Abstract: An improvement in a magnetically focused image intensifier for increasing the usable range of magnification without degradation of image quality and while keeping to a minimum the power requirements of the focusing coils. The improvement comprises an arrangement of focusing coils which reverses the direction of the axial magnetic field distribution between the planes of the photocathode and the phosphor screen.

Abstract: A method for detecting and measuring trace amounts of aerosols when reacted with ozone in a gaseous environment wherein a sample aerosol is exposed to a fixed ozone concentration for a fixed period of time, a fluorescer added to the exposed sample and thereafter the sample heated in a 30.degree. C/minute linear temperature profile to 200.degree. C. undergoes thermoluminescence the trace peak thereof is measured and recorded as a function of the test aerosol and wherein the recorded thermoluminescence trace peak of the fluorescer is specific to the aerosol being tested.

Abstract: A scattering photometer for measuring the light scattered by particles in a hydrosol at substantially 2.degree. and 90.degree. simultaneously. Light from a source is directed by a first optical system into a scattering cell containing the hydrosol under study. Light scattered at substantially 90.degree. to the incident beam is focused onto a first photoelectric detector to generate an electrical signal indicative of the amount of scattered light at substantially 90.degree.. Light scattered at substantially 2.degree. to the incident beam is directed through an annular aperture symmetrically located about the axis of the illuminating beam which is linearly transmitted undeviated through the hydrosol and focused onto a second photoelectric detector to generate an electrical signal indicative of the amount of light scattered at substantially 2.degree..

Abstract: A method of treating a surface of a glass member intended to abut a transparent element for disrupting the light interference fringes formed therebetween. The method involves the steps of grinding the surface to form irregularities thereon; bathing the surface with an aqueous solution containing between substantially 41.3 percent and 45.7 percent by volume of sulfuric acid and between substantially 54.3 percent and 58.7 percent by volume of hydrofluoric acid for a time sufficient to polish the irregularities until the glass member is about 90 percent light transmissive; and washing the glass member with a liquid having a temperature substantially lower than the temperature of the aqueous solution for preventing further reaction between the aqueous solution and the surface.

Abstract: A fluid sampling device for selectively sampling multiple fluids including a support frame. A plurality of fluid inlet devices extend through the support frame and each of the fluid inlet devices include a longitudinal aperture extending therethrough. An opening device that is responsive to a control signal selectively opens the aperture for passing the fluid therethrough. A closing device that is responsive to another control signal selectively closes the aperture for terminating further fluid flow therethrough.

Abstract: Flat-plate (vapor chamber) heat pipes are made by enclosing metal wicking between two capillary grooved flat panels. These heat pipes provide a unique configuration and have good capacity and conductance capabilities in zero gravity. When these flat-plate vapor chamber heat pipes are heated or cooled, the surfaces are essentially isothermal, varying only 3.degree. to 5.degree. C over the panel surface.

Abstract: Analog to digital converter for two-dimensional radiant energy array computers in which the converter stage derives a bit array of digital radiant energy signals representative of the amplitudes of an input radiant energy analog signal array and derives an output radiant energy analog signal array to serve as an input to succeeding stages. The converter stage includes a digital radiant energy array device which contains radiant energy array positions so that the analog array is less than a predetermined threshold level and which doesn't contain radiant energy at array positions where the input analog array exceeds the threshold level. A scaling device amplifies the radiant energy signal levels of the input array and the digital array so that the radiant energy signal level carried by the digital array corresponds to the threshold level. An adder device adds the signals of the scaled input and digital arrays at corresponding array positions to form the output analog array.

Abstract: Pseudo noise ranging codes, having a predetermined chipping rate, and a pair of binary data sources, each having a bit rate no greater than one tenth the chipping rate, quadriphase, digitally modulate a suppressed carrier wave having a first frequency. Two additional binary data sources, each having a bit rate that is not restricted by the chipping rate of the first carrier, quadriphase, digitally modulate a suppressed carrier wave having a second frequency. The first and second frequencies are only slightly displaced so that there is overlap in the frequency bands which modulate the two carriers. The two suppressed carrier waves are linearly combined and transmitted from a first station to a second station so that the amplitude of the transmitted first wave is controlled so as not to degrade the detectability of the second wave at the second station. At the second station, the information modulated on the second carrier is coherently detected to recover the two signals modulated on the second carrier.

