The swept charge device, a novel CCD-based EDX detector: first results

The first results from a novel MOS-CCD-based EDX detector are presented. The device has been fabricated on high-resistivity epitaxial silicon and uses a novel pixel geometry to simplify operation over more conventional CCDs and possesses high sensitivity, high rate and high resolution for EDX applications. The charge is continuously clocked towards a single read-out at the corner of the 1 cm2 detector, with no spatial information retained and the device is functionally equivalent to a linear CCD in operation. Because of this sweeping action we have termed the device the “Swept Charge Detector”. The device uses a biased substrate which allows it to be operated in an extremely low-leakage current mode and results are presented at temperatures ranging from −35°C to room temperature. It can be operated in a photon-counting mode with pixel-by-pixel reset for optimum resolution or a reset-on-demand mode for optimum through-put. Its characteristics are compared to other types of silicon X-ray detectors.