Abstract: Various technologies pertaining to formation or treatment of a thallium bromide crystal to improve the operable lifespan of a device that incorporates the thallium bromide crystal are described herein. In exemplary embodiments, treatments including focused ion beam implantation, selective material removal, and buffer layer application are performed on a thallium bromide crystal to inhibit motion of dislocations toward a region at which an electrical contact is desirably installed. In other exemplary embodiments, a thallium bromide crystal is doped with impurities during formation that inhibit the motion of dislocations in the crystal. In still other exemplary embodiments, a thallium bromide crystal is formed by way of processes that inhibit dislocation formation during crystal growth or eliminate dislocations in an existing thallium bromide mass.

Abstract: A stabilized scintillator includes a compound corresponding to formula (2) or (3), or activated derivatives thereof: A2BB?xB?yX6??(2) A2BB?XxX?y??(3) wherein A and B are monovalent cations, B? is a trivalent cation, X is a halogen, x and y are molar percentages, x+y=1; B? is an aliovalent exchange cation that has a different valence than B?, X? is an aliovalent exchange anion that has a different valence than X. A method of preparing the stabilized scintillator is also disclosed.

Abstract: The various technologies presented herein relate to a tiled filter array that can be used in connection with performance of spatial sampling of optical signals. The filter array comprises filter tiles, wherein a first plurality of filter tiles are formed from a first material, the first material being configured such that only photons having wavelengths in a first wavelength band pass therethrough. A second plurality of filter tiles is formed from a second material, the second material being configured such that only photons having wavelengths in a second wavelength band pass therethrough. The first plurality of filter tiles and the second plurality of filter tiles can be interspersed to form the filter array comprising an alternating arrangement of first filter tiles and second filter tiles.

Abstract: The present invention relates to sorohalide compounds having formula A3B2X9, where A is an alkali metal, B is a rare earth metal, and X is a halogen. Optionally, the sorohalide includes a dopant D. Such undoped and doped sorohalides are useful as scintillation materials or phosphors for any number of uses, including for radiation detectors, solid-state light sources, gamma-ray spectroscopy, medical imaging, and drilling applications.

Abstract: Doped luminescent materials are provided for converting excited triplet states to radiative hybrid states. The doped materials may be used to conduct pulse shape discrimination (PSD) using luminescence generated by harvested excited triplet states. The doped materials may also be used to detect particles using spectral shape discrimination (SSD).

Abstract: We describe the preparation and characterization of two zinc hybrid luminescent structures based on the flexible and emissive linker molecule, trans-(4-R,4?-R?) stilbene, where R and R? are mono- or poly-coordinating groups, which retain their luminescence within these solid materials. For example, reaction of trans-4,4?-stilbenedicarboxylic acid and zinc nitrate in the solvent dimethylformamide (DMF) yielded a dense 2-D network featuring zinc in both octahedral and tetrahedral coordination environments connected by trans-stilbene links. Similar reaction in diethylformamide (DEF) at higher temperatures resulted in a porous, 3-D framework structure consisting of two interpenetrating cubic lattices, each featuring basic to zinc carboxylate vertices joined by trans-stilbene, analogous to the isoreticular MOF (IRMOF) series. We demonstrate that the optical properties of both embodiments correlate directly with the local ligand environments observed in the crystal structures.

Abstract: Doped luminescent materials are provided for converting excited triplet states to radiative hybrid states. The doped materials may be used to conduct pulse shape discrimination (PSD) using luminescence generated by harvested excited triplet states. The doped materials may also be used to detect particles using spectral shape discrimination (SSD).

Abstract: Lanthanide halide alloys have recently enabled scintillating gamma ray spectrometers comparable to room temperature semiconductors (<3% FWHM energy resolutions at 662 keV). However brittle fracture of these materials upon cooling hinders the growth of large volume crystals. Efforts to improve the strength through non-lanthanide alloy substitution, while preserving scintillation, have been demonstrated. Isovalent alloys having nominal compositions of comprising Al, Ga, Sc, Y, and In dopants as well as aliovalent alloys comprising Ca, Sr, Zr, Hf, Zn, and Pb dopants were prepared. All of these alloys exhibit bright fluorescence under UV excitation, with varying shifts in the spectral peaks and intensities relative to pure CeBr3. Further, these alloys scintillate when coupled to a photomultiplier tube (PMT) and exposed to 137Cs gamma rays.

