Abstract: A method of removing an yttria-based core from a niobium-based part is described. In the method, the core is treated with an effective amount of a leaching composition. The leaching composition is based on nitric acid, or a combination of nitric acid and phosphoric acid. The core material is effectively removed from the niobium-based part, and the process of removing the core does not detrimentally affect the quality of the part. Related casting techniques for various niobium-based parts are also described.

Abstract: A method of manufacturing a detector array for an imaging system, the method comprising providing a pixelated scintillator having a plurality of lost molded pixels comprising a scintillator material adapted to detect radiation.

Abstract: An apparatus and method for fabricating a high performance reflective material for use on scintillator elements in a computed tomograph (CT) imaging device. Adjacent scintillator elements are separated by gaps filled with a reflective coating layer. In one embodiment, the reflective coating layer consists of a surface level coating layer, an adhesion layer, a metallic reflective layer, and a top layer consisting of either a barrier coating layer or a polymeric encapsulant, or both. In another embodiment, the metallic reflective coating layer is applied to the scintillator element via an electroless metal deposition process utilizing a reducing agent and a metal complex. The CT reflectors formed by either embodiment have improved light output, minimized cross talk, higher geometric efficiency, and decreased performance degradation as compared with current CT reflectors that utilize organic binders and titanium dioxide fillers is achieved.

Abstract: A conversion device for use in an imaging system is provided. The conversion device includes a first perforated plate portion forming a plurality of collimator channels separated by a plurality of thin collimator walls. A second perforated plate portion forming a plurality of scintillator channels separated by a plurality of thin scintillator walls is attached to the first perforated plate portion. A reflective coating is applied to the inside scintillator surface of the plurality of thin scintillator walls. A scintillator material is filled into the plurality of scintillator channels.

Abstract: In some aspects, a scintillator composition includes, prior to annealing, the composition (G1-x-yAxREy)aDzO12, wherein D is selected from the group consisting of Al, Ga and In, G is selected from the group consisting of Tb, Y, La, Gd, and Yb, A is selected from the group consisting of Lu, Y, La, Gd, and Yb, and RE is selected from the group consisting of Ho, Er, Tm and Ce, and x is in the range from 0 up to about 0.2774, inclusive, y is in the range from about 0.001 up to about 0.012, inclusive, a is in the range 2.884 up to about 3.032, inclusive, and z is in the range from about 4.968 up to about 5.116, inclusive.

Abstract: Hafnium oxide HfO2 scintillator compositions are doped with titanium oxide and at least an oxide of a metal selected from the group consisting of Be, Mg, and Li. The scintillator compositions can include sintering aid material such as scandium and/or tin and a rare earth metal and/or boron for improved transparency. The scintillators are characterized by high light output, reduced afterglow, short decay time, and high X-ray stopping power. The scintillators can be used as detector elements in X-ray CT systems.

Abstract: The present invention provides terbium or lutetium garnet x ray scintillators activated with a rare earth metal ion, such as cerium, and treated by annealing in a controlled atmosphere comprising a predetermined amount of oxygen for a predetermined time and temperature to reduce radiation damage that would otherwise occur when the scintillator material is exposed to high energy radiation, such as the type of radiation required to use the scintillator for medical radiographic imaging and the like. In an embodiment, a single crystal or a polycrystalline scintillator comprising the general formula (Tb1−xLuxCey)3Al5O12 (where 0<×≦0.5, and y is in the range from about 0.0005 to about 0.2, and annealed at 1400° C. to 1500° C. in a controlled atmosphere comprising 1×10−6 to 0.22 atm oxygen shows an increased resistance to radiation damage.

Abstract: A radiation detector includes: a scintillator which produces UV photons in response to receiving radiation from a radiation producing source; and, a wide bandgap semiconductor device sensitive to the UV photons produced by the scintillator. The semiconductor device produces an electric signal as a function of the amount of UV photons incident thereon. Preferably, the electric signal is then measure, recorded and/or otherwise analyzed.

