Improved X-ray CCD Response at Very Low X-ray Energies

摘要

We report laboratory measurements of the response of a back-illuminated, X-ray photon-counting charge-coupled device at X-ray energies between 80 and 500 eV. The detector tested, which is similar to one currently in orbit aboard the Suzaku X-ray Imaging Spectrometer, has been treated with the chemisorption charging process developed by Lesser and colleagues. We report energy scale linearity and spectral resolution measurements in this energy band, which spans the silicon L_(Ⅱ,Ⅲ) absorption edge, and demonstrate useful spectral resolution at energies as low as 83 eV with our single-read-per-pixel system. We discuss the factors currently limiting device performance and briefly consider the challenges of exploiting this capability in future astronomical instruments.