Sandia Corporation

National Technology & Engineering Solutions of Sandia, LLC

Sandia National Laboratories

F Patrick Doty