SEARCH · Search NASA
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Development of time of flight mass spectrometer using laser powered vaporization source is discussed. Operation of equipment to measure thermal velocities of individual mass species is described. Illustration of test equipment installation and detailed line drawing of ion producing equipment are provided.
A balloon-borne photoionization mass spectrometer used to measure stratospheric trace gases is described. Ions are created with photons from high-intensity krypton discharge lamps and a quadrupole mass analyzer is employed for ion identification. Differential pumping is achieved with liquid helium cryopumping. To insure measurement of unperturbed stratospheric air, the entire system is contained in a sealed gondola and the atmospheric sample is taken some distance away during descent. The photoionization technique allows the detection of a low ionization potential constituent, such as nitric oxide, at less than a part in one billion in the presence of the major atmospheric gases and their isotopes. Operation of the mass spectrometer system was demonstrated during a daytime flight from Palestine, Texas on 26 April 1977. The sensitivity achieved and the unique selectivity afforded by this technique offer a capability for trace constituent measurement not possible with the more conventional electron impact ionization approach.
The use of lasers as a source of excitation for surface mass spectroscopy has been investigated for some time. Since the laser can be focused to a small spot with intensity, it can vaporize and accelerate atoms of material. Using this phenomenon with a time-of-flight mass spectrometer allows a surface elemental mass analysis of a small region with each laser pulse. While the technique has been well developed for Earth applications, space applications are less developed. NASA Langley recently began a research program to investigate the use of a laser to create ions from the lunar surface and to analyze the ions at an orbiting spacecraft. A multijoule, Q-switched Nd:YAG laser would be focused to a small spot on the lunar surface, creating a dense plasma. This plasma would eject high-energy ions, as well as neutrals, electrons, and photons. An experiment is being set up to determine the characteristics of such a laser mass spectrometer at long flight distances. This experiment will determine the character of a future flight instrument for lunar resource assessment.
Explore the source record for details and available documents.
The purpose of this test report is to summarize results from the vibration testing of the INFICON Transpector MPH100M model Mass Spectrometer. It also identifies requirements satisfied, and procedures used in the test. As a payload of Resource Prospector, it is necessary to determine the survivability of the mass spectrometer to proto-qualification level random vibration. Changes in sensitivity of the mass spectrometer can be interpreted as a change in alignment of the instrument. The results of this test will be used to determine any necessary design changes as the team moves forward with flight design.
A special gas inlet system is required for reduction of high ambient pressures to ion source operating pressures for mass spectrometer investigations in the stratosphere for the determination of the abundance of minor constituents. A system has been designed which combines a mass spectrometer and a gas inlet system reducing pressure by differential pumping using high-speed liquid helium pumps and small orifices. The gas particles are formed into a neutral beam with a flag mechanism proceeding into the mass spectrometer ion source where they are ionized for subsequent mass separation. A laboratory model has been tested under conditions simulating stratospheric pressures. It was shown that the process is able to identify gases with abundances below 10 to the -8th. Some of the problems associated with gas analysis of trace constituents have been alleviated, and other applications of the system have been identified, such as pollution control and medicine.
A comparison of satellite mass spectrometer data from Dynamics Explorer-2 and Atmosphere Explorer-C and -D provides new evidence supporting the hypothesis that NO2 is the source of the observed continuum glow near ram-facing surfaces of the Space Shuttle. Surface reactions of thermospheric N and O in mass spectrometer ion sources produce NO and NO2 in amounts highly dependent on surface temperature and composition, with direct exposure of ion source surfaces to rammed gas a necessary condition for the production of large amounts of NO2. Initial orbit data indicate that a period of surface conditioning is necessary before these odd nitrogen molecules can be produced efficiently.
A focusing equation is developed describing the relationship between space and velocity focusing for all one-dimensional time-of-flight mass spectrometers with constant electric fields. As a result of this equation, first-order double time focusing in one dimension is impossible. The possibility of large improvements in the resolving power of the time-of-flight mass spectrometers is discussed on this basis. The focusing equation also leads to an expression for the minimum time resolution obtainable. This second equation is applied to the conventional Wiley and McLaren (1955) two-field time-of-flight mass spectrometer with and without time-lag focusing, and to the mirror instrument of Karataev et al. (1972).
Double-focusing mass spectrometer for quantitative atmospheric particle measurements by orbiting satellite
A time-of-flight mass spectrometer (TOFMS) is described in which the single flight tube of a conventional TOFMS has been replaced by several cylindrical electrostatic lenses in tandem. By a judicious choice of voltages on these lenses, an improved TOFMS has been realized which has a superior mass and energy resolution, shorter flight lengths, excellent signal-to-noise ratio, and less stringent requirements on the bias voltages.
An ion mass spectrometer having a cylindrical E bar x B bar analyzer and either a cylindrical or spherical electrostatic analyzer is described. The instrument has two nested channels and a postacceleration between the electrostatic and E bar x B bar analyzers for wide ranges of energy and mass responses. It is noted that the dual-channel construction not only doubles the data acquisition rate but also permits a reversal of the electrostatic field orientation in the inner channel for lighter ions. The outer channel is then optimized for ions of medium to high mass numbers, resulting in increased mass resolution for such heavy ions. When combined with a cylindrical E bar x B bar analyzer, a 90-deg-deflection angle spherical electrostatic analyzer provides an extremely wide viewing angle. The angular distribution of ions can be derived from such geometry if a position-sensitive resistive anode or a detector array is used at the exit aperture. Details on the principles of operation, the instrument design, and calibration are presented.
Operating parameters of omegatron mass spectrometer in ultrahigh vacuum determined for helium, nitrogen, argon, and carbon dioxide to give maximum sensitivity
The experiment to measure the composition and distribution of the ambient lunar atmosphere by mass spectrometer is reported. The lunar orbital mass spectrometer is described along with the calibration procedures for the instrument. Preliminary results indicate that a large number of gas molecules were observed in the vicinity of the spacecraft in lunar orbit. Many of these molecules are considered to be of spacecraft origin.
Mass spectrometer data acquisition and analysis using digital computer
Construction of cold cathode quadrupole mass spectrometer as flight prototype
Proposed dual column gas chromatographic mass spectrometer for analyzing Jupiter atmosphere
The gas chromatograph-mass spectrometer instrument to be utilized in the Viking 1975 Molecular Analysis experiment has undergone preliminary testing in its flight configured version. A synthetic mixture of 24 components as well as a sample of the Murchison meteorite has been used for this purpose. The resulting data not only allowed the identification of most of the organic compounds known to be present, but also revealed the identity of a few unexpected ones. Thus, the sensitivity and reliability of the instrument and data system are satisfactorily demonstrated.
Microprocessor controlled mass spectrometer data acquisition system simultaneously monitors up to nine gaseous products emitted from heated substrate during thermal desorption experiments.