The Photodetector Array Camera and Spectrometer (PACS) on the Herschel Space Observatory


Abstract in English

The Photodetector Array Camera and Spectrometer (PACS) is one of the three science instruments on ESAs far infrared and submillimetre observatory. It employs two Ge:Ga photoconductor arrays (stressed and unstressed) with 16x25 pixels, each, and two filled silicon bolometer arrays with 16x32 and 32x64 pixels, respectively, to perform integral-field spectroscopy and imaging photometry in the 60-210mu m wavelength regime. In photometry mode, it simultaneously images two bands, 60-85mu m or 85-125mum and 125-210mu m, over a field of view of ~1.75x3.5, with close to Nyquist beam sampling in each band. In spectroscopy mode, it images a field of 47x47, resolved into 5x5 pixels, with an instantaneous spectral coverage of ~1500km/s and a spectral resolution of ~175km/s. We summarise the design of the instrument, describe observing modes, calibration, and data analysis methods, and present our current assessment of the in-orbit performance of the instrument based on the Performance Verification tests. PACS is fully operational, and the achieved performance is close to or better than the pre-launch predictions.

Download