Engineering topics

Hier, R. G.

Publications and source records attributed to Hier, R. G..

4 records

NASA NTRS1989

Low temperature multi-alkali photocathode processing technique for sealed intensified CCD tubes

A low temperature photocathode process has been used to fabricate an intensified CCD visual photocathode image tube, by incorporating a thinned, backside-illumined CCD as the target anode of a digicon tube of Hubble Space Telescope (HST) design. The CCD digicon tube employs the HST's sodium bialkali photocathode and MgF2 substrate, thereby allowing a direct photocathode quantum efficiency comparison between photocathodes produced by the presently employed low temperature process and those of the conventional high temperature process. Attention is given to the processing chamber used, as well as the details of gas desorption and photocathode processing.

Doliber, D. L.↗

NASA NTRS1985

Investigation of CCD-digicon detector system characteristics

The reported investigation was undertaken with the aim to develop state-of-the-art detector technology for use in astronomical observations. Basic properties of the Digicon concept are to be extended to the two-dimensional capabilities of CCDs. The basic CCD-Digicon tube configuration utilizes a thinned, backside-illuminated CCD in place of the linear, discrete diode array at the back end of a windowed space telescope (ST) design Digicon tube. It is pointed out that the detector system built around the considered device promises to exhibit high photometric accuracy in combination with large numbers of uniform independent resolution elements. Potential applications include space astronomy missions with capability for observations extending into the extreme ultraviolet spectral region. Attention is given to continuing investigations into the characteristics of CCD response to backside photoelectron bombardment, taking into account the development of charge pulse centroiding readout techniques in combination with magnetic deflection substepping.

Hier, R. G.↗

NASA NTRS1984

A low noise infrared spot scanner for testing detector arrays

A low noise spot scanner has been built for use in testing the performance of infrared detector arrays for NASA's IR detector technology development program and the University of California's MICRO program. The scanner provides a convenient low noise detector test environment and a wide range of test conditions including versatile temperature control of the detector, ambient background, and blackbody source temperature and control of spot size, color, and brightness.

Puetter, R. C.↗

NASA NTRS1984

Calculation of resolution for a windowless charge coupled device (CCD)-Digicon

A new version of an intensified charge-coupled device (ICCD) system, which is based on the incorporation of a CsI mesh photocathode and a thinned backside-illuminated CCD into a Space Telescope design Digicon tube, is being developed for future use in space-based observations in the Extreme Ultraviolet waveband. In this paper, a report is presented of the results of computer simulations involving the effects of the non-uniform electrostatic field near the mesh photocathode on imaging properties (especially, the spread function and modulation transfer function) of the detector system. The results are of importance in the design of the front end of the tube and the selection of optimum tube operating conditions. The overall resolution characteristics of the tube, including the effects of the mesh, the electron optics of the region between the mesh photocathode and the CCD target, and the structure of the CCD itself, are estimated.

Jia, X. Z.↗