Bredthauer, Richard | Engineering Papers

NASA NTRS1989

Development of large CCD arrays with enhanced UV performance

A development status evaluation is presented for proprietary UV-range CCDs for military and scientific applications requiring pixel sizes in the 18-micron range. The most recent developments in UV/X-ray responsive detectors have their bases in the backside illumination of multipinned phase (MPP) 1024 x 1024 CCD arrays, as well as in the initial exploration of open-pinned phase (OPP) techniques. The frontside performance of both MPP and OPP devices is noted to be excellent as well, and pinouts and mounting techniques have been defined which allow easy front-back operation comparisons. Novel backside processing techniques are being refined.

Varian, Richard H.↗

NASA NTRS1988

Fano-noise-limited CCDs

Recent developments of scientific CCDs have produced sensors that achieve ultra low read noise performance (less than 2 electrons rms) and near perfect charge transfer efficiency (0.9999996) without the addition of a fat-zero. This progress has now made it possible to achieve Fano-noise-limited performance in the soft X-ray where the detector's energy resolution is primarily limited by the statistical variation in the charge generated by the interacting X-ray photon. In this paper, Fano-noise-limited test data is presented for two different CCD types and a CCD derived estimate of the Fano factor is determined. By evaluating ultra low-modulation images (less than 1 electron peak-to-peak) it is shown that the CCD's global CTE is now superior to its read noise floor. To capitalize on this capability CCD manufacturers are now focusing their attention on reducing the noise floor below the 1 electron level thereby matching the sensor's CTE performance. This improvement, if accomplished, will push Fano-noise-limited performance for the CCD into the extreme ultra-violet.

Janesick, James↗