Abstract: An instrument for obtaining quantitative, three-dimensional and tomographic information relating to x-ray and gamma-ray emitting objects and for the orthoscopic viewing of such objects includes a multiple-pinhole aperture plate (22) held spaced from an x-ray or gamma-ray to visible-light converter (24) which is coupled to a visible-light image intensifier (26). The spacing between the aperture plate and the converter is chosen such that the mini-images of an emitting object formed by the pinholes do not substantially overlap as they impinge on the converter. The output of the image intensifier is digitized by a digitizing camera (36) in terms of position and intensity and fed into a digital computer (40,42). The computer may output quantitative information relating to the emitting object directly, such as that relating to tomograms, or provide information in analogue form when coupled with a suitable viewing device (52,54), to give an orthoscopic, three-dimensional image of the object.

Abstract: A highly diffuse, reflective paint comprising an alcohol soluble binder, polytetrafluoroethylene (TFE) and an alcohol for coating a substrate and forming an optical reference with a superior Lambertian characteristic. A method for making the paint by first mixing the binder and alcohol, and thereafter by mixing in outgassed TFE. A wetting agent may be employed to aid the mixing process.

Abstract: A high voltage power supply is formed by three discrete circuits (12, 14, 16) energized by a battery (18) to provide a plurality of concurrent output signals floating at a high output voltage on the order of several tens of kilovolts. Each circuit has a regulator stage (20, 28, 36). In the first two circuits, the regulator stages are pulse width modulated and include adjustable resistances (R1, R2) for varying the duty cycles of pulse trains provided to corresponding oscillator stages while the third regulator stage includes an adjustable resistance (R3) for varying the amplitude of a steady signal provided to a third oscillator stage.

Abstract: A high voltage isolation transformer (10) is provided with primary (30) and secondary (32) coils separated by discrete electrostatic shields from the surfaces of insulating spools (12,14) on which the coils are wound. The electrostatic shields are formed by coatings (49,59,50,60) of a compound having a low electrical conductivity which completely encase the coils and adhere to the surfaces of the insulating spools (12,14) adjacent to the coils. Coatings (47,48) of the compound also line axial bores of the spools, thereby forming electrostatic shields separating the spools from legs (18,20) of a ferromagnetic core (16) extending through the bores. The transformer is able to isolate a high constant potential applied to one of its coils, without the occurrence of sparking or corona, by coupling the coatings lining the axial bores to the ferromagnetic core and by coupling one terminal of each coil to the respective coating encasing the coil.

Abstract: A vibration free fluid compressor particularly adapted for Stirling cycle cryogenic refrigeration apparatus comprising a pair of identical opposing ferromagnetic pistons (10, 12) located in a housing (22) and between a gas spring including a sealed volume (52, 54, 60) of a working fluid such as gas under pressure. The gas compresses and expands in accordance with movement of the pistons (10, 12) to generate a compression wave which can be vented out to other apparatus, for example, a displacer unit in a Stirling cycle engine. The pistons (10, 12) are urged outwardly due to the pressure of the gas; however, a fixed electromagnetic coil assembly (56), located in the housing adjacent the pistons, is periodically energized to produce a magnetic field which interlinks the pistons (10, 12) in such a fashion that the pistons are mutually attracted to one another.

Abstract: In a method of and apparatus for making remote measurements of temperature and pressure in a gas, laser beams are transmitted through the gas to a reflecting target, which may be either a solid surface or particulate matter in gas or the gas molecules and the return beams are measured to determine the amount of energy absorbed by the gas. For temperature measurements, the laser beam has a wavelength whereat the gas exhibits a relatively temperature sensitive and pressure insensitive absorption characteristic, whereas for pressure measurements, the laser beam has a wavelength whereat the gas has a relatively pressure sensitive and temperature insensitive absorption characteristic. To reduce the effects of scattering on the absorption measurements, a reference laser beam having a weak absorption characteristic is transmitted colinearly with the data beam having a strong absorption characteristic. The two signals are processed as a ratio to eliminate back scattering that is common to the two beams.

Abstract: A neutron/gamma ray technique for mapping the distribution of contaminants in an extended medium such as the wall (10) of a building. A neutron excitation source (14) is located on one side of the wall (10) and a gamma ray spectrometer, including a gamma ray detector (16), is located on the opposite side of the wall (10) facing the excitation source (12). The source and detector are moved in unison in discrete steps over opposing wall surfaces (12, 18) so as to determine the chemical composition of the elements in a hemispheric region (20) of the wall adjacent the detector with the radius of the region being substantially that of the mean free path distance of gamma rays emitted from elements interacting with neutrons on the detector side of the wall. The source (14) and detector (16) are reversed for relatively thick walls for mapping the distribution of elements on the other side of the wall thickness.

