Deflection Unit and Power Control Unit for HP-4 RHEED Gun
HP-4 is
designed to deliver a high quality electron beam under realistic MBE conditions.
This is achieved by using several beam alignments that can be adjusted while
the gun is operating. The position of the electron beam source can be varied
to center the brightest spot of he filament on the optical axis.
The first set of deflection plates then eliminate any deviation in the beam direction. And finally, the aperture manipulator allows the exact alignment of the electron beam with the axis of the magnetic lens for minimum aberrations.
Selectable apertures reduce the beam diameter and divergence, while the electron source is operated at its optimum for minimum energy spread. This results in superior FWHM and transfer width of the diffraction pattern.
Electrostatic deflection is used throughout for maximum stability and minimum beam distortion. The internal electromagnetic shielding greatly reduce the influence of stray fields,the most important noise source in RHEED experiments.
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Electron energy 3...50 keV Electron energy stability
(± 0.01 %, ± 0.001 % optional)
(PDF)