Engineering topics

Shannon, J. L.

Publications and source records attributed to Shannon, J. L..

4 records

NASA NTRS1985

Design and performance of the high-resolution spectrograph sensor subsystem

The general design and performance of a digicon sensor system developed for the high-resolution spectrograph (HRS) to be flown on the shuttle-launched space telescope are discussed. The digicon sensor system consists of an encapsulated digicon tube, deflection/tweaking coil, permanent magnet assembly, wiring interface assembly, preamplifiers, and high-voltage power supply. The performance attributes and capabilities of the digicon sensor system exceed those of any existing space qualified system; the HRS digicon lifetime has been demonstrated to be far in excess of space telescope orbital requirements.

Eck, H. J.↗

NASA NTRS1980

Tension-mode loading for bend specimens in cryogens

Special fixture permits use of tension-loading apparatus in fracture-toughness tests on standard bend specimens. Specimen is held in place by spacer blocks and wire clips. Central, load-application roller bends specimen between lateral, reaction-load rollers.

Pierce, W. S.↗

NASA NTRS1980

State-of-the-art Space Telescope Digicon performance data

The Digicon has been chosen as the detector for the High Resolution Spectrograph and the Faint Object Spectrograph of the Space Telescope. Both tubes are 512 channel, parallel-output devices and feature CsTe photocathodes on MgF2 faceplates. Using a computer-assisted test facility, the tubes have been characterized with respect to diode array performance, photocathode response (1100-9000 A), and imaging capability. Data are presented on diode dark current and capacitance distributions, pulse height resolution, photocathode quantum efficiency, uniformity and blemishes, dark count rate, distortion, resolution, and crosstalk.

Ginaven, R. O.↗

NASA NTRS1979

Space Telescope Digicon

The Digicon, chosen by NASA as the detector for the High Resolution Spectrograph (HRS) and the Faint Object Spectrograph (FOS) is a 512 parallel output channel vacuum photodetector. There are two HRS Digicons with spectral sensitivity ranges from 1050 A to 1800 A and 1150 A to 3000 A respectively, and two FOS Digicons, which have spectral ranges extending to 7000 A. The significant requirements for these devices are 0.01 counts per second background count rate per diode, state-of-the-art Digicon pulse height resolution (typical 15%) and a high degree of imaging precision and stability. The results of a manufacturing and test program to develop the Digicons coupled with extensive prior work has shown that these requirements can be met. The Digicon because of its inherent ruggedness is particularly well suited to space applications.

Alting-Mees, H. R.↗