Abstract: An assembly (10) for use with several like units in weighing the mass of a loaded cargo pallet supported by its trunnions (12) has a bridge frame (20) for positioning the assembly on a transportation frame carrying the pallet while straddling one trunnion of the pallet and its trunnion lock, and a cradle assembly (60) for incrementally raising the trunnion. The mass at the trunnion is carried as a static loading by a slidable bracket (40) mounted upon the bridge frame for supporting the cradle assembly. The bracket (40) applies the static loading to an electrical load cell (80) symmetrically positioned between the bridge frame (20) and the bracket (40). The static loading compresses the load cell, causing a slight deformation and a potential difference at load cell terminals (86) which is proportional in amplitude to the mass of the pallet at the trunnion.

Abstract: The useful life of the wire probe in an ultrasonic kidney stone disintegration instrument is enhanced and prolonged by attaching the wire (24) of the wire probe to the tip (26) of an ultrasonic transducer (28) by means of a clamping arrangement comprising opposing set screws (60, 65), one (60) of which is adapted to accept the clamping load from the other set screw (65) without deforming the wire by machining a pair of mutually transverse grooves (64) in the inner end face (62) of the screw (60) which is adapted to accept and hold the wire probe along the central longitudinal axis (52) of the transducer tip which is adapted to impart ultrasonic energy to the wire. Additionally, damping material is applied to the wire probe (24) in the form of a damper tube (70) through which the wire probe passes in the region adjacent the transducer tip. The damper tube extends outwardly from the transducer tip (26) a predetermined distance, terminating in a resilient soft rubber joint (72).

Abstract: An X-ray spectrometer for providing imaging and energy resolution of an X-ray source comprised of a thick silicon wafer (10) having an embedded matrix or grid of aluminum completely through the wafer fabricated, for example, by thermal migration. The aluminum matrix defines the walls (16, 18) of a rectangular array of silicon X-ray detector cells (14) or "pixels". A thermally diffused aluminum electrode (20) is also formed centrally through each of the silicon cells (14) with biasing means (22, 26, 28) being connected to the aluminum cell walls (16, 18) and the centralized aluminum electrode (20) for causing lateral charge carrier depletion between the cell walls so that incident X-ray energy causes a photo-electric reaction within the silicon producing collectible charge carriers in the form of electrons which are collected and used for imaging.

Abstract: Compensation is provided for dynamic unbalance imparted to a fixed body by a rotating body that is connected to the fixed body by a shaft about which the rotating body rotates. Force components exerted on the fixed body by the rotating body in a plane at right angles to the axis are determined. In response to the determined force components, the rotational speed and effective direction of mass means mounted on the rotating body are controlled. The mass means has an effective axis of rotation in a plane at right angles to the longitudinal axis.

Abstract: A workpiece holding vise (10) uses a pair of jaw assemblies (12, 14) simultaneously driven in opposed reciprocation by a single shaft (26) having oppositely threaded sections to automatically center a workpiece (60) beneath a tool. Both jaw assemblies (12, 14) are suspended above the vise bed (20) by a pair of parallel guide shafts (56, 58) attached to the vise bed. Linear rolling bearings (54) fitted around the guide shafts and firmly held by opposite ends of the jaw assemblies (12, 14) provide rolling friction between the guide shafts (56, 58) and the jaw assemblies (12, 14). A bellville washer (46) at one end of the drive shaft (26) and thrust bearings at both drive shaft ends hold the shaft in compression between the vise bed (20), thereby preventing wobble of the jaw assemblies due to wear between the shaft and vise bed.

Abstract: Disclosed is a coherently optically pumped laser system wherein a pump laser beam (30) propagates through a laser medium contained in a degenerate cavity resonator (10) in a controlled multiple round trip fashion in such a way that the unused pump beam (30') emerges from an injection aperture (24) at a different angle (.beta.) from which it enters (.alpha.) the resonator. The pump beam (30) is angularly injected off of the central axis (22) of the resonator body (10) whereupon the pump beam alternately undergoes spreading and focusing (b.sub.1 . . . b.sub.8) while pumping the laser medium by a process of resonant absorption pumping. Means (32) are employed externally of the cavity resonator to sense the emergent output beam (30') which is used not only for alignment of the system but also to monitor the power of the emergent pump beam. The power in the emergent pump beam (30') provides a measure of the performance of the laser systems.

