Figure 2.13 shows the parameters for the SUR data collection technique. This is how science exposures (peak-up imaging and spectroscopic exposures) were read. Following an initial series of bias boost and reset frames, each pixel was sampled. The total time required to sample each pixel in the array is the frame time. There may be spin frames in which each pixel was accessed but not sampled. Every time the pixel was sampled, the data from each sample were saved and stored as an image to be sent to the ground for processing. Each IRS SUR mode exposure generated N 128x128 16-bit images, where N is the number of commanded sample frames. Note that some combinations of clocking patterns and frame times were inefficient or otherwise undesirable; hence, only a subset of all possible combinations was available to observers.
Table 2.3 lists the number of samples (Nsamples) used in SUR data collection mode for each available IRS integration time (tint). The corresponding time interval between samples () is found by dividing the integration time by the number of samples less one [tint /(Nsamples-1)]. The times given in the table are shorthand for the effective exposure times given in parentheses.
Figure 2.13: “Sample-Up-the-Ramp” data collection technique.
Table 2.3 SUR data collection mode sampling parameters.
) is found by dividing the integration time by the number of samples less one [tint /(Nsamples-1)]. The times given in the table are shorthand for the effective exposure times given in parentheses. 
