LEED 800 MCP
LEED for Organic Films & Molecular Beam Epitaxy
- 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 double focusing
- Suitable for ESDIAD
- Convenient LEED Image Capture with External CCD Camera
- Simple and Powerful Operation with Digital Controller
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 75 mm sample distance) and minimal shadowing of the screen by the miniature electron gun give a maximum visible LEED pattern.
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.
For seamless integration, 3D step files are available for all models.
LMX length calculation for LEED 800 MCP (model BDL800IR-MCP):
FS = 158 mm + 2LMX – OV + WD; where FS is the flange to sample distance, LMX is the retraction distance, OV is the overlapping distance, WD is the working distance and the 158 mm value is a constant related to this optic model.
If the calculated FS value is longer than the actual port length a nipple adapter can be added as a spacer between the LEED optics and the UHV chamber. The nipple length can be calculated as follows:
NL = FS – PL; where NL is nipple length and PL is port length.
Configuration Guide and Specifications
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.
Fused silica coated with indium-tin oxide conductive layer and P31 phosphor (ZnS:Ag:Cu-green, 525 nm wavelength)
101° angle of acceptance from sample at a distance of 75 mm
Concentric assembly of hemispherical grids
20 mm from sample
Gold coated tungsten wire mesh (100 mesh, 81 % transparency)
0.2 % - 0.5 % at low modulation voltages
8" standard viewport
Up to 100 mm retraction from sample; linear ball bearing and acme thread with all spring electr. connections
Manual shutter driven by rotary feedthrough
Mu-metal cylinder with front cover for maximum attenuation
Extreme-high-vacuum compatibility with stainless steel, high alumina and Au-plated copper alloy materials
8"(CF150) double sided conflat flange with sample distance 145 mm – 400 mm
Under vacuum, 250 °C maximum
LEED – 2 µA at 100 eV and 0.5 mm beam size, AES - up to 100 µA at 3 keV
From 1 mm to 250 µm - adjusted by Wehnelt potential, limited by exchangeable aperture down to 50 µm
Tungsten-2 % thoriated filament standard,
single crystal LaB6 filament optional
0.45 eV (thoriated - tungsten filament)
10 mm lens diameter and 80 mm length