A TECHNIQUE TO MEASURE TRAP CHARACTERISTICS IN CCDS USING X-RAYS

An important type of radiation damage in CCD's used for X-ray spectroscopy is the degradation of charge transfer efficiency (CTE), Traps associated with radiation-induced defects are the basic cause of the damage. Here, we describe a method to extract trap characteristics using small charge packets produced by individual X-ray photon interactions in rectangular imaging CCD's. The method applies the principles of trap occupancy to the framestore CCD configuration, and uses data from CCD's operating in their normal transfer mode, We have measured trap characteristics in radiation damaged CCD's in a range of operating temperatures from 170-200 K, and have found that these data compare well to the expected phosphorus-vacancy CP-V) trap characteristics.