<title>Performance of the PACS photoconductor arrays aboard FIRST</title>

Abstract

For the instrument PACS (Photoconductor Array Camera and Spectrometer) aboard FIRST two photoconductor arrays dedicated for different wavelengths bands are foreseen in the spectrometer section. Each camera consists of 25 linear arrays of 16 stressed Ge:Ga crystals. The arrays with 2 X 400 pixels will be used for imaging line spectroscopy in the wavelengths ranges 60 micrometers to 110 micrometers and 110 micrometers to 210 micrometers . The detectors are read out by a new generation of integrating and multiplexing cryogenic read-out electronics, which is currently under redesign and further development. The development of the arrays has passed the engineering phase and entered the qualification status. We summarize the results obtained with the engineering arrays and the first 6 qualification models with respect to their performance such as uniformity of current sensitivity and cutoff wavelength. The impacts of the result of the first 6 linear arrays on the qualification model are described together with the final design which is supposed to fulfill the specifications and requirements of the instrument PACS.