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LEED 800 MCP (model BDL800IR-MCP)

Organic Films & Molecular Beam Epitaxy

Description

The LEED 800 MCP with integral shutter has LEED and AES capabilities using a miniature electron gun, set of concentric grids and a conductive, phosphor coated screen. In addition, this optic model incorporates the high gain of microchannel plates. It is an extremely reliable high-performance LEED instrument which operates with up to date digital power supply. The retraction mechanism has outstanding mechanical properties ensuring smooth day-to-day operation as experienced by our large user base over decades. The wide viewing angle (101° at 75mm sample distance) and minimal shadowing of the screen by the miniature electron gun give a maximum visible LEED pattern.


Features

  • High Image Sensitivity at the Primary Beam Current – 50 pA
  • Single/Dual 75 mm Microchannel Plates
  • AES at Beam Current 50 µA – 10 µA
  • Large Angle (101°) Fluorescent LEED Display and superior magnetic shielding
  • Miniature electron gun with large coherence width and dual lenses
  • Suitable for ESDIAD
  • Convenient LEED Image Capture with External CCD Camera
  • Simple and Powerful Operation with Digital Controller

Applications

The LEED 800 MCP is especially good at providing LEED and AES data of organic samples. The larger size allows for higher angular and energy resolution and the gain from the MCPs allows better focusing of LEED imaging.

Drawings

For seamless integration, 3D step files are available for all models.

Layout of LEED 800 MCP (model BDL800IR-MCP) optic.

LEED 800 MCP (model BDL800IR-MCP) calculation formula for Flange-Sample distance & Retraction length:
FS = 165.5mm + 2 LMX – OV; where FS is the flange to sample distance, LMX is the retraction length and OV is the overlapping length.

Rear view of LEED 800 MCP (model BDL800IR-MCP) optic.
Front view of LEED 800 MCP (model BDL800IR-MCP) optic.
Side view of LEED 800 MCP (model BDL800IR-MCP) optic.

Key Specifications

For detailed specifications, download LEED 800 MCP Configuration and Specifications (PDF).

Optics
Glass-display  Fused silica coated with indium-tin oxide conductive layer and P31 phosphor (ZnS:Ag:Cu-green, 525 nm wavelength)
Acceptance angle 101 °C angle of acceptance from sample at a distance of 75mm
Retarding Field Analyser Concentric assembly of hemispherical grids
Working distance 20mm from sample
Grid material Gold coated tungsten wire mesh (100 mesh, 81% transparency)
Energy Resolution 0.2% - 0.5% at low modulation voltages
Monitoring 8" standard viewport
Linear motion up to 100mm retraction from sample; linear ball bearing and acme thread with all spring electr. connections
Integral Shutter Manual shutter driven by rotary feedthrough
Magnetic shielding Mu-metal cylinder with front cover for maximum attenuation
Assembly Extreme-high-vacuum compatibility with stainless steel, high alumina and Au-plated copper alloy materials
Mounting 8"(CF150) double sided conflat flange with sample distance 145mm – 400mm
Bakeability Under vacuum, 250 °C maximum
Integral Miniature Electron Gun
Beam energy system LEED – 5 eV to 750 eV, AES – 5 eV to 3000eV
Beam current LEED – 2 µA at 100 eV and 0.5mm beam size, AES - up to 100 µA at 3 keV
Beam size from 1mm to 250 µm - adjusted by Wehnelt potential, limited by exchangeable aperture down to 50 µm
Electron source Tungsten-2% thoriated filament standard, 
single crystal LaB6 filament optional
Energy spread 0.45 eV (thoriated - tungsten filament)
Overall size 10mm lens diameter and 80mm length
Microchannel Plates
Working area 75mm
L/D ratio 40:1
Channel diameter 25 microns
Center to center spacing 32 microns
Plate thickness 1.0mm
Bias angle 8 °
Electron gain 104 to 105 per plate

Configuration Guide

The LEED 800 MCP optics is controlled using either a LPS075-D or LPS300-D power supply. The LPS075-D is used to operate the optic in LEED mode only whereas the LPS300-D in conjunction with the LOA10-AES lock-in controller and AUS30 input coupler is used to operate the optics in LEED and AES modes. Integral shutter (model ISH-8) and LaB6 filament (model LaB6) are further options. The MCPS01/02 controllers are used for operation of the microchannel plates.

For more information, download LEED 800 MCP Configuration and Specifications (PDF).

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