Abstract: A ?-conjugated organic material for detecting ionizing radiation, and particularly for detecting low energy fission neutrons. The ?-conjugated materials comprise a class of organic materials whose members are intrinsic semiconducting materials. Included in this class are ?-conjugated polymers, polyaromatic hydrocarbon molecules, and quinolates. Because of their high resistivities (?109 ohm·cm), these ?-conjugated organic materials exhibit very low leakage currents. A device for detecting and measuring ionizing radiation can be made by applying an electric field to a layer of the ?-conjugated polymer material to measure electron/hole pair formation. A layer of the ?-conjugated polymer material can be made by conventional polymer fabrication methods and can be cast into sheets capable of covering large areas. These sheets of polymer radiation detector material can be deposited between flexible electrodes and rolled up to form a radiation detector occupying a small volume but having a large surface area.

Abstract: The present invention describes an apparatus useful for detecting neutrons, and particularly for detecting thermal neutrons, while remaining insensitive to gamma radiation. Neutrons are detected by direct measurement of current pulses produced by an interaction of the neutrons with hexagonal pyrolytic boron nitride.

Abstract: A radiation detector for detecting ionizing radiation. The detector includes a semiconductor having at least two sides. A bias electrode is formed on one side of the semiconductor. A signal electrode is formed on a side of the semiconductor and is used to detect the energy level of the ionizing radiation. A third electrode (the control electrode) is also formed on the semiconductor. The control electrode shares charges induced by the ionizing radiation with the signal electrode, shielding the signal electrode until the charge clouds are close to the signal electrode. The control electrode also alters the electric field within the semiconductor, such that the field guides the charge clouds toward the signal electrode when the clouds closely approach the signal electrode. As a result, signal loss due to trapped charge carriers (i.e., electrons or holes) is minimized, and low-energy tailing is virtually eliminated.

Abstract: Crystals of lithium tetraborate or alpha-barium borate had been found to be neutron detecting materials. The crystals are prepared using known crystal growing techniques, wherein the process does not include the common practice of using a fluxing agent, such as sodium oxide or sodium fluoride, to reduce the melting temperature of the crystalline compound. Crystals prepared by this method can be sliced into thin single or polycrystalline wafers, or ground to a powder and prepared as a sintered compact or a print paste, and then configured with appropriate electronic hardware, in order to function as neutron detectors.

Abstract: A radiation detector for detecting ionizing radiation. The detector includes a semiconductor having at least two sides. A bias electrode is formed on one side of the semiconductor. A signal electrode is formed on a side of the semiconductor and is used to detect the energy level of the ionizing radiation. A third electrode (the control electrode) is also formed on the semiconductor. The control electrode shares charges induced by the ionizing radiation with the signal electrode, shielding the signal electrode until the charge clouds are close to the signal electrode. The control electrode also alters the electric field within the semiconductor, such that the field guides the charge clouds toward the signal electrode when the clouds closely approach the signal electrode. As a result, signal loss due to trapped charge carriers (i.e., electrons or holes) is minimized, and low-energy tailing is virtually eliminated.

Abstract: A high-energy photon imaging system including an imaging head, a signal processor, a data acquisition system and an image processing computer. The imaging head includes a detector comprising a plurality of closely-packed detection modules. Each detection module comprises a plurality of detection elements mounted to a circuit carrier. The detection elements produce electrical pulses having amplitudes indicative of the magnitude of radiation absorbed by the detection elements. The circuit carrier includes channels for conditioning and processing the signals generated by corresponding detection elements and for preparing the processed signals for further processing by a signal processor. Each conditioning and processing channel stores the amplitudes of the detection element electrical pulses exceeding a predetermined threshold. The detection modules employ a fall-through circuit which automatically finds only those detection elements that have a stored pulse amplitude exceeding the threshold.

