Performance evaluation, readout modes, and calibration techniques of HgCdTe Hawaii-2RG mosaic arrays

Recently ESO has commissioned the HAWK-I camera which is equipped with a 2×2 mosaic of λc~ 2.5 µm HAWAII-2RG arrays. The arrays have high quantum efficiency and achieve photon shot noise limited performance on the telescope. Using reference pixels it can be shown that the readout noise for most arrays is limited by the MBE grown HgCdTe material and not by the multiplexer or the data acquisition chain. Results obtained with the guide window of the HAWAII-2RG multiplexer will be presented. Inter-channel crosstalk and fringing in the detector substrate will be discussed. The dynamic range of detectors can be expanded by applying threshold limited integration (TLI) to the follow-up-the-ramp nondestructive sampling scheme. For substrate removed arrays a calibration technique based on the X-ray emission of Fe55 will be discussed.