Abstract: In some aspects, a scintillator composition includes, prior to annealing, the composition (G1-x-yAxREy)aDzO12, wherein D is selected from the group consisting of Al, Ga and In, G is selected from the group consisting of Th, Y, La, Gd, and Yb, A is selected from the group consisting of Lu, Y, La, Gd, and Yb, and RE is selected from the group consisting of Ho, Er, Tm and Ce, and x is in the range from 0 up to about 0.2774, inclusive, y is in the range from about 0.001 up to about 0.012, inclusive, a is in the range 2.884 up to about 3.032, inclusive, and z is in the range from about 4.968 up to about 5.116, inclusive.

Abstract: Hafnium oxide HfO2 scintillator compositions are doped with titanium oxide and at least an oxide of a metal selected from the group consisting of Be, Mg, and Li. The scintillator compositions can include sintering aid material such as scandium and/or tin and a rare earth metal and/or boron for improved transparency. The scintillators are characterized by high light output, reduced afterglow, short decay time, and high X-ray stopping power. The scintillators can be used as detector elements in X-ray CT systems.

Abstract: The present invention provides terbium or lutetium garnet x ray scintillators activated with a rare earth metal ion, such as cerium, and treated by annealing in a controlled atmosphere comprising a predetermined amount of oxygen for a predetermined time and temperature to reduce radiation damage that would otherwise occur when the scintillator material is exposed to high energy radiation, such as the type of radiation required to use the scintillator for medical radiographic imaging and the like. In an embodiment, a single crystal or a polycrystalline scintillator comprising the general formula (Tb1−xLuxCey)3Al5O12 (where 0<x≦0.5, and y is in the range from about 0.0005 to about 0.2, and annealed at 1400° C. to 1500° C. in a controlled atmosphere comprising 1×10−6 to 0.22 atm oxygen shows an increased resistance to radiation damage.

Abstract: Scintillator compositions useful for the detection of high-energy radiation, such as X, &bgr;, or &ggr; radiation, contain alkali and rare earth pyrotungstates. In particular, the pyrotungstate is a double tungstate containing an oxide of an alkali metal selected from the group consisting of Na, K, Rb, and Cs and an oxide of a rare-earth element selected from the group consisting of Y, Gd, La, and Lu. The scintillators are characterized by high light output, reduced afterglow, short decay time, and high X-ray stopping power.

Abstract: A radiation detector includes: a scintillator which produces UV photons in response to receiving radiation from a radiation producing source; and, a wide bandgap semiconductor device sensitive to the UV photons produced by the scintillator. The semiconductor device produces an electric signal as a function of the amount of UV photons incident thereon. Preferably, the electric signal is then measure, recorded and/or otherwise analyzed.

Abstract: An improved scintillator detector cell geometry for converting radiation to light with improved light collection is provided. Shaping the exit face of a scintillator to increase the surface area of the exit face results in a decrease in a fraction of angles that undergo total internal reflection within the scintillator. The scintillator has the advantage of preventing total internal reflection parallel, as well as perpendicular, to the detecting surface of a light collection device. Further, providing a specular reflector on a hemispherical dome portion of the radiation detecting surface of the scintillator results in reduced bounce-off the specular reflector before light contacts the scintillator-photodiode interface. Furthermore, implementing a convex shape when coated with the specular reflector increases the fraction of light directed toward the photodiode compared to a plane surface parallel to the photodiode.

Abstract: Scintillator compositions useful for the detection of high-energy radiation, such as X, &bgr;, or &ggr; radiation, contain alkali and rare earth pyrotungstates. In particular, the pyrotungstate is a double tungstate containing an oxide of an alkali metal selected from the group consisting of Na, K, Rb, and Cs and an oxide of a rare-earth element selected from the group consisting of Y, Gd, La, and Lu. The scintillators are characterized by high light output, reduced afterglow, short decay time, and high X-ray stopping power.