  HxRG detectors have crosstalk between amplifier channels at a scientifically
relevant level. In principle, crosstalk signals can be fully calibrated and
removed from data, but only if a full crosstalk matrix is measured for the
detector. We present a fast method of crosstalk characterization that can be
performed with most instrument calibration units; it requires only a flat-field
illumination and window programming in the HxRG detectors. We show the
crosstalk matrices obtained with this method for both fast and slow mode in an
H2RG detector, and give examples of how this data can be used to tune detector
operation parameters, feed back into the electronics design for the cryogenic
pre-amplifiers, and be used in the data pipeline to remove crosstalk signal
from scientific data.
