughness
High Low
Charge-up
※1
Low High
※1: For non-conducting specimens
See 3.4.1 Setting Parameters for the Electron Optical System.
3.10.3 Objective Lens Movable Aperture and Image Quality
The diameter of the objective lens movable aperture can be selected from four options. The
table below shows the relationship between aperture diameters on one hand and the specimen
current, the focal depth, and applications, on the other hand. Resolution is set so that it is the
highest when the hole diameter is 30 µm. The probe current can be adjusted by using the
Probe Current menu on the Electron BEAM block.
The surface condition of the objective lens movable aperture can have a significant impact on
image quality, especially at low accelerating voltage levels. Maintenance services on the
objective lens movable aperture should be performed periodically. Also critical is axial
alignment for the electron optical system.
0 50 100