Abstract: A CW Brillouin ring laser utilizing a low loss optical fiber and a pair of partially reflective mirrors positioned to form a ring optical path with the fiber ends, produces a Brillouin shifted Stokes beam when a pump beam is directed into one end of the optical fiber. The Brillouin beam propagates around the ring in a direction opposite to the pump beam. The pump beam is coupled into the ring through one of the partially reflective mirrors and the laser output is the portion of the Brillouin beam passing through the other partially reflective mirror. In the Brillouin laser system, a second pump beam may be directed into the other end of the fiber to produce a second Brillouin beam propagating in a direction opposite to the first Brillouin beam, providing a laser with two distinct Brillouin beam outputs.

Abstract: This bubble domain sensor is capable of sensing the presence or absence of a bubble at a predetermined location within bubble supporting material regardless of whether the bubble is stationary or moving through that location. A magnetostrictive material layer, such as a thin film having an area approximately equal to the area of a bubble domain, is positioned with respect to the bubble material such that it is magnetically influenced by the closure field of a bubble at the predetermined location. A conductor, such as a strip conductor, is positioned in contact with the magnetostrictive material. A sonic device launches sonic wave pulses which pass in the vicinity of the magnetostrictive material layer. The sonic wave pulse stresses the magnetostrictive material, and when the magnetostrictive material is magnetically influenced by a bubble, the stress changes or rotates its magnetization thereby inducing an electric signal in the conductor.

Abstract: The resistance temperature detector (RTD) includes a substrate of refractory dielectric material having two or more holes bored through it. A plug of electrically conductive material is fixed within each hole in proximity to one end surface of the substrate, with the plug surface preferably having a concave meniscus shape and consisting of a metal alloy such as Ti-Ni. Lead wires, such as Ni wires, are located in the holes and are connected to the plugs through the other end surface. A film of temperature dependent resistance material is deposited on the one end surface of the substrate and is connected to the two plugs. The film may consist of a thin sensing film of metal such as platinum or of a semiconductor material, deposited in a selected pattern on the substrate and in direct contact with the plugs, or the sensing film may be deposited so as to connect pads of electrical conducting material which are deposited to cover at least a portion of the plugs.

Abstract: The monitor is used with seeder equipment having one or more seeder hopper sections wherein each hopper section has a number of metering assemblies for feeding the seed from each hopper section to the soil. The monitoring apparatus includes at least one sensor consisting of a piezoelectric transducer which provides an output signal in response to being struck by a seed, a vibration isolating mounting structure to position the sensor in the seed flow path between the metering assembly and the soil, and a circuit for receiving the sensor electronic response and providing an indication of seed flow condition. The mounting structure includes an elongated member such as a metal tubing, to one end of which is fixed a cushion made of a material such as a closed cell foam and to the other end of which is fixed a securing member to secure the structure to the seeder.

Abstract: A continuous wave, phase measurement system which provides at least an order of magnitude improvement in accuracy over modulated carrier systems is disclosed for the determination of the thicknesses of layered targets consisting of a known number of dielectric layers, each of a known maximum thickness. This system uses related frequencies such as the fundamental and its harmonics to establish a multi-harmonic coherence relationship whereby a homodyne phase reference between harmonics can be conserved and information extracted from just the received and not the transmitted signals. Consequently doppler effects due to motion between the target and the apparatus, as well as severe local oscillator stability and drift limitations are avoided, and thus this system can measure remote target parameters by interferometric techniques without the distance being a constraint.

Abstract: A charged particle beam deflector having a bimodal resonant cavity through which a charged particle beam is passed along the cavity axis. The cavity is excited in a first mode by applying a first rf signal to the cavity through a first magnetic feed loop on the side of the cavity, and in a second mode orthogonal to the first mode by applying a second rf signal to the cavity through a second magnetic feed loop located on the side of the cavity at a circumferential angle of approximately 90.degree. from the first feed loop. The first mode deflects the beam along a first diametric axis passing through the cavity axis and the first loop location and the second mode deflects the beam along a second diametric axis which is substantially perpendicular to the first diametric axis. The rf signals to the feed loops are normally of identical frequency but may differ in ampitude and in phase from one another or from the beam to provide various controlled scan patterns.

