Mark E. Fraser

Midcourse Space Experiment (MSX): plans and capability for the measurement of infrared earthlimb and terrestrial backgrounds

A major objective of the MSX program is to obtain global data of atmospheric and terrestrial backgrounds simultaneously in the infrared (2.6 to 28 micrometers ) and short wave (0.11 to 0.9 micrometers ) spectral regions. This paper presents an overview of the plans and capabilities to measure infrared earthlimb and terrestrial backgrounds with the cryogenic infrared MSX sensor, the spatial Infrared Imaging Telescope (SPIRIT) III sensor. Of particular importance is the characterization of the spatial-temporal structure and the global distribution of mean radiometric levels and spectral content of both quiescent atmospheric and terrestrial backgrounds as well as the backgrounds associated with aurora, mesospheric and noctilucent clouds, stratospheric warmings, wave phenomena, scatter and thermal emissions from clouds, terrain, and other sources. Experiments are planned to collect data as a function of latitude, season, diurnal conditions, magnetic activity and altitude, up to tangent heights of 300 km over a period of 18 months for the infrared (cryogen lifetime) and 5 years for the visible and ultraviolet sensors. Coordinated experiments are planned with ground sites and in conjunction with other satellites. Automated processing will provide rapid data reduction and the generation of data products.

Rovibrational excitation of carbon monoxide by energy transfer from metastable nitrogen

The CO fundamental vibration–rotation spectra resulting from the interaction of discharged nitrogen with carbon monoxide at low pressure (∼3 mTorr) exhibit bimodal rotational distributions. We have identified 14 vibrational levels of a rotationally relaxed (80 K) component and eight vibrational levels from a rotationally excited component. The eight rotationally excited bands are best reproduced by a statistical distribution E=ER+EV=3.7 eV, which provides sufficient population in the region of the Fortrat reversal (J∼90) to account for the observed R‐branch bandhead formation. The rotationally relaxed vibrational levels are populated by single‐ and two‐quantum transfer from N2(v), N2(v)+CO→N2(v−1,2)+CO(v=1,2), and radiative cascade from CO(A) produced by quenching of N2(a’), N2(a’ 1Σ−u) +CO→N2(X,v)+CO(A 1Π)→CO(v≤9)+hν, and relaxation of the rotationally excited component. Kinetic and energetic arguments indicate that a branch of N2(a’) quenching N2(a’ 1Σ−u) +CO→N2(X,v)+CO(v≤14,J) is responsible for the ro...

Infrared emission from the electron irradiated upper atmosphere produced by the Excede: Spectral experiment

This paper presents the results and interpretation of infrared data obtained by the Excede:Spectral auroral simulation experiment. The authors have analyzed 2- to 7-{mu}m data from the two circular variable filter spectrometers. The dominant N{sub 2} electronic transition system identified in the data across this region is the N{sub 2}(W{sup 3}{delta}{sub u}{nu} {le} 5 {yields} B{sup 3}II{sub g},{nu} {le} 3) band system which is observed at all altitudes. Nitric oxide fundamental emission is observed in the 5- to 7-{mu}m region. The determined NO vibrational distribution can be attributed to the reaction N({sup 2}D) + O{sub 2}.

Real time monitoring of airborne metals

Potential human exposure to airborne metals occurs in a broad number of government and civilian operations and processes. Included among these are hard chromium plating, firing ranges, metallurgy and metals processing, lead paint abatement, and decontamination and decommissioning activities at hazardous waste sites. Effective control of these fugitive emissions requires sensitive real time monitoring. Physical Sciences Inc. (PSI) has developed a real time monitor for lead and chromium based on spark-induced breakdown spectroscopy (SIBS). The basis of SIBS is a high energy breakdown creating atomic emission which is sensitively viewed with a radiometer. This technology has been successfully demonstrated to detect low ppbw ((mu) g/m3) concentrations of lead and chromium in incinerator stack gases (joint DoE/EPA test a Research Triangle Park in September 1997), airborne lead at a local firing range (in the airspace of the shooters and in the ventilation system), and chromium at a hard chromium electroplating facility. The PSI SIBS technology is being developed as an inexpensive real time monitor for toxic metals in a variety of applications including: process control, emission compliance and industrial hygiene. Our progress towards developing a commercially viable prototype will be reviewed.

Portable sensor for hazardous waste

Objective was to develop a field-portable monitor for sensitive hazardous waste detection using active nitrogen energy transfer (ANET) excitation of atomic and molecular fluorescence (active nitrogen is made in a dielectric-barrier discharge in nitrogen). It should provide rapid field screening of hazardous waste sites to map areas of greatest contamination. Results indicate that ANET is very sensitive for monitoring heavy metals (Hg, Se) and hydrocarbons; furthermore, chlorinated hydrocarbons can be distinguished from nonchlorinated ones. Sensitivity is at ppB levels for sampling in air. ANET appears ideal for on-line monitoring of toxic heavy metal levels at building sites, hazardous waste land fills, in combustor flues, and of chlorinated hydrocarbon levels at building sites and hazardous waste dumps.