Demagnifiers0 pages
DEMAGNIFIERS
nnnnPhotek
nnnnFEATURES
nnnn. 47, 80 or 150 mm input
nnnn• 6:1 zoom ratio
nnnn• Magnification from 0.1 to 0.6
nnnn• Gateable
nnnn• Distortion less than 5%
nnnn• Gen I high dynamic range
nnnnAPPLICATIONS INCLUDE
nnnn• X-ray imaging
nnnn• Beta autoradiography
nnnn• Dynamic X-ray TV
nnnn• Nuclear physics
nnnn• X-ray crystallography
nnnn• Non-destructive testing
nnnnINTRODUCTION
nnnnThe DM47, DM80 and DM150 are rugged metal-ceramic tubes with tetrode electrostatic focusing. Change
nnnnof magnification is accomplished by simultaneously adjusting the voltage on three electrodes.
nnnnThe photocathode is remotely processed in a vacuum transfer system, assuring high efficiency and low-
nnnnnoise. It is processed on a plano-concave fibre optic window, with a maximum useful diameter of 45, 76
nnnnor 140 mm.
nnnnThis range of demagnifying intensifier has no microchannel plate (MCP) - the photon gain is dependent
nnnnonly on operating voltage and the efficiency of the photocathode and phosphor screen.
nnnnCompared to a fibre optic taper, the electrostatic tube offers a photon gain of around 100 photons/
nnnnphotoelectron at 10 kV with P43 phosphor; sufficient to overcome readout noise of scientific CCDs without
nnnndegrading dynamic range or resolution, which is typically less than 20 microns at the output surface.
nnnnThe design gives a small amount of pin cushion distortion, which is almost zero at mid-range
nnnnmagnification and the construction minimises sheer distortion and blemishes.
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