Abstract: A charged particle beam position monitor having a resonant cavity which is excited in a first mode if the monitored beam passing through it is displaced along the x-axis, and is excited in a second mode orthogonal to the first if the monitored beam passing through it is displaced along the y-axis. These modes are tuned to the same frequency and may be independently detected. The X and Y coordinates of the beam are determined by the amplitude and phase of the detected first and second orthogonal modes respectively.

Abstract: The electron beam monitor includes two long, thin foil elements which are sequentially moved through an electron beam to be measured, in directions transverse to the beam and perpendicular to one another. The electron beam striking the elements produces forward directed bremsstrahlung radiation that is detected by a series of detectors which are positioned circumferentially about the beam path. A measuring circuit measures the radiation intensity as a function of the foil position to provide beam current, profile and position information. To simultaneously monitor a second beam travelling in a direction opposite to the first beam, a second series of detectors are positioned circumferentially about the beam path to detect forward directed radiation produced by the second electron beam as it strikes the foils.

Abstract: A multi-state memory cell which uses magnetic bubble domains in uniaxial material is described. The cell includes a channel in which a number of stable bubble positions separated by barriers is formed and on which select conductors are positioned to switch a bubble from one stable position to another on a threshold basis by means of coincident currents. A cell in accordance with this invention may take the form of a four-state-two conductor cell, two-bistable-state two-conductor cell, multi-state six conductor cell and six-state three-conductor cell and include destructive or non-destructive readout.

Abstract: A probe type high voltage attenuator for a pulse measuring system to provide an overall rise time of less than 50 picoseconds with a peak voltage capability of 20 kV. Attenuator perturbations at the 50 ohm impedance level are minimized by providing a high resistance in series with a lossy distributed transmission line. The reflection waves from the attenuator are absorbed by this lossy distributed transmission line minimizing perturbation of the source being measured. The attenuator is of a shielded type to minimize interference from extraneous fields.This invention is directed to an attenuator for use in the measurement of point voltage sources in electric circuits and in particular to an attenuator which produces minimum loading on high voltage sources in the measurement of fast rise time pulses.

Abstract: The differential thermal wattmeter for the ac/dc transfer of power includes a differential thermal converter as a "sum and difference" multiplier, with both ac and dc voltage and current signals simultaneously applied to both heaters. DC feedback to the current input speeds up the response and maintains thermal balance between the heaters, so that the output meter becomes a null indicator. This reduces and can eliminate the need for quadratic response. The requirement for exact matching of the thermal converters is also eliminated by effective interchange of the heaters.

Abstract: The magnetic bubble propagate circuit combines the forces on a bubble due to the properties of a modulated channel in a bubble material with the forces on the bubble due to a field produced by discrete magnetic poles P.sub.1 and P.sub.2 to move the bubble along a predetermined path. The channels may be modulated in width or in depth and be of the mesa or groove type so as to have a channel with periodically spaced stable bubbles positions O which are separated by barrier positions X. The poles P.sub.1 and P.sub.2 consist of soft-magnetic material bars which are placed either along the channel perpendicular thereto such that alternate ends of sequential bars overlap the channel between pairs of stable positions, each bar providing a pole P.sub.1 or P.sub.2, or along the channel parallel thereto such that the ends of the bars fall between adjacent pairs of stable positions, each bar providing a pole P.sub.1 and P.sub.2. The propagate circuit thus has repeated pattern O, X, P.sub.1, O, X, P.sub.2. The bars P.

Abstract: The control system monitors the input power to and the output from the dryer applicator, and varies the input power to the applicator as a function of change in applicator efficiency and input power. The control system may consist of a first and a second circuit. The first circuit receives a signal P.sub.in.sbsb.1 from a first monitor and a signal P.sub.out.sbsb.1 from a second monitor. These signals are combined into an efficiency signal .eta..sub.1 to which a reference efficiency signal -.eta..sub.o is added. An amplifier having a predetermined gain K amplifies the resulting signal to produce -K(.eta..sub.1 -.eta..sub.o). The second circuit adds the signals P.sub.in.sbsb.1 from the first monitor, -K(.eta..sub.1 -.eta..sub.o) from the first circuit and P.sub.in.sbsb.o, a signal representative of input power for a reference condition, to produce an output signal I.sub.in.sbsb.1 - [P.sub.in.sbsb.o + K(.eta..sub.1 -.eta..sub.

