Characterisation Of Fully Depleted Pn-CCD's For X-Ray Imaging

Abstract

The second fabrication of fully depletable, backside illuminatable pn CCD's on high resistivity 280µm thick silicon (e ti 2.5 kSlcm) has been tested. Two dimensional X -ray imaging was performed; the multilinear arrangement of the pixel -rows (pixel size 100 x 54µm2) allows a fast readout of the entire detector. We present results of measurements concerning the static device characteristics (leakage currents) and their temperature dependance. Their contributions to the detector noise are calculated. Entrance window thicknesses for this kind of devices have been measured in two different ways. Quantum detection efficiencies in the energy range from 100eV to 10keV are derived and compared to first results obtained with synchrotron radiation in the spectral range between 500eV and 1900eV. An improved design using epitactical silicon with a more suitable geometry and an on -chip JFET electronics has been developed and is currently being fabricated. Further developed devices of this kind are proposed as focal plane instruments for one EPIC (European X -ray Photon Imaging Counter) on the XMM (X -ray Multi Mirror) mission.