RADIAL VELOCITY SPECTROMETER: TECHNICAL ISSUES

摘要

We examine the main technical issues which constrain the Gaia-RVS scientific performance, and drive its design. These are the need to maximise the number of detected photons given the Spectra telescope size and fixed exposure durations, and to minimise the internal instrument noise. The resulting design combines an elegant high efficiency optics solution, with L3CCD detector technology on high resistivity Si material, to maximise the quantum efficiency and minimise the readout noise. To cope with the data rate from the instrument, data from individual CCDs are combined on board, after remapping onto a common spatial scale and removal of blemishes and cosmic rays, then compressed with a lossless algorithm, necessary for the preservation of the low level signals in the data.