Abstract: In a global positioning system (GPS), such as the NAVSTAR/GPS system, wherein the position coordinates of user terminals (14) are obtained by processing multiple signals transmitted by a constellation of orbiting satellites (16), an acquisition-aiding signal generated by an earth-based control station (12) is relayed to user terminals via a geostationary satellite (10) to simplify user equipment. The aiding signal is FSK modulated on a reference channel slightly offset from the standard GPS channel. The aiding signal identifies satellites in view having best geometry and includes Doppler prediction data as well as GPS satellite coordinates and identification data associated with user terminals within an area being served by the control station (12) and relay satellite (10). The aiding signal significantly reduces user equipment by simplifying spread spectrum signal demodulation and reducing data processing functions previously carried out at the user terminals (14).

Abstract: A dual aperture, off-axis catadioptic Schmidt objective (40) is formed by symmetrically aligning two pairs of Schmidt objectives (12, 14) on opposite sides of a common plane (x, z). Each objective has a spherical primary mirror (16/18) with a spherical focal plane (44/46) and center of curvature (20/22) aligned along an optic axis (36/38) laterally spaced apart from the common plane. A multiprism beamsplitter (44/46) with buried dichroic layers (81-83) and a convex entrance (48) and concave exit (52a-52f) surfaces optically concentric to the center of curvature may be positioned at the focal plane. The primary mirrors of each objective may be connected rigidly together and may have equal or unequal focal lengths.

Abstract: A bandpass amplifier employing a field effect transistor amplifier first stage (10) with a resistive load (R.sub.2) either a.c. or directly coupled to the non-inverting input of an operational amplifier second stage (20) which is loaded in a Wien Bridge configuration. The bandpass amplifier may be operated with a signal injected into the gate terminal (G) of the field effect transistor and the signal output taken from the output terminal of the operational amplifier. The operational amplifier stage appears as an inductive reactance, capacitive reactance and negative resistance at the non-inverting input of the operational amplifier, all of which appear in parallel with the resistive load (R.sub.2) of the field effect transistor.

Abstract: A memory-based parallel data output controller employs associative memories and memory mapping to decommutate multiple channels of telemetry data. The output controller contains a random access memory (RAM) (10) which has at least as many address locations as there are channels. A word counter addresses the RAM (10) which provides as its outputs an encoded peripheral device number and a MSB/LSB-first flag. The encoded device number and a bit counter address a second RAM (20) which contains START and STOP flags to pick out the required bits from the specified word number. The LSB/MSB, START and STOP flags, along with the serial input digital data go to a control block (30) which selectively fills a shift register (40,42) used to drive the parallel data output bus (32). A strobe pulse is also generated which enables a decoder (34) to select the appropriate peripheral device using the encoded device number.

Abstract: A low noise RF signal phase comparator comprised of two high stability driver-buffer amplifiers (16 and 18) driving a double balanced mixer (14) which operate to generate a beat frequency between the two RF input signals coupled to the amplifiers from the RF sources. The beat frequency output from the mixer is applied to a low noise zero crossing detector (20) which generates a square wave output whose positive and negative going edges provide a measure of the phase difference between the two RF inputs. Temperature stability is provided by mounting the amplifiers (16 and 18) and mixer (14) on a common circuit board (29) with the active circuit elements (62, 68, 70, 82, 88, 90, 110) thereof being located on one side of a circuit board (29) while the passive circuit elements (112) are located on the opposite side.

Abstract: A variable, thermal control system (10) for regulating the temperature of an exothermic process plant carried aboard an earth orbiting spacecraft is made with a plurality of curved radiator panels (14) arcuately positioned in a circular arrangement to form an open receptacle. A module (12) containing the process is insertable into the receptacle. Heat exchangers (42) having broad exterior surfaces (43) extending axially above the circumference of the module (12) fit within arcuate spacings (18) between adjacent radiator panels (14). Banks of variable conductance heat pipes (24) partially embedded within and thermally coupled to the radiator panels (14) extend across the arcuate spacings (18) and are thermally coupled to broad exterior surfaces (43) of the heat exchangers by flanges (26). Temperature sensors (86) monitor the temperature of process fluid flowing from the module through the heat exchanges.

Abstract: An optical resonator cavity configuration 10 using a unitary mirror 50 with oppositely directed convex reflective surface 52 and concave reflective surface 54 disposed into one fold and concertedly reversing both ends of a beam propagating from a laser rod 20 disposed between two total internal reflection prisms 30, 32 rigidly positioned with perpendicularly crossed virtual rooflines 35, 37 by a compact optical bed 80. The rooflines 35, 37 of the internal reflection prisms 30, 32 are arranged perpendicularly to the axis of the laser beam and to the optical axes of the optical resonator components.