Demagnifiers0 pages

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DEMAGNIFIERS

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Photek

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FEATURES

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. 47, 80 or 150 mm input

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• 6:1 zoom ratio

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• Magnification from 0.1 to 0.6

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• Gateable

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• Distortion less than 5%

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• Gen I high dynamic range

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APPLICATIONS INCLUDE

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• X-ray imaging

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• Beta autoradiography

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• Dynamic X-ray TV

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• Nuclear physics

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• X-ray crystallography

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• Non-destructive testing

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INTRODUCTION

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The DM47, DM80 and DM150 are rugged metal-ceramic tubes with tetrode electrostatic focusing. Change

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of magnification is accomplished by simultaneously adjusting the voltage on three electrodes.

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The photocathode is remotely processed in a vacuum transfer system, assuring high efficiency and low-

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noise. It is processed on a plano-concave fibre optic window, with a maximum useful diameter of 45, 76

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or 140 mm.

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This range of demagnifying intensifier has no microchannel plate (MCP) - the photon gain is dependent

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only on operating voltage and the efficiency of the photocathode and phosphor screen.

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Compared to a fibre optic taper, the electrostatic tube offers a photon gain of around 100 photons/

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photoelectron at 10 kV with P43 phosphor; sufficient to overcome readout noise of scientific CCDs without

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degrading dynamic range or resolution, which is typically less than 20 microns at the output surface.

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The design gives a small amount of pin cushion distortion, which is almost zero at mid-range

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magnification and the construction minimises sheer distortion and blemishes.

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