Abstract: A CCD structure (20) tolerant to the adverse formation of traps resulting from exposure to irradiation by particles such as protons and neutrons is described. The CCD comprises an image plane (22) having a number of parallel transfer channels. Path defining structures (24), such as barrier implants, define a principal electron flow path through the channel, and define a number of secondary paths which converge on the principal path. The paths ensure that signal charge generated across the entire width of the channel is collected together into regions of smaller area so that the likelihood of interaction with traps is reduced, and charge containment is maintained near the optimum for all signal levels up to the full well.

Abstract: A solid state imager arrangement includes an image area, an output register which receives signal charge from the image area, a separate multiplication register into which signal charge from the output register is transferred, means for obtaining signal charge multiplication by transferring the charge through a sufficiently high field in elements of the multiplication register, and an additional register into which excess signal charge is transferred.

Abstract: A charge division arrangement for a CCD device for producing a divided charge output from an input charge, comprising an input for receiving an input charge, an array of elements and an output. The array of elements being arranged in rows and columns and having clock connections to allow charge in each row to be successively clocked from one row of elements to the next. At least some of the elements being arranged in a charge division unit having a first element and a second element in adjacent columns and being communicable at least temporarily so that charged introduced into the first element is divided between the first element and the second element, the charge division unit being arranged to produce divided charge for production at the output. The arrangement allows a small amount of charge to be introduced into a CCD circuit.

Abstract: A solid state imager arrangement includes an image area, an output register which receives signal charge from the image area, a separate multiplication register into which signal charge from the output register is transferred, means for obtaining signal charge multiplication by transferring the charge through a sufficiently high field in elements of the multiplication register, and an additional register into which excess signal charge is transferred.

Abstract: In an imaging apparatus particularly for use in intra-oral dental applications, a solid state imager is arranged to detect X-ray radiation from a source after passing through an object. Prior to irradiation by the source, charge accumulated in the elements of a CCD is clocked from two or more rows into a register such that charges are summed. The register is output via a charge amplifier which sums the charge applied to it to give a relatively large output signal which is amplified and applied to thresholder. Onset of X-ray irradiation is detected when the signal applied to the thresholder exceeds a reference level. A start signal is then transmitted to a control unit to cause image acquisition to begin.

Abstract: The input surface of a photocathode consisting of a membrane of p-type silicon is modified to improve it's sensitivity. The p-type concentration is locally increased and the surface is coated with silicon nitride.

Abstract: An electron-emissive semiconductor device such as a photocathode or an electron multiplier, consists of separate regions of semiconductor material spaced apart by a barrier which reduces current flow between the regions. The barriers improve the performance of the device by preventing excess electron emission currents and reduce image spreading.