Abstract: A spiral passage chemical converter-heat exchanger formed by a cross-sectally rectangular housing containing a pair of rows each containing a plurality of side-by-side passages. The rectangular housing is wound into a spiral with the innermost row forming inlet passages and the outermost row forming outlet passages. Thermal contact exists between inflow passages and outflow passages. The outer end of the spiral is connected with an inlet and an outlet. The inlet joins the innermost row of passages and the outlet joins the outermost row of passages. The inner end of the spiral is capped, with a common wall separating the upper and lower passages slotted so that fluid flows from the inlet passages to the outlet passages. As can be seen when the structure is in a spiral, the inlet passages are between the outlet passages with the outlet passages forming the outer exposed surface of the spiral and the inlet passages forming the surface of the opening through the spiral at the center.

Abstract: A device for producing extended plasmas for x-ray lasers. In an evacuated using, a pair of tungsten blocks are placed just above a target surface and spaced apart to form a channel. A high power laser beam is focused to a point on the target creating a plasma between the blocks. As the plasma expands away from the target in the z-direction, the tungsten blocks confine the plasma in the y-direction and plasma species of higher stages of ionization are formed into a jet of rectangular x-y cross section in the z-direction by the blocks. The plasma remains confined in the y-dimension or is focused in this direction above the blocks where sufficient amplification occurs to provide x-ray lasing along the x-axis.

Abstract: A stimulated emission device operative in the ultraviolet and soft x-ray regions. A high-power infrared laser is focused on a slab target vaporizing the material and generating highly stripped target ions with varying velocities. Just prior to laser initiation, a gaseous environment of helium, hydrogen, argon or neon is injected to surround the target (e.g., carbon) at a pressure of from 1-10 Torr. The injected gas and associated electrons modify and mix the interacting particles originating from the vaporized target. Ion-atom resonance, charge-transfer reactions take place to form excited-state ions to produce amplified stimulated emission in the 300-800 Angstrom region.

Abstract: The invention is a magnetically tunable bandpass filter for use in the miwave regions, particularly for frequencies between 0.1-4 GHz. A magnetically tunable bandpass filter is a filter which will pass only certain frequencies from one conductor to a separate conductor depending upon the frequency band and the magnetic field applied across the filter. The tuning of the center frequency can be achieved at relatively fast electronic switch times. The center frequency is the frequency at which the most coupling exist due to the applied magnetic field. Two striplines are placed at 90.degree. relative to one another with one end of one stripline overlapping one end of the other with the overlapped ends connected to ground. A disc of ferromagnetic material is placed between the two striplines.

Abstract: A system and method of detecting stray electrical currents that cause corrosion on metallic structures submerged in electrolytic media. The system makes use of a plurality of metal plates in an arrangement so they will be bipolar electrodes in a stray current field and the stray currents are determined by the color of the plates. The amount of stray currents are determined by the amount of metal loss over a period of time. Plates may be placed about a ship's hull, or other submerged structures, or suspended in an open area of solution to locate areas of stray currents.

Abstract: A reflex tetrode device for efficiently generating intense, pulsed unidirional ion beams. The device includes two thin, semitransparent anodes spaced from a real cathode which is maintained at ground potential. The first anode is spaced from and faces the real cathode. The second anode is spaced a short distance from the first anode and a virtual cathode is formed beyond the second anode when a sufficiently high electron current flows from the real cathode and through the anodes. The anodes are ring-like or disc-like structures secured to the edges of a support member with their planes perpendicular to the axis of the device between the real and virtual cathodes. The anode structure (i.e., the support member together with the two anodes) is connected to a pulsed high-voltage generator which is operated in positive polarity. Consequently, both anodes are at the same positive potential.

Abstract: A fiber optic hydrophone for use as an underwater electroacoustic standard. The hydrophone includes a fiber optic acoustic wave detector in one end of the hydrophone which is subjected to incident acoustical waves. A similar fiber optic is in an acoustically isolated compartment where the optic fiber is not affected by the incident acoustical wave. Comparison of light passing through each coil will determine incidence of an acoustical wave on the detector fiber.

Abstract: A system for varying specific gravity of a submersible or any immersed obt under a pressurized environment which includes a compressible piston designed to collapse a certain amount proportional to the submersible's depth so that the specific gravity of the submersible or other immersed object varies and remains almost equal to the specific gravity of the surrounding medium such as water.

Abstract: An electrooptical analog-to-digital (A/D) converter. A laser beam is coupled into a waveguide which has been fabricated on an electrooptical crystal such as a lithium niobate LiNbO.sub.3 crystal. Electrodes are placed relative to the waveguide to form an electrooptical prism and an analog signal is fed to the electrodes. A modulated laser beam passing through the electrooptical prism is deflected in the plane of the waveguide in proportion to the applied analog signal. The deflected beam is expanded in the y-direction by diffraction-spreading or by a beam-spreading lens and falls on a ribbon-fiber, coded detector array. The array effectively codes the analog signal, translating the position of the deflected beam into a coded digital word which is representative of the magnitude of the analog signal.

Abstract: A method and means for x-ray lithography which utilizes means for producing n a vacuum system a high-temperature plasma from which soft x-rays are emitted. The x-rays pass through a mask exposing an x-ray resist on a substrate to produce the desired pattern on the substrate. The x-ray spectrum has a significant energy in the 1-5 keV range. These x-rays pass through the support layer of the mask, stop in the pattern material (gold) of the mask or, where the pattern material is lacking, are absorbed adequately by the x-ray resist. Since there is very little energy above 5 keV, there is little if any substrate damage due to the x-rays.