Abstract: An apparatus for monitoring the concentration of a vapor, such as heavy water, having at least one narrow bandwidth in its absorption spectrum, in a sample gas such as air. The air is drawn into a chamber in which the vapor content is measured by means of its radiation absorption spectrum. High sensitivity is obtained by modulating the wavelength at a relatively high frequency without changing its optical path, while high stability against zero drift is obtained by the low frequency interchange of the sample gas to be monitored and of a reference sample. The variable HDO background due to natural humidity is automatically corrected.

Abstract: The novel radiation source system of this invention includes a pair of electrodes which are coaxially mounted at each end of a single cylindrical transparent arc chamber. A liquid, such as water, is circulated through the arc chamber with a tangential velocity so as to form a vortexing liquid wall. The main functions of the liquid wall are to cool the periphery of the arc discharge between the electrodes thus constricting the arc diameter, and to absorb ultraviolet and infrared radiation which would otherwise be absorbed by the outer solid wall. This liquid wall produces a positive dynamic impedance for the arc discharge. In addition, a vortexing column of inert gas, injected through the length of the chamber, stabilizes the arc discharge between the electrodes.

Abstract: The coupler consists of an intermediate finite length waveguide located between a first and at least one second waveguide with the refractive index of the intermediate waveguide being greater than the refractive indices of the other waveguides. The intermediate waveguide further includes a structure which either in a fixed manner as by a surface relief, or in a controlled manner--as by electro-optic or acousto-optic perturbation, produces modes of propagation in the intermediate waveguide for a preselected frequency, such that energy may be coupled to or from the waveguides to the intermediate waveguide by mode matching and this energy may be converted from one mode to another in the intermediate waveguide.

Abstract: The klystron-resonant cavity accelerator system includes an accelerator structure having one or more sections of intercoupled resonant cavities which, with the output resonant cavity of a klystron, forms an integral rf coupled resonant cavity system for energizing the accelerator. The klystron and resonant cavity accelerator thus coupled also constitute a single evacuated system. The klystron output resonant cavity may be coupled to a resonant cavity in each of the accelerator sections by means of an energy coupling iris or by means of a intervening resonant coupling cell.

Abstract: A silicon photoelement imager which includes a photogeneration channel consisting of a layer of doped semiconductor material, located on a support substrate having a layer of oppositely doped semiconductor material. The photogeneration channel, in which carriers are photogenerated, has an optimum effective thickness of d/.pi., where d is the center to center spacing of the photoelements; while the support substrate is sufficiently thick to provide strength and rigidity to the device. The support substrate layer is further biased with respect to the photogeneration channel so as to drain and prevent any carriers produced in the support substrate from entering the photogeneration channel. This photogeneration channel substrate structure can be used to improve the spatial resolution of CCD and MOSFET imagers.

Abstract: A light beam scanner consisting of an acoustic cavity having a length l, a width w between two side surfaces and a thickness t between the other two side surfaces. The cavity is transparent to optical energy and is capable of supporting acoustic energy of frequency f reflected through the length of the cavity at an angle of incidence .theta. to the remaining surfaces, where ##EQU1## WHERE M IS AN INTEGER AND V IS THE VELOCITY OF ACOUSTIC ENERGY IN THE CAVITY. Acoustic waves at a controlled frequency f are generated in one end of the cavity from one of the remaining side surfaces so as to have a continuous distribution of direction. A beam of collimated monochromatic light having a wavelength .lambda. is directed onto one of the side surfaces either substantially perpendicular to it or at the Bragg angle, to be transmitted through the cavity and diffracted by the acoustic energy in the cavity. Focussing means focusses the diffracted beam onto a plane where it appears at a point .theta.

Abstract: An optical coupler for a multi-mode optical fiber transmission line consisting of a first length of optical fiber and a second length of optical fiber positioned along a common axis such that one end of the second fiber is spaced a predetermined distance l from one end of the first fiber. This allows a portion of the optical energy leaving the end of first fiber to enter the second fiber. The coupler further includes a reflective surface facing the first fiber to reflect the remaining portion of the optical energy out of the coupler. The percentage of the energy reflected out of the coupler is determined by the distance l and may be varied by moving the second fiber with respect to the first. The material between the ends of the fibers has a refractive index substantially identical to the refractive index of the fiber cores to provide for greater efficiency.