eROSITA focal plane instrumentation design

The German X-ray instrument eROSITA (extended ROentgen Survey with an Imaging Telescope Array) is the main instrument of the new Spectrum-RG mission orbiting at L2. The launch of the Russian satellite is planned for the year 2012. The scientific goal of eROSITA is primarily an all sky survey with detection and analysis of 100 thousand clusters of galaxies in order to study the large scale structures in the Universe and to test cosmological models. The therefore required large effective area is obtained by an array of seven identical and parallel aligned Wolter-I telescopes. The focal plane instrumentation is realized with a 384 × 384 pixel frame store pnCCD mounted on a ceramic PCB and cooled to -80 C. The ceramic PCB also houses three CAMEX readout ASICs to amplify and filter each of the 384 channels in parallel. The cooled ceramic is connected via a flex lead to the electronics box at room temperature. A copper housing shields for proton radiation whereas a graded-Z shield attenuates X-ray fluorescence.