Characteristics around oxygen and silicon K absorption edges of a charge-coupled-device

We measure various spectral response characteristics around the oxygen and silicon K absorption edges of a Charge-Coupled-Devise (CCD) X-ray detector used in the X-ray Imaging Spectrometer (XIS) developed for the ASTRO-E mission. We have evaluated X-ray Absorption Fine Structure (XAFS) around oxygen K edge in detail. A strong absorption peak of 45% is confirmed just above the oxygen Kedge and an oscillatory structure follows whose amplitude decreases from 20% at the edge to less than 1% at 0.9 keV. We also show XAFS and discuss on a change of the response function around the silicon K edge. The discontinuity of the signal pulse height at the silicon K edge is less than 1.8 eV. We determine the thickness of silicon, silicon dioxide, and silicon nitride in the dead layer using the depth of the absorption edge.