Abstract: An opto-mechanical subsystem for supporting a laser structure which minimizes changes in the alignment of the laser optics in response to temperature variations. Both optical and mechanical structural components of the system are formed of the same material, preferably beryllium, which is selected for high mechanical strength and good thermal conducting qualities. All mechanical and optical components are mounted and assembled to provide thorough thermal coupling throughout the subsystem to prevent the development of temperature gradients.

Abstract: A method and apparatus for stabilizing the amplitude and repetition rate of mode-locked Nd:YAG laser pulses by controlling the laser length through a feedback loop is described. The end mirror of the laser is mounted on a piezoelectric crystal which is dithered at a low frequency. A portion of fundamental 1.06 micrometer laser radiation is converted into its second harmonic frequency and the average power of the second harmonic frequency is detected by an integrating detector. The amount of the power of the second harmonic frequency depends on the match between the optical length of the laser cavity and the mode-lock frequency. The length is controlled by a feedback loop which phase compares the output of the second harmonic detector to the piezoelectric crystal dither signal.

Abstract: An optical heterodyne receiver comprises a system of reflectors forming a folded Gregorian configuration for collecting a signal beam, and an optical detector located at the focus of the system. The reflectors comprise a paraboloidal primary reflector and an ellipsoidal secondary reflector facing each other on an optical axis with the focus of the secondary reflector coinciding with the focus of the primary reflector. An auxiliary laser generates a local oscillator beam that is combined with the signal beam after the signal beam emerges from the exit pupil (which is also the aperture stop) of the system, and the resultant is impinged on the detector. A pair of image motion compensators is located as close to the exit pupil as possible for aligning off-axis inputs to the detector. The compensators also ensure that off-axis as well as on-axis inputs are substantially coaxial with the local oscillator beam, thereby maximizing signal detector efficiency.

Abstract: A method of fabricating an inlet leak for measuring chemically reactive gases. The method involves the steps of preparing a selected internal surface of a high melting point metal tubing for sealing to a glass tubing; inserting a portion of the glass tubing into the prepared portion of the metal tubing, the glass tubing having an outer diameter substantially the same as the inner diameter of the metal tubing; sealing the inserted glass tubing to the internal surface of the metal tubing; drawing the glass tubing under a magnifying device to reduce the entire interior diameter thereof to substantially two microns; and breaking away an end portion of the drawn glass tubing.

Abstract: A potential induced on the surface of an orbiting spacecraft is neutralized to the potential of a plasma through which the spacecraft is traveling by directing charged particles into the plasma from the spacecraft surface. The induced potential occurs in response to bombardment of the spacecraft surface by ambient charged particles which may be negative or positive. The charged particles directed into the plasma from the surface have the same polarity as the induced potential to provide the neutralization. The invention can be utilized to maintain different, electrically isolated segments of a spacecraft surface at the same potential to prevent electric discharges between the different parts and thereby protect electric circuits within the spacecraft. The invention can also be utilized to enable charged particle detectors on the surface of a spacecraft to operate more accurately so that the particles are not perturbed by a potential difference between the spacecraft surface and the plasma.

Abstract: The static coefficient of friction between contacting surfaces of a plurality of bodies is determined by applying a load to the bodies in a direction normal to the contacting surfaces. Opposite ends of a flexible filament are fixedly connected to a load cell and a first of the bodies. A motor continuously moves a second of the bodies away from the load cell at constant velocity to pull the first body at right angles to the force of the normal load so that the first body moves intermittently relative to the second body across a contact surface between them. The load on the surfaces, the nature of the surfaces, and the speed of the first body relative to the load cell are such that the filament is alternately and cyclically tensioned and relaxed as the movement occurs. The maximum tension occurs at the incipient stages of movement of the first body relative to the second body.