Sharp EL-6490 Bedienungsanleitung PDF herunterladen (Seite 18)

The electron optics column is designed to maintain high vacuum

during operation so that frequency of maintenance is kept low.

The objective lens aperture foil is easy to remove and to replace

precisely.

The orifice placed in the objective lens for differential pumping in

the low vacuum SEM is easy to remove for maintenance.

Factory

pre-centered

filament

Wehnelt

Replacement of the objective lens apertures

Turbo Molecular Pump (TMP) (Optional)

Easy to Maintain Electron Optics

It is important to center the filament tip to the small aperture on the

gun Wehnelt to ensure the best performance. JEOL provides facto-

ry pre-centered filaments, which are centered by JEOL. A user

does not have to center a filament. The proper heating of filament

and alignment of electron probe are automatically done.

JSM-6490 series SEM uses the high performance and reliable dif-

fusion pump (DP). With the DP it is necessary to heat the heater for

approximately 25 minutes before the DP is fully operational. The

DP also requires cooling water so that an SEM with a DP is not

convenient for moving.

An air-cooled TMP is available as an option for a user who wants to

use the SEM immediately after turning it on or to change the layout

of the laboratory frequently.

The vacuum system is completely identical except TMP being used

in place of DP. The TMP is not exposed to the air during specimen

exchange. The inside of the SEM is kept in vacuum while the SEM

is turned off.

The specimen chamber of the low vacuum SEM is pumped by the

dedicated rotary pump while the high vacuum region is pumped by

the TMP.

VV1

VV5

VV7

VV3

VV2

R. P1

R. P2

TMP

VV6

Electron gun

Objective lens

aperture

Backscattered

electron

detector

Orifice

(Needle valve)

controller

Pirani

gauge

Motor

drive

Foreline trap

High Performance is Maintained with Minimum Effort

Orifice (JSM-6490LA/JSM-6490LV)

Factory Pre-centered Filament

Optics with High Speed Pumping

Objective Lens Apertures

TMP Improves Mobility

Factory pre-centered

filament

Wehnelt

Evacuation system of Low Vacuum

SEM equipped with TMP

Objective lens

aperture

Low vacuum region

High vacuum region

Energy Saving

The entire electronics is enclosed in the main console to save

materials. The SEM is compact for easy installation. The power to

run the SEM is approximately 1.4kVA, which is quite small for the

high performance SEM.

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