Charge coupled devices (CCDs) as x-ray detectors for exotic atom spectroscopy

Full text: The status of CCDs as x-ray detectors for exotic atom spectroscopy is presented. CCDs have become standard x-ray detectors in the exotic atom field due to their background rejection capabilities, remarkable energy resolution and intrinsic pixel-size position resolution. The mediocre efficiency in a relatively small energy range and the minimal or absent timing information are being improved upon. Some of the ongoing experiments with CCDs are (I) precision measurement of the 2P - 1S line width in pionic hydrogen and pionic deuterium at PSI. Details on the CCDs used in this experiment can be found in literature. (II) Precision measurement of the charged pion mass at PSI. The present accuracy of 3 ppm will ultimately reach 1 ppm. (III) Kaonic nitrogen and kaonic hydrogen measurements at Frascati by the DEAR collaboration. Furthermore, a pn CCD has been developed and put into service successfully, which should solve the CCD efficiency and timing problems. (author)