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7.5 Format-Dependent Sensitivity
The sensitivity of the FOC depends on the format being used. The overall (OTA + COSTAR + FOC) central absolute quantum efficiency Q(
) in counts photon-1 (DQE), plotted in Figure 4.3 and tabulated as a function of wavelength in Table 11 of the FOC Instrument Handbook (version 7.0), refers to the 512 x 512 format. Because the DQE is a function of detector format whose cause is unknown (see FOC ISR 075), we give in Table 7.3 the sensitivities of the other formats, relative to the 512 x 512 format. Typical uncertainties in these numbers are approximately 5%.
The pre-COSTAR overall (OTA + FOC) central absolute quantum efficiency Q()
in counts photon-1 (DQE) with no filters in the beam is plotted and tabulated as a
function of wavelength in Figure 28 and Table 12 of the FOC Instrument Handbook, version 3.0, for the FOC imaging and spectrographic configurations. The
data represent the product of in-orbit measurements for the f/96 camera and
ground-based measurements of the f/48 absolute quantum efficiency, reflectance
measurements of the OTA primary and secondary mirrors witness samples and an
arbitrary dust covering factor of 10%. Pre-COSTAR data are not automatically
corrected for format-dependent sensitivity effects.
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Last updated: 11/13/97 16:44:29