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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.
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Vacuum dielectric capacitor is fabricated from materials with very low temperature coefficients of expansion. This precision capacitor in the 1000-2000 picofarad range has a near-zero temperature coefficient of capacitance, eliminates ion chamber action caused by air ionization in the dielectric, and minimizes electromagnetic field charging effects.
Gamma ray exposure rates in Plum Brook HB-6 facility measured with dosimeters and ion chambers
The efficiency of the electron-bombardment thrustor is approaching the maximum that can be expected. Desired lifetimes (of the order of 10,000 hr) have not yet been reached, but present knowledge indicates such lifetimes should be obtainable, The simplicity of this thrustor makes it interesting as an ion source for various laboratory experiments. Various gases have been used to determine the ion-chamber and accelerator performance for such applications.
Ionization rate profiles from solar flare X rays observed by ion chambers aboard OGO 1 and OGO 3
Ionization rate and omnidirectional radiation flux in interplanetary space measured by similar ion chambers and GM tubes on Mariners 2 and 4
Transistor-driven temperature-stable amplifier with logarithmic operating characteristics permits presentation of the entire range of the reactor without range switching. This circuit is capable of monitoring ion chamber currents over spans of 8 or 9 decades and is used in nuclear reactor instrumentation. Application is found in materials under ultrahigh vacuum.
Peaks and time intensity profile of energetic X rays and cosmic rays observed by OGO-C ion chamber on May 23, 1967 flare event
Graphical and tabular summaries of ionization rates in space recorded by OGO spacecraft ion chambers
Relationships between solar soft X radiation and emissions at other wavelengths based on data from ion chamber phototometer aboard OSO-3
Solar soft X rays and solar activity observed with ion chamber photometer
Hysteresis effect on cosmic ray modulation and gradient ionization near solar minimum from measurements made near earth with OGO 1 and 3 ion chambers
Submillipound mercury electron bombardment ion thrustor efficiency, noting cathode pole piece, baffle position and geometry influence on ion chamber performance
Conversion factor for converting Geiger tube count rates or ion chamber currents into units of incident X ray energy flux in specified passband in normalizing solar X ray data
Submillipound mercury electron bombardment ion thrustor efficiency, noting cathode pole piece, baffle position and geometry influence on ion chamber performance
Low energy cosmic rays modulation and heliocentric gradient during solar minimum, comparing OGO 1 and 2 ion chamber measurements with other space and ground observations
Photon intensities of UV spectral lines from energetic magnetically confined vacuum carbon arc, using monochromator double ion chamber detector system
The optical radiation from the plasma discharge of an electron bombardment mercury ion thrustor was investigated. Using the measured ratio of the Hg I line amplitude at 3655 A to that at 3650 A, a theory incorporating a bimodal electron distribution (Maxwell electrons plus primary electrons) was used to obtain the average electron temperature and primary electron fraction in the thruster ion chamber. The electron temperature ranged from about 1.2 eV to 6.6 eV; whereas the primary electron fraction varied from zero percent to about 5 percent. These values depended upon the discharge voltage and the radial location of the measurement. The percentage of doubly ionized mercury produced in the chamber was also determined as a function of discharge voltage.
Type III solar bursts occurring in the absence of solar flares were observed to be accompanied by weak X-radiation. The energy scale of an OSO-3 soft X-ray ion chamber was assessed using realistic theoretical X-ray spectra. Relationships between soft solar X-rays and solar activity were investigated. These included optical studies, the role of the Type III acceleration mechanism in establishing the soft X-ray source volume, H alpha flare intensity variations, and gross magnetic field structure.