Abstract: A gamma camera plate incorporates scintillation crystal which is sufficiently thick to effectively capture high energy radiation. The crystal is provided on its light output side with an array of light path-modifying partitions which extend partly through its thickness. These partitions define individual light collimating cells which reduce the light spreading which would otherwise prevent effective use of the plate for low energy radiation.

Abstract: Wear resistant extruder screws and methods for their manufacture are provided. The extruder screws include a base alloy screw body having a plurality of flights, a major outer diameter and a minor inner diameter. Each of the flights includes a pair of flight sides disposed between the major outer diameter and the minor inner diameter. The flight sides and minor inner diameter define a root area proximate to their juncture. The preferred extruder screws of this invention include a bond coating layer having a thickness of about 1-10 mils disposed over a major portion of the extruder screw which includes the root area, and a wear resistant coating layer having a thickness of about 10-100 mils disposed over said bond coating layer. The wear resistant coating layer preferably has an ASTM G65 dry abrasion wear rating of less than 10 mm3/kilometer, or, in further embodiments, the bond coating layer has a coefficient of thermal expansion which is in between that of the wear resistant coating layer and the base alloy.

Abstract: Ceramic igniter compositions are provided that contain components of conductive material and insulating material, where the insulating material component includes a relatively high concentration of metal oxide. Ceramic igniters of the invention are particularly effective for high voltage use, including throughout the range of from about 187 to 264 volts.

Abstract: A gamma camera plate incorporates scintillation crystal which is sufficiently thick to effectively capture high energy radiation. The crystal is provided on its light output side with an array of light path-modifying partitions which extend partly through its thickness. These partitions define individual light collimating cells which reduce the light spreading which would otherwise prevent effective use of the plate for low energy radiation.

Abstract: A gamma camera scintillation crystal plate assembly and method that may be used for both PET (positron emission tomography) and SPECT (single photon emission computer tomography). The crystal plate assembly includes two or more crystals which are optically coupled and tuned so as to control the energy position of the photopeaks at an output surface of the plate assembly. The crystals are tuned by various means including varying the surface finishes and material selection.

Abstract: A system and method for depositing a CVD diamond coating on a non-planar surface of an object is provided. The system includes a deflector having a deflecting surface which resists diamond coating by the diamond forming reagents produced by the system and which is adapted to withstand the relatively high deposition temperatures is provided. The deflector is positioned substantially axially with an axis of the distribution head of the CVD engine. The deflector is preferably generally wedge-shaped or conical and coupled to a motor which is adapted to rotate the deflector at a relatively high speed. A mandrel may be positioned about or to one side of the deflector. The deflector is oriented with respect to the distribution head and the mandrel such that a jet exiting the distribution head is deflected by the deflector onto a surface of an object positioned on the mandrel. The object surface may be non-planar.

Abstract: A compact medical nuclear imaging device, which generates a medical image from gamma radiation, can be held stationary or moved to search a large area for locating a radioactive area of interest. The compact medical imaging device comprises a collimator having an array of collimating channels, a radiation collection module converting the gamma radiation to an electric signal, an electronic module for processing the electrical signal, and a display module for displaying a two-dimensional image of the radiation scene, all of which preferably are assembled together in a single, compact module of a size small enough to permit it to be held and maneuvered by a human operator.

Abstract: A method is set forth for making a diamond film coated wear part, including the following steps: providing a part; depositing a first layer of polycrystalline diamond film on the part with non-{100} crystallographic faceting; and depositing on the first layer a second layer of polycrystalline diamond film having {100} crystallographic faceting, the second layer having a thickness sufficient to overgrow the roughness of said surface of said first layer with a continuous film.

Abstract: A low energy radiation detector for wireline applications and the like is provided with a housing made of carbon fiber and eopxy binder composite which is relatively transparent to x-radiation, while also being optically opaque and providing an hermetic enclosure for a scintillation crystal disposed inside the housing. Also disclosed is a neutron detector having such a housing.

Abstract: It is found that calcining chromium oxide powders having a particle size component smaller than 10 microns reduces the volume proportion of smaller particles and increases the general uniformity of particle sizes in the distribution and the roundness of the particles.

