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FemtoLEED Spectrometer DLD L800

Nano-Scale Measurements of Surface Periodic Structures with Femto-Ampere Electron Probe

Collaboration with RoentDek in Germany.

The FemtoLEED with integral shutter enables nano-scale measurements of surface periodic structures with a femto-ampere electron probe. Instead of a fluorescent screen, it uses a delay line detector and allows for fully digital operation.


  • Primary electron beam in the range of femto ampere
  • Electron diffraction on insulating single crystal samples
  • Large coherence width
  • Powerful operation with digital LEED controller


With its primary electron beam in the range of femto ampere, the FemtoLEED DLD L800 is specifically useful for investigations on sensitive organic samples. The fully digital system negates the need for an external CCD camera for live image capture.


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

Side view of FemtoLEED DLD L800.
Front view of FemtoLEED DLD L800.

Key Specifications

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

Detector Delay Line Detector with dynamic range 32 bit per channel, 75 microns spatial resolution and active area 145x145mm
Acceptance angle 77 °C angle of acceptance from sample
Retarding Field Analyser Concentric assembly of hemispherical grids
Working distance 15mm from sample
Grid material Gold coated tungsten wire mesh (100 mesh, 81% transparency)
Energy Resolution 0.2%
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 a 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
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 107, operating in pulsed mode

Configuration Guide

The FemtoLEED DLD L800 optics is controlled using a LPS075-D power supply with a MCPS02 controller used to operate the microchannel plates. Integral shutter (Model ISH-8) and LaB6 filament (Model LaB6) are further options.

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