Spectrometer, rocket borne

Rocketborne Field-Widened Interferometer-Spectrometer. The rocket-borne field-widened interferometer-spectrometer (RBFWI) is an example of an instrument that uses emission techniques to make broad-band spectral measurements in the 2 - 7.5 pm spectral region in the upper atmosphere. Figure 10 illustrates the concept of this cryogenically-cooled instrument developed at Utah State University under an Air Force Geophysics Laboratory contract. 

Atmospheric plasma research was originally stimulated by the interest in radio wave propagation and therefore was focussed on the ionosphere. Thus, the early in situ ion composition measurements were made in the ionosphere at altitudes above about 100 km using rocket-borne spectrometers [15, 16, 17]. Below 100 km, the atmospheric gas pressure becomes so large that mass spectrometers have to be pumped which represents a major barrier for extending in situ ion composition measurements downwards into the mesosphere. Such measurements became technically feasible only with the advent of compact high speed cryopumps which could be used on rockets. 

Upper atmosphere chemical processes have been mentioned above, and rocket-borne mass spectrometers have been used to investigate the various species—molecules, atoms and ions—present in the upper atmosphere. Bennett type RF mass spectrometers have been especially useful in view of their small weight compared with conventional magnet spectrometers. Johnson describes a typical mass spectrometer-rocket probe of the atmosphere. 

Rocket-borne Spectrometer for the Study of Dynamic Molecular Processes in the Atmosphere... 

Spectrometer 1 is based on a linear self-scanned image sensor, capable of providing a 10 ms per spectrum, scan time. This spectrometer was borne by the S-310-8 rocket, which was launched from Kagoshima Space Center (131°04 45"E, 31°15 00"N) at 17 47 JST (Japan Standard time, 135°E) on February 2, 1980. The spectrometer, that measured the NIR absorption of atmospheric constituents such as and H 0, was according to our knowledge the first rocket-borne multichannel spectrometer capable of measuring spectra with an altitude resolution better than 2 km. 

Figure 1. Schematic diagram of the rocket-borne NfR spectrometer. Key A, amplifier S/H, sample and hold A/DC, analog-to-digital converter D/A, digital-to-analog converter and ALU, arithmetical logic unit. (Reproduced with permission from Ref. 3. Copyright 1981, American Institute of Physics.)...

Figure 3. The time sequence of the rocket-borne spectrometer. (Reproduced with permission from Ref. 3. Copyright 1981, American Institute of Physics.)...

Figures, (a) A schematic diagram of the rocket-borne spectrometer designedfor measuring the rotational profile of the A-band absorption spectrum of O, molecules. Key II, image intensifier IS, photodiode array CG, clock generator CC, clock controller and PD, photodiode. (Reproduced with permission from Ref. II. Copyright 1983, American Geophysical Union.)...

The first detection of stratospheric positive ions by rocket borne mass spectrometer (Arnold et al., 1977) showed that above 45 km the most abundant ions were proton hydrates (H+- (H20)n) while below that altitude non-proton hydrates (NPH) of masses 29 2, 42 2, 60 2, and 80 2 were dominant. Arijs et al. (1978) also observed ions with a mass number of 96 2. 

Water cluster ions H (H20) were first detected in the earth s lower ionosphere in late 1963 with rocket-borne mass spectrometers by Narcisi and BaileyIt was found that the ion 37,H502 dominates the ion... 

Fehsenfeld and Ferguson and Good et independently suggested the type of mechanism that must be involved in the production of the proton hydrates. This mechanism and the rate constants measured by Good et al. were given in Table III (Section 4). The reactions and rate constants of Table III were used by Ferguson and Fehsenfeld for calculation of the rates and concentrations of proton hydrates in the ionosphere. With reasonable assumptions these authors were able to reproduce semiquantitatively the cluster concentration-altitude profiles observed with the rocket-borne mass spectrometers. The reaction scheme proposed by Ferguson does not explain the fate of the NO" ion. At mid-latitudes NO" ions are believed to be produced at a faster rate than 02", yet is observed only as a minor ion. In laboratory experiments, NO is converted to H (H20)3 by the reaction sequence... 

The k and the product ion distributions for such reactions are readily determined using the SIFT. Rocket-borne mass spectrometers have shown that NO+ ions are a major species in the upper TA, even though neutral NO does not exist in measurable concentrations. Flowing afterglow and SIFT experiments have shown that these ions result primarily from the ion-molecule reaction ... 

Our current understanding of the chemical nature of atmospheric ions and their role in atmospheric aerosol and trace gas processes derives primarily from in situ ion composition measurements using rocket-, balloon-, and aircraft-borne mass spectrometers [11, 12] as well as from laboratory studies of ion-molecule reactions and ion nucleation [13, 14]. 

Most recently, in 1984, detailed ion composition measurements could for the first time be performed in the stratopause region by our group [31], using a newly designed parachute-borne dropsonde mass spectrometer payload, which is carried by a rocket up to 60 km altitude and subsequently separated from the rocket motor. Positive and negative ion composition data could be obtained between about 30 and 60 km altitude. Thus, the gap between the regions covered by conventional rocket (above about 60 km) and balloon measurements (below 45-40 km) could be closed. 

Rocket- and Space-Borne Mass Spectrometer Measurements 288... 

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