Hitachi S-4800 manual Column tab

2.3.8.1 Column tab

The Column tab is for setting operating condition of the electron optical column.

(1) HIGH MAG MODE block

Set column condition for High Mag mode.

(1-1) Probe current

Select Normal or High. For resolution prior operation, use Normal. In case where larger probe current is required, select High.

(1-2) Focus Mode

Select UHR or HR.

UHR mode is optimized for operation at short working distance. Full working distance range allowed for the present accelerating voltage can be used.

HR mode is for use of rather long working distance. Longer than about 5mm working distance is able to be focused.

(1-3) Cond Lens 1

The check box On or Off excitation of the 1st Condenser Lens.

Usually set it On (checked)

Select a excitation value with selection box. The range is 1.0 to 16.0. Higher number results stronger excitation and then small probe current. Usual recommendation value is 5.0.

For fine setting, use the up-down buttons. (1-4) Cond Lens 2

The check box On or Off excitation of the 2nd Condenser Lens. Usually set it On (checked)

(1-5) Focus Depth

Set ocus depth. Selectable range is 0.5 to 2.0. Resolution optimized condition is 1.0. To increase focus depth, select larger number.

For usual operation, set it to 1.0 or larger to increase focus depth. (1-6) Specimen Bias Voltage

Specimen Bias Voltage (-15V) is applied for optimum secondary electron detection. Set it to ON for normal operation. Turn it off for some special applications such as EBIC.

When operating the S-4800 at short working distance, you may end up with images of uneven brightness throughout the field at low magnifications. We suggest to set Specimen Bias Voltage at OFF in order to correct this problem.

When the specimen is tilted, however, the upper detector signal will decrease

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