Abstract: This disclosure is directed to a radioisotope photoelectric generator for producing electrical energy. The construction of the generator is similar to that of a well-known storage battery. The generator is composed of alternate layers of high-Z, (high atomic-number) and low-Z(low atomic number) material which are insulated by vacuum or other insulating material. Low-energy photons from a radioactive source interact predominantly with the high-Z material by the photoelectric process, ejecting photoelectrons whose energy extends up to the incident gamma-ray energy E. By selecting the high-Z material thickness to be less than one electron range (at energy E) and the low-Z material thickness to be more than one electron range, there is a net electron transfer from the high-Z plates to the low-Z plates because electrons are emitted predominantly from the high-Z plates and stop in the low-Z plates. After start-up, a potential difference will build up between the high-Z and low-Z plates.

Abstract: A surface acoustic wave (SAW) device formed by an unitary insulating, magostrictive ferrite, slab whose easy axis of magnetization is initially (prior to the application of a d.c. magnetic biasing field) perpendicular to the direction of SAW-wave propagation. For example, the easy axis of magnetization in a single-crystal lithium ferrite slab is the <111> axis. Therfore this axis is aligned perpendicular to the SAW wave propagation direction and parallel to the edges of the SAW device. Application of a dc magnetic field swings the magnetic moments such that they will be parallel with the SAW wave propagation. Materials useful in carrying out this invention are those which have (1) an easy axis of magnetization, (2) good insulator qualities and (3) the magnetostrictive property. A dc magnetic field is applied parallel with the SAW direction or perpendicular to the easy axis of the material in order to align the magnetic moments in the direction of the SAW wave propagation.

Abstract: Optical access and duplex couplers for multimode, fiber, data transmission ines. Access couplers are for use with multiterminal communication systems whereas duplex couplers allow a single fiber to be used for data transmission in both directions. Grooves of different depths and widths are etched into silicon along natural crystal planes to position fibers of different diameters and to provide reflective silvered surfaces. Optical communication signals pass through smaller-diameter transmission lines to larger lines. Light surrounding the smaller-diameter line from the larger line is reflected by the reflective surfaces. Thus, information may be received and added as desired.

Abstract: A single-mode optical fiber to a single-mode optical channel waveguide end-fire coupler. A single fiber held within a capillary tube and positioned by a micropositioner is adjusted for greatest light output and then secured by an epoxy to one end of a channel waveguide. The two elements are then secured in place in a slot in the capillary tube which prevents rotation of the waveguide relative to the single fiber.

Abstract: An optical fiber acoustical sensor for detecting sound waves in a fluid mum. An optical fiber coil through which a light beam is transmitted is placed in a fluid medium. A sound wave propagating through the fluid medium and incident on the optical fiber coil changes the index of refraction of the optical fiber at the area of incidence. The index change causes a phase shift in the transmitted light which is detectable to denote the presence of the sound wave.

Abstract: A four-part electro-optical switch for switching optical radiation from one aveguide to another. Parallel waveguides are embedded in the surface of a substrate and provided with separating ends for transmitting radiation through the waveguides. Curved electrodes on the outer side of each waveguide in cooperation with a central electrode and separate voltage sources change the electro-optic properties of the waveguide such that radiation may be switched from one waveguide to the other when the voltage source is in the "on" state.

Abstract: An iron-doped indium phosphide or gallium arsenide semiconductor laser. The emiconductor material is doped when formed by uniformly distributing transition metal ions such as iron throughout the semiconductor. The concentration of the iron ions is from about 1.times.10.sup.15 to about 1.times.10.sup.18 ions per cubic centimeter, but is limited only by the solubility of iron indium phosphide or gallium arsenide. It has been determined that the greater the concentration of ions, the easier the laser emission is obtained. At liquid helium temperature, the iron-doped semiconductor laser will operate at a wavelength near 3 microns.

Abstract: A chemical converter-heat exchanger formed by a plurality of rows of paral, horizontal channels in a housing through which an inflowing fluid is heated. Vertical columns of horizontal channels connect alternately with an inlet and outlet manifold and carry the fluid back and forth horizontally in vertical columns of horizontal channels so that the inflowing fluid is partially heated by the outflowing fluid. Means are provided so that the bottom face of the housing is heated by the sun which in turn heats the fluid as the fluid passes through the bottom channels in the housing. A plurality of units may be mounted together to increase the output.

Abstract: A bidirectional optical communication system which includes a transmission ine which directs radiation onto a reflective surface through which a smaller-diameter fiber is inserted. The smaller-diameter fiber directs radiation into the larger-diameter fiber for transmission away from the reflective surface simultaneous with radiation transmitted through the larger-diameter fiber toward the reflective surface. A reflective surface and small fiber may be at each end of the larger-diameter fiber for bidirectional operation.

Abstract: A Xenon Bromide (XeBr) excimer laser is made by electron beam excitation over a range of from 10-3000 torr xenon with 0.5-4% Br.sub.2. Xe* generated by a high-energy electron beam reacts with Br.sub.2 to produce XeBr* which undergoes a bound-free transition resulting in stimulated emission on the transition XeBr*.fwdarw.Xe + Br + hv (230-360 nm) where* represents a low lying electronically excited state.