Abstract: A scintillation detector having reduced temperature sensitivity is provided by having two circuits for temperature compensation. The two circuits may be a thermistor in parallel with both a resistive element and a switching element. The switching element can be various devices including a zener diode, a Schottky barrier diode or an MIM. The temperature compensation circuit may be included in the circuit of a photo-detector such as a photomultiplier tube.

Abstract: Alpha alumina abrasive grits which are particularly well-suited to medium to low pressure grinding applications wherein the grits comprise uniformly dispersed microvoids.

Abstract: A thermal neutron detector comprises an inorganic scintillation crystal, an inner sleeve on said scintillation crystal and including boron-10, and an outer lead sleeve on said inner sleeve for shielding gamma rays from the inner layer. The boron-10 may be carried in a resiliently compressible silicone cast on the crystal to form a sleeve which functions to mechanically support the crystal inside a detector casing. The resiliently compressible, thermal neutron absorbing layer may also be used in other applications as a thermal neutron shield.

Abstract: Ceramic igniters are provided that comprise two cold zones with an interposed hot zone, the hot zone having an electrical path length of from 0.51 cm to about 2 cm. Igniters of the invention can effectively diffuse power density throughout the igniter hot zone region, without producing isolated temperature gradients which can lead to premature igniter degradation and failure. The invention also provides new methods for forming ceramic igniters.

Abstract: The method of the present invention includes placing a solid dopant in or near the nozzle of a DC arc jet. According to one embodiment of the invention, the interior surface of an arc jet nozzle is coated with a layer of copper by brushing the surface with a copper brush. According to another embodiment of the invention, the interior surface of an arc jet nozzle is coated with a layer of copper by plating it with copper. According to another embodiment of the invention, a copper cylinder is placed inside an arc jet nozzle. Apparatus according to the invention include a DC arc jet with a solid dopant placed in or near the nozzle according to one of the methods described. Diamonds according to the invention are conductive diamonds formed by a plasma jet process where a solid dopant was placed in or near the nozzle according to one of the methods described.

Abstract: A process for coating a tungsten carbide base material substrate with CVD diamond film includes carburization and gas-assisted vaporization of cobalt from the surface with simultaneous recrystallization of surface grains of tungsten carbide to change their stoichiometry for improved adherence. Also disclosed is a WC—Co cutting tool having a relatively fine WC grain size and being coated with adherent CVD diamond.

Abstract: CMP processes and products employ aluminas comprising alpha alumina particles having a particle width of less than 50 nanometers and a surface area of at least 50 m2/gm.

Abstract: Coating a sol-gel alumina abrasive grit with a ceramic oxide reduces the surface area of the grit and allows the production of vitreous bonded products using low temperature vitreous bond materials without the production of black spots as a result of the incomplete combustion of organic components used in the production process.

Abstract: This invention relates to a process comprising the steps of: a) providing a fiber preform comprising a non-oxide ceramic fiber with at least one coating, the coating comprising a coating element selected from the group consisting of carbon, nitrogen, aluminum and titanium, and the fiber having a degradation temperature of between 1400° C. and 1450° C., b) impregnating the preform with a slurry comprising silicon carbide particles and between 0.1 wt % and 3 wt % added carbon c) providing a cover mix comprising: i) an alloy comprising a metallic infiltrant and the coating element, and ii) a resin, d) placing the cover mix on at least a portion of the surface of the porous silicon carbide body, e) heating the cover mix to a temperature between 1410° C. and 1450° C. to melt the alloy, and f) infiltrating the fiber preform with the melted alloy for a time period of between 15 minutes and 240 minutes, to produce a ceramic fiber reinforced ceramic composite.

Abstract: A polishing slurry, useful in optical or CMP applications, comprises a ceria with a BET surface area of at least 10 m2/gm. The slurry may be made by subjecting a commercial ceria slurry comprising agglomerates to a mechano-chemical treatment at a pH of from 9 to 11 using media that are low purity alpha alumina or zirconia. Preferred slurries maintain a positive surface charge at all pH values. CMP slurries preferably comprise in addition an anionic surfactant to aid in removal of surface residues.