Engineering topics
Publications and source records attributed to Giffin, C. E..
Proposed instrument makes rapid mass-spectrometric analyses of individual particles in aerosols. Each particle vaporized and ionized by intense laser pulse, which creates ions of minimum complexity. Ability to analyze single aerosol particles continuously makes technique suitable for detection of toxic aerosol particles on real-time basis and for identification of their sources.
Recent developments in the field of mass spectrometry taking place at the Caltech Jet Propulsion Laboratory are highlighted. The pertinent research and development is aimed at producing an ultrahigh sensitivity mass spectrograph for both spaceflight and terrestrial applications. The unique aspect of the JPL developed technology is an integrating focal plane ion detector that obviates the need for spectral scanning since all ions over a wide mass range are monitored simultaneously. The ion detector utilizes electro-optical technology and is therefore referred to as an Electro-Optical Ion Detector (EOID). A technical description of the JPL MS/EOID, some of the current applications, and its potential benefits for internal contamination analysis are discussed.
Online spectrometer monitors composition of individual aerosol particles. Single aerosol particles up to about 5 microns in diameter are analyzed for chemical composition, yielding valuable information on nature of pollution source. Tests show system has promise for monitoring oxidation of sulfur dioxide to sulfates important in controlling pollution from coal-fired power plants.
A description is presented of an instrument which was developed with the original goal of being flown on the International Comet Mission, scheduled for a 1985 launch. The Scanning Electron Microscope and Particle Analyzer (SEMPA) electron miniprobe is a miniaturized electrostatically focused electron microscope and energy dispersive X-ray analyzer for in-flight analysis of comet dust particles. It was designed to be flown on board a comet rendezvous spacecraft. Other potential applications are related to asteroid rendezvous and planetary lander missions. According to the development objectives, SEMPA miniprobe is to have the capability for imaging and elemental analysis of particles in the size range of 0.25 microns and larger.
Eighteen-pound unit gives real-time onsite sample analysis. Mass range is twelve to two hundred atomic mass units with resolution of two hundred. Device has biomedical application possibilities, such as determination of alcohol and gas content of blood and breath.
A mass spectrometer (MS) with unique magnetic pole pieces which provide a homogenous magnetic field across the gap of the MS magnetic sector as well as the magnetic field across an ion-type vacuum pump is disclosed. The pole pieces form the top and bottom sides of a housing. The housing is positioned so that portions of the pole pieces form part of the magnetic sector with the space between them defining the gap region of the magnetic sector, through which an ion beam passes. The pole pieces extend beyond the magnetic sector with the space between them being large enough to accommodate the electrical parts of an ion-type vacuum pump. The pole pieces which provide the magnetic field for the pump, together with the housing form the vacuum pump enclosure or housing.
Device uses lighter, easily alined, magnet assembly to provide field required to interact with ion beam. It has no separate duct; instead, evacuated duct is formed by pole pieces which support vacuum pump. Magnetic gap and magnet assembly are reduced from 4.64 to 2.54 mm and from 2.4 to 1.5 kg, respectively.
Science aspects of a 1980 spacecraft reconnaissance of Comet Encke are considered. The mission discussed is a ballistic flyby (more exactly, a fly-through) of P/Encke, using either a spin stabilized spacecraft, without despin of instruments, or a 3-axis stabilized spacecraft.
The minimum scientific spacecraft instrumentation is considered that is likely to result in as complete an understanding of the composition, structure, and activity of a cometary nucleus as is possible without landing on it. The payload will also give useful results on secondary goals of a better understanding of physical processes in the inner and outer coma. Studies of composition, by means of an actual landing on the surface, details of the internal structure of the nucleus, and sample return were considered beyond the scope of this mission.
This paper describes the development of an electro-optical ion detector combining the best features of photographic and electrical ion detection (i.e., wide mass range coverage and low ion detection threshold respectively). A nineteen fold fiber optic image dissector is discussed which reformats the 1 mm x 361 mm mass spectrometer focal plane format to a 19 mm x 19 mm format suitable for vidicon imaging and electronic display of the data.
Wedge-shaped microchannel electron multiplier array has been proposed to improve sensitivity of focal-plane mass spectrometer by two to four orders of magnitude.
System performs rapid multiple analyses of entire compound classes or individual compounds on small amounts of sample and reagent. Method will allow screening of large populations for metabolic disorders and establishment of effective-but-safe levels of therapeutic drugs in body fluids and tissues.
Results are presented of an investigation of the feasibility of a 1980 flyby of Comet Encke using a Pioneer class spacecraft. Specific areas studied include: science objectives and rationale; science observables; effects of encounter velocity; science encounter and targeting requirements; selection and description of science instruments; definition of a candidate science payload; engineering characteristics of suggested payload; value of a separable probe; science instruments for a separable probe; science payload integration problems; and science operations profile.
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The design and fabrication of a completely portable, self-contained gas chromatograph is described. This instrument utilizes a closed-loop hydrogen carrier gas flow as maintained by a hydrogen generator-separator. It employs an auxiliary hydrogen generator to keep a positive flow of hydrogen through the detector. The detector is an ionization cross section detector. The only maintenance required is the addition of water (5-15 cc/day) to the auxiliary hydrogen generator. Lower limit of detection for the present system is of the order of 1-10 ppm ethane.
Earth ecosystem chemical composition compared with Mars and Venus ecosystems to determine presence of life
Scientific objectives and experiments for comet mission
Mission planning and experiment design for future Mariner-type Venus space probes