Engineering topics
Publications and source records attributed to Roy, N. L..
Unit may be used in systems requiring milliwatt power for bias voltage functions and can be used as control mechanism for large electric power systems. Logic and energy storage techniques yield processing efficiencies of 1000 to 1 over conventional designs.
Signals from impact ionization plasmas were studied as a means of performing microparticle composition analysis. Impact ionization signal response was measured in a time-of-flight (TOF) system for lanthanum hexaboride, carbonyl iron, and aluminum microparticle impacts on a tantalum target, primarily in the 1 - 8 km/s velocity range. Oscilloscope photographs of representative ion TOF signal response are given for each material studied. Graphs and histograms are presented of the total charge collected as well as the charge collected in each observed ion mass group. Data show that ion signals consist primarily of the lower ionization potential elements over the 1 - 8 km/s range.
Laboratory tests with simulated micrometeoroids to measure the heat transfer coefficient are discussed. Equations for ablation path length for electrically accelerated micrometeoroids entering a gas target are developed which yield guidelines for the laboratory measurement of the heat transfer coefficient. Test results are presented for lanthanum hexaboride (LaB sub 6) microparticles in air, argon, and oxygen targets. The tests indicate the heat transfer coefficient has a value of approximately 0.9 at 30 km/sec, and that it increases to approximately unity at 50 km/sec and above. Test results extend to over 100 km/sec. Results are also given for two types of small particle detectors. A solid state capacitor type detector was tested from 0.61 km/sec to 50 km/sec. An impact ionization type detector was tested from 1.0 to 150 km/sec using LaB sub 6 microparticles.
Review of the theory, design parameters, and construction details of a linear accelerator designed to impart meteoric velocities to charged microparticles in the 1- to 10-micron diameter range. The described linac is of the Sloan Lawrence type and, in a significant departure from conventional accelerator practice, is adapted to single particle operation by employing a square wave driving voltage with the frequency automatically adjusted from 12.5 to 125 kHz according to the variable velocity of each injected particle. Any output velocity up to about 30 km/sec can easily be selected, with a repetition rate of approximately two particles per minute.
Electrostatically accelerated microparticles are used to perform simulated micrometeoroid impact cratering experiments in oligoclase. Impact craters were obtained using iron, lanthanum hexaboride, and silicon as the projectile materials. Each particle material was impacted at normal incidence and at 30 and 60 deg oblique angles. Tabular data for all impacts are presented and central crater pit diameter normalized to particle diameter and the total spall diameter normalized to particle diameter are plotted vs impact velocity for nine particle/angle combinations and three crystal orientations. Impact crater characteristics are photodocumented as a function of impact velocity for the nine particle/angle combinations and three crystal orientations in oligoclase and at fixed impact velocity for six other minerals.
A thermal equilibrium plasma model is used to process data from an impact ionization time-of-flight mass spectrometer in order to convert the raw ion data to relative abundances of the elemental constituents of cosmic dust particles.
Micrometeoroid linear accelerator for particle velocities up to 25 km/sec and thin film penetration studies
An X-Y plotter circuit apparatus is described which displays an input pulse representing particle parameter information, that would ordinarily appear on the screen of an oscilloscope as a rectangular pulse, as a single dot positioned on the screen where the upper right hand corner of the input pulse would have appeared. If another event occurs, and it is desired to display this event, the apparatus is provided to replace the dot with a short horizontal line.
An apparatus for handling, transporting, or size classifying comminuted material was described in detail. Electrostatic acceleration techniques for classifying particles as to size in the particle range from 0.1 to about 100 microns diameter were employed.
Solid state low noise preamplifier for particle detector of electrostatic accelerator system