Features: Electron Optics System Electron gun The type of electron gun: ★(1)FEG (Field Emission Gun ) ★(2)W filament(Tungsten
filament gun ) Tungsten filament gun works ★3 pole hair fork-tungsten cathode electron gun ★Self-bias, bias resistor adjustable
★Added to between the gate and the anode , a continuously adjustable from 0 to 30KV negative high voltage ★providing a tiny
high-brightness electron source and obtaining a stable high-brightness beam. ★Mechanical alignment system Electromagnetic beam
alignment system Condenser lens Objectives lens ★Lens is used to focus images ,its Structure is a more specific .It accommodates
scanning coil and elimination astigmatism component,to effectively reduce the sample's surface magnetic field ;aperture is on the
top of lower pole shoes,so that beam spot size down to focus on the minimum size of the sample . The vertical distance from lower
pole shoes to sample surface is called the working distance -WD ★Requires a long working distance, a low spherical aberration
coefficient and a small magnetic flux leakage. Eliminate astigmatism ★As the processing error, or a winding core in the
non-uniform magnetic field asymmetry which can damage the magnetic lens symmetry ,so that it makes an oval beam spot into a spot
instead of the standard round spot .It is called astigmatism . ★Eliminate astigmatism correction is used to provide a weak field
on the image astigmatic correction. ★Eliminate astigmatism in the scanning device mounted inside the coil components. ★There are
X, Y pairs of images in both directions for a more positive astigmatism. Scanning coils ★Using X, Y two directions of magnetic
deflection coil. Electron beam scans the sample was raster-like .That is, X direction of scan (line scan) and the Y direction of
scan (frame scanning). ★SEM was taken point by point imaging method , Tube of the electron beam scanning and display the scanning
electron beam is strictly synchronous ,therefore, the image on the display screen is a enlarging image scanned on the sample area
. ★Magnification of scanned images is determined by the current flowing through the coil, the larger the current, the greater the
angle of scan, then the lower image magnification. In a given scan angle, the working distance increases, the lower magnification.
Specimen chamber ★The specimen chamber installed in the vibration-isolation frame, Electro-optical tube installed in the top of
the specimen chamber, Vacuum system is installed below the specimen chamber. ★Specimen stage from the front door into the specimen
chamber, specimen chamber deflation does not affect the vacuum tube. ★Chamber provides a large space, but also to annex to install
convenience. ★Specimen stage is so large enough range of movement that it can be used to observe a large specimen. ★Specimen stage
to carry out a five-dimensional movement: X, Y, Z, rotation, tilt, etc. ★Specimen stage has sufficient machining accuracy to
achieve micron-level mobile. Signal reception processing and display system ★Electronic signal from the specimen out through the
grid into the detection system. When the grid added +300 V, it can effectively collect low-energy secondary electrons, when the
grid added-100V voltage, collecting less than a secondary electron. However, due to higher energy backscattered electrons are
still part of the direct scintillator was collected. So when the grid with 300V, the read secondary electron image. When the grid
add-100V, the probe can be observed backscattered electron image. ★10KV high voltage conductive layer increases, the purpose is to
improve the detection efficiency. Accelerated the secondary electrons hit scintillator to generate photoelectron, The
photoelectron through the tube to the photomultiplier tube ,Photomultiplier tubes transform light signals into electrical signals
,Via pre-amplifier , a weak electrical signal will be amplified and sent to video amplifier, Then the output sent to the image on
the imaging system. ★Image output mode: Monitors to observe or photograph. Magnification ★When the incident electron beam to
raster scan ,If the electron beam scans the specimen surface, the magnitude of As, In the cathode-ray screen simultaneously scan
amplitude Ac, The SEM magnification as follows: M=Ac/As ★Resolution ★SEM resolution is the main performance index. In terms of
micro-area composition analysis, it refers to sub Analysis of the minimum zone; Right image, it is the means to distinguish
between a minimum distances between two points. Resolution size is determined by the incident electron beam diameter and the type
of joint decision-modulated signal. Electron beam diameter, the smaller the higher the resolution. However, the physical signal
for the imaging is different, For example, secondary electron and backscattered electron, in the launch of the scope of the
specimen surface is not the same, thus affecting its resolution. General secondary electron image resolution is about 5-10nm,
backscattered electron image resolution of about 50-200nm. Computer and software systems ★It is a part of the electrical control.
★Automation and intelligence is an important characteristic of modern instruments. ★Make the operation of electronic microscope
convenient. ★To achieve office network and automation. Vacuum system ★Provide vacuum which electro-optical system requirements
★Vacuum systems include: Mechanical vacuum pumps and high vacuum pumps, vacuum 3.alves, vacuum vibration-isolation, vacuum
measurement, Etc.
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Business Type: Manufacturer
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