Abstract: A high-energy photon imaging system including an imaging head, a signal processor, a data acquisition system and an image processing computer. The imaging head includes a detector including a plurality of closely-packed detection modules. Each detection module includes a plurality of detection elements mounted to a circuit carrier. The detection elements produce electrical pulses having amplitudes indicative of the magnitude of radiation absorbed by the detection elements. The circuit carrier includes channels for conditioning and processing the signals generated by corresponding detection elements and for preparing the processed signals for further processing by a signal processor. Each conditioning and processing channel stores the amplitudes of the detection element electrical pulses exceeding a predetermined threshold. The detection modules employ a fall-through circuit which automatically finds only those detection elements that have a stored pulse amplitude exceeding the threshold.

Abstract: A high-energy photon imaging system including an imaging head, a signal processor, a data acquisition system and an image processing computer. The imaging head includes a detector including a plurality of closely-packed detection modules. Each detection module includes a plurality of detection elements mounted to a circuit carrier. The detection elements produce electrical pulses having amplitudes indicative of the magnitude of radiation absorbed by the detection elements.

Abstract: A high-energy photon imaging system including an imaging head, a signal processor, a data acquisition system and an image processing computer. The imaging head includes a detector comprising a plurality of closely-packed detection modules. Each detection module comprises a plurality of detection elements mounted to a circuit carrier. The detection elements produce electrical pulses having amplitudes indicative of the magnitude of radiation absorbed by the detection elements. The circuit carrier includes channels for conditioning and processing the signals generated by corresponding detection elements and for preparing the processed signals for further processing by a signal processor. Each conditioning and processing channel stores the amplitudes of the detection element electrical pulses exceeding a predetermined threshold. The detection modules employ a fall-through circuit which automatically finds only those detection elements that have a stored pulse amplitude exceeding the threshold.

Abstract: A radiation detector for detecting ionizing radiation. The detector includes a semiconductor having at least two sides. A bias electrode is formed on one side of the semiconductor. A signal electrode is formed on a side of the semiconductor and is used to detect the energy level of the ionizing radiation. A third electrode (the control electrode) is also formed on the semiconductor. The control electrode shares charges induced by the ionizing radiation with the signal electrode, shielding the signal electrode until the charge clouds are close to the signal electrode. The control electrode also alters the electric field within the semiconductor, such that the field guides the charge clouds toward the signal electrode when the clouds closely approach the signal electrode. As a result, signal loss due to trapped charge carriers (i.e., electrons or holes) is minimized, and low-energy tailing is virtually eliminated.

Abstract: A high-energy photon imaging system including an imaging head, a signal processor, a data acquisition system and an image processing computer. The imaging head includes a detector comprising a plurality of closely-packed detection modules. Each detection module comprises a plurality of detection elements mounted to a circuit carrier. The detection elements produce electrical pulses having amplitudes indicative of the magnitude of radiation absorbed by the detection elements. The circuit carrier includes channels for conditioning and processing the signals generated by corresponding detection elements and for preparing the processed signals for further processing by a signal processor. Each conditioning and processing channel stores the amplitudes of the detection element electrical pulses exceeding a predetermined threshold. The detection modules employ a fall-through circuit which automatically finds only those detection elements that have a stored pulse amplitude exceeding the threshold.

Abstract: A high-energy photon imaging system including an imaging head, a signal processor, a data acquisition system and an image processing computer. The imaging head includes a detector comprising a plurality of closely-packed detection modules. Each detection module comprises a plurality of detection elements mounted to a circuit carrier. The detection elements produce electrical pulses having amplitudes indicative of the magnitude of radiation absorbed by the detection elements. The circuit carrier includes channels for conditioning and processing the signals generated by corresponding detection elements and for preparing the processed signals for further processing by a signal processor. Each conditioning and processing channel stores the amplitudes of the detection element electrical pulses exceeding a predetermined threshold. The detection modules employ a fall-through circuit which automatically finds only those detection elements that have a stored pulse amplitude exceeding the threshold.