at once, but is quite workable.

The maximum row-gap gives an integration time for the entire frame of about 1.7 seconds (see Table 1). Generally, such integration cannot be done at high gain because the CMOS pixels will saturate almost instantly with most sources. Therefore, a lower gain on the MCP is used in order to reduce the signal level by a factor 10 or more, and therefore allows multiple photons events to fall on one location on the CMOS without saturating the pixel wells. True dark-current then becomes a problem. Dark-current is typically highly dependent upon temperature, but the expected temperature averages of the detector in orbit are expected to be similar to those in the laboratory, typically around 20$^o$C. These measurements were therefore taken in order to examine some typical dark-current characteristics. Table 1 shows the dark current from the three channels for different integrate times. The current is not uniform across the detectors, so we show the range and mean, smoothed over 10 pixels. Table 2 shows the photon-counting read rates for different window sizes.

Flat fields
===========

Flat fields were measured using a UV-reflective integrating sphere. The exit aperture of the sphere was 3 inches (significantly 