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An experimental method is described for measuring the density of oxide traps in the gate oxide of an MOS transistor as a function of energy and position near the silicon interface. Measurements are obtained from different oxide growth processes and after Co-60 irradiation. The results are related to long-term drift of threshold voltage.
Trapped rubber processing is a molding technique for composites in which precast silicone rubber is placed within a closed cavity where it thermally expands against the composite's surface supported by the vessel walls. The method has been applied by the Douglas Aircraft Company, under contract to NASA-Langley, to the design and fabrication of 10 DC-10 graphite/epoxy upper aft rudder assemblies. A three-bay development tool form mold die has been designed and manufactured, and tooling parameters have been established. Fabrication procedures include graphite layup, assembly of details in the tool, and a cure cycle. The technique has made it possible for the cocured fabrication of complex primary box structures otherwise impracticable via standard composite material processes.
A series of parametric investigations are described which determine the effect of various fluid charges on the performance of a 0.635-cm-diam spiral-artery, liquid-trap diode in both the forward and reverse modes. Specific parameters such as forward- and reverse-mode conductances, shutdown times and energies, and recovery to forward-model operation, are evaluated for ethane as a working fluid in the temperature range 170 K to 220 K. Results indicate that the heat pipe will not reliably start up in the forward mode. However, startup can be initiated when preceded by a diode reversal. Also included are data which show the susceptibility of the diode to fluid charge and tilt. The optimum fluid charge was found to be 2.67 g and transport capability at this charge was in excess of 1200 W-cm at 200 K. The diode in the reverse mode exhibited a rapid shutdown (within 9 min) with a shutdown energy of 1150 J (0.32 Wh).
Some field-geometric features of relevance to particle trapping in the inner magnetosphere and polar-cap regions of Jupiter are described using an internal-field model that includes terms up to the order of n equals 3 (octupole). Adiabatic particle parameters for detectors on Pioneers 10 and 11 during their flights through Jupiter's inner magnetosphere are determined along with the configuration of the intersections of particle drift shells with the planetary ionosphere. Possible correlations between drift-shell contours and the planet-locked characteristics of Jovian decametric radio emission are investigated, and longitudinal asymmetries of the ionospheric plasma source function are analyzed. It is shown that if the ionosphere is the main source of magnetospheric plasma, the latitude dependence of the plasma source function should have a considerable effect on the longitudinal asymmetry of the corotating plasma.
Magnetic flux trapped in the rotor of a superconducting gyroscope can cause the rotor to lose energy through dissipation in a readout loop encompassing the rotor and by the generation of eddy currents in the support electrodes. These losses are calculated and shown to be negligible for the rotor in the gyroscope-relativity experiment, a proposed satellite experiment which is to test predictions of the theory of general relativity.
A summary and intercomparison of recent inner radiation zone electron data are presented. The morphology of the inner radiation zone is described and the data compared with the current generation of inner zone trapped electron models. An analytic representation of the inner zone equatorial pitch angle distribution is presented. This model was based upon data from eight satellites and was used to reduce all data to the form of equatorial flux. Although no Starfish-free high energy electron measurements were available from the inner portion of the inner radiation zone, it was found that the AE-6 model provided a good description of the present solar maximum environment.
A Dewar system and associated equipment for electron paramagnetic resonance (EPR) studies of trapped free radicals and other optical or irradiation experiments are described. The apparatus is capable of reaching a temperature of 1.5 K and transporting on the order of 20 W per K temperature gradient; its principal advantages are for use at pumped cryogen temperatures and for experiments with large heat inputs. Two versions of the apparatus are discussed, one of which is designed for EPR in a rectangular cavity operating in a TE(102) mode and another in which EPR is performed in a cylindrical microwave cavity.
Thermally stimulated conductivity studies have been performed on unirradiated borosilicate glasses made to contain various amounts of sodium, lithium, nickel, and iron oxides. Measurements were made between 77 and 570 K. All the samples gave one or more conductivity peaks below room temperature. Analysis of the initial-rise slope of the conductivity peaks of the various samples gave trapping-level energies ranging from 0.1 to 1.9 eV. The shape and temperature of the maximum of most of the peaks changed on each measurement cycle. A few samples exhibited a common peak that formed on annealing.
The paper examines the detailed time structure of high-energy (over 30 keV) electron precipitation along the morningside and dayside of the auroral zone. To this end, available high time resolution data from the Ogo 6 energetic electron experiment are analyzed. The relationship between trapped flux levels and degree of precipitation observed is studied from an observational standpoint and compared with the critical flux levels estimated by Kennel and Petschek (1966). A possible explanation within the general framework of the Kennel-Petschek theory of the observed burstlike precipitation episodes is presented, and the implications of these features for the average lifetime of electrons in drifting clouds are discussed.
The test results which were obtained with the HEPP liquid trap diode heat pipe prototype after it had been in storage for almost 27 months are presented. Transport data were obtained over the range of 150 to 220 K and reverse mode shutdown was measured with nominal operation at 180 K.
An investigation of noble gas entrapment during synthesis of carbonaceous, macromolecular, and kerogen-like substances is presented. High molecular weight organic matter synthesized in aqueous condensation reactions contained little gas, and the composition was consistent with fractionation due to noble gas solubility in water; however, propane soot produced during a modified Miller-Urey experiment in an aritificial gas mixture contained high concentrations of trapped noble gases that displayed strong elemental fractionation from their reservoirs. It is concluded that theses experiemnts show that processes exist for synthesis of carbonaceous carriers that result in high noble gas concentrations and strong elemental fractionation at temperatures well above those required by absorption to achieve similar effects.
The general solution to the bearing axis motor torque required to escape a minimum energy trap state is presented for oblate dual-spin spacecraft. A simplified, reduced order analysis of the bearing torque is then obtained for the case of small static imbalances, dynamic imbalances, and asymmetries on the rotor and the stator. This analysis is extended to include large asymmetry on one of the bodies. The results are applied to the design of the Galileo spacecraft.
Electrons and protons of energies from 2 to 25 MeV and greater than 67 MeV, respectively, have been discovered throughout the entire equatorial region inward from the outer edge of the A ring at L = 2.3 to the periapsis of the Pioneer trajectory at L = 1.3. The trapped radiation found in Saturn's magnetosphere beyond L = 2.3 is totally absent here. The present paper deals with the measurements in this region under the rings, and their interpretation.
A summary is given of basic formulas for the guiding center motion of energetic charged particles trapped in a dipolar magnetic field. These formulas for longitudinal drift rates, latitudinal bounce periods, equatorial gyroradii, and equatorial gyroperiods are then stated in convenient numerical form for electrons and protons as functions of kinetic energy E, magnetic shell parameter L, and equatorial pitch angle alpha 0 for a slightly simplified model of the observed magnetic field of Saturn. To aid in the study of the interaction of charged particles with the rings and inner satellites of Saturn, additional formulas are given for the time interval between successive encounters of charged particles with a satellite in a circular prograde orbit and for the energy of electrons whose longitudinal angular velocity is resonant, or synchronous, with the Keplerian angular velocity of such a satellite.
It has been suggested that energetic ions observed in the magnetosheath may be due to the direct leakage of trapped magnetospheric ions. To test this hypothesis, three-dimensional ion spectra from the energetic particle experiment on ISEE 1 for a magnetopause crossing on Nov. 10, 1977 are utilized to construct three-dimensional distribution functions in the magnetosphere and in the sheath. Using the observed magnetic field, a simple one-dimensional model of the magnetopause is developed. Ions are then followed in the model, starting in the magnetosphere, through the magnetopause and ending up in the sheath. Using Liouville's Theorem a model sheath distribution function is then built up by following the magnetospheric distribution function through the model fields. The model distribution is then compared with the observed sheath distribution. For this case it is found that the main features of the observed ions in the sheath are consistent with direct leakage and with no energization or de-energization processes, and an inward-pointing normal component is required. The energetic particles mapped in this case apparently follow a flux tube which does not penetrate the magnetopause where local tangential electric fields have been reported.
A brief review is given of the problem of precipitation of auroral electrons by electrostatic Bernstein waves. Since the magnetospheric loss cone is small, only moderately small intense levels of wave turbulence are required to remove any large anisotropy sources of free energy and to maintain a weakly anisotropic electron distribution on strong diffusion precipitation. The electrostatic electron cyclotron harmonic waves are nonconvectively unstable for weak loss cone anisotropies and over a large range of parameters for both the hot and cold distributions. Since the instability is nonconvective, weak wave growth can be maintained independent of the flux level of the hot electrons, i.e., the instability does not have the stably trapped flux limit imposed by convective amplification. Recent plasma numerical simulations show that the nonlinear evolution of this instability involves both the pitch angle diffusion of the hot electrons and the heating of the cold electrons.
Redistribution reaction section of silane process progressively separates heavier parts of chlorosilane feedstock until light silane product is available for pyrolysis. Small amount of liquid containing impurities is withdrawn from processing stages in which trapping occurs and passed to earlier processing stage in which impurities tend to be removed via chemical reactions.
Mercury 199 ions confined in an RF quadrupole trap and optically pumped by mercury 202 ion resonance light are investigated as the basis for a high performance frequency standard with commercial possibilities. Results achieved and estimates of the potential performance of such a standard are given.