A novel photometric approach for the measurement of terrestrial dayglow emissions

Conference · Sat Dec 31 04:00:00 EST 1994

OSTI ID:227950

Swift, W R; Torr, D G ^[1]

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1. Univ. of Alabama, Huntsville, AL (United States)

Ground-based observations of terrestrial dayglow emissions requires the measurement of a small signal embedded in a large background. The authors report the development of an instrument to accomplish this. Under sky background dominated conditions, the signal to noise ratio achievable for the measurement of an airglow line feature with a filter photometer depends little on the filter bandwidth. Thus, apart from spectral purity considerations, the only value of using a smaller bandwidth is that it reduces the number of counts needed to obtain the same statistical S/N. Critical design aspects include the development of the detector techniques needed to count very large photon fluxes generated by the bright daytime sky, and to maintain very high relative stability between the sky background and the dayglow feature channels. High counting rates are achieved by operating in analog mode using high bulk resistivity, low noise silicon diodes in an electrometer integrator circuit. High stability is achieved by using high resistivity dual diodes on a single silicon wafer, and locating the electronics in the same controlled environment. The authors demonstrate the use of such a filter photometer by the measurement of the diurnal variation of the 630 nm (red line) dayglow emission.

• OSTI ID: 227950
• Report Number(s): CONF-940723--; ISBN 0-8194-1590-1
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
AIRGLOW
CHEMICAL COMPOSITION
DESIGN
DYNAMICS
EMISSION SPECTRA
IONOSPHERE
MEASURING INSTRUMENTS
PHOTOMETERS
PHOTOMETRY
SIGNAL-TO-NOISE RATIO
TEMPERATURE MEASUREMENT