US 4,085,327 A · Direct charge readout electron radiography apparatus with improved signal-to-noise ratio

Abstract

An improved direct charge readout electron radiography apparatus of the type having an upper electrode receiving differentially-absorbed X-radiation, a lower electrode including a plurality of parallel transparent, conductive strips overlaid with a layer of photoconductive material; and means for scanning a beam of light through the transparent strips and into the overlying photoconductive material layer for selectively transferring charge patterns induced therein responsive to the pattern of differentially-absorbed X-radiation, utilizes at least one lead means strip, positioned substantially transverse to, and spaced from the ends of, the plurality of conductive strips. The transverse lead means strip is connected to sequential ones of the parallel strips responsive to illumination of the photoconductive material in the area between the transverse strip and an adjacent end of each sequential parallel strip. The reduction in device capacitance in parallel with a device output signal, facilitates an increase of about 100 times in the amount of readable charge, for equal exposures. Apparatus for optically scanning each conductive strip; while maintaining the connection thereof to the transverse lead means, is also disclosed.

Claims39

Dependent claims

An improved direct charge readout electron radiography apparatus of the type having first electrode means receiving differentially-absorbed radiation, means for receiving the radiation passing through said first electrode for converting said radiation to a pattern of charged particles, second electrode means spaced from said first electrode means beyond said converting means for receiving said pattern of charged particles and means for reading the image of charged particles from said second electrode, wherein the improvement comprises said second electrode means including:

a plurality of substantially parallel elongated strips of a transparent and conductive material, each strip having a first end;
lead means spaced from said first end of each of said plurality of strips;
first means overlaying at least said plurality of strips for storing said charge image until receipt of a first radiation stimulus;
and
a plurality of second means for electrically connecting only an associated one of said plurality of strips to said lead means, each of said second means separately responsive to receipt of a second radiation stimulus.

2 more elements

a plurality of substantially parallel elongated strips of a conductive material, each strip having a first end;
lead means spaced from said first end of each of said plurality of strips;
first means overlaying at least said plurality of strips for storing said charge image until receipt of a first radiation stimulus;
a plurality of second means for electrically connecting only an associated one of said plurality of strips to said lead means, each of said second means separately responsive to receipt of a second radiation stimulus;
a plurality of substantially parallel mesh strips, each strip being positioned between a pair of adjacent ones of said first electrode means than said conductive strips;
and
said mesh strps being adapted to be held at a first potential relative to the conductive strips to facilitate collection of charge in those regions of said first means closest to said first electrode means and essentially only over said mesh strips.

4 more elements

Dependencies are inferred from the claim text.

Direct charge readout electron radiography apparatus with improved signal-to-noise ratio

Life of this patent

Direct charge readout electron radiography apparatus with improved signal-to-noise ratio

Life of this patent

Abstract

Claims39