Two multi-anode microchannel array (MAMA) detectors were fabricated at Ball Aerospace Technology Corporation for the Space Telescope Imaging Spectrograph (STIS) which was installed into the Hubble Space Telescope in February 1997. The photometric stability of the opaque CsI and semi- transparent Cs2Te sealed MAMA tubes has been characterized as a function of operating voltage and illumination conditions. A total exposure of 5 by 107 counts per pixel results in < 1 percent change in the detection quantum efficiency (DQE), which is attributed to conditioning of the microchannel plate (MCP) during tube processing. Employing good engineering practices to power supply design mitigates the effects of these components in long term detector stability. Other factors contributing to the photometric stability include the use of a curved channel MCP, photocathode processing, hydrocarbon free ultra high vacuum processing and sealed tube processing techniques. Contributions to the low resolution mode DQE stability are discussed along with empirical results on high resolution mode stability.
This paper will describe in some detail tow new large area CCD image sensors designed specifically to be used either as a single imager or assembled in mosaics of CCDs. The devices have 2048 X 4096, 15 micrometers pixels; the difference being the orientation of the serial register. Performance data are presented on both front- and back-illuminated parts. In addition, a new production camera test system will also be described which is being used to screen test the Advanced Camera CCDs for the wide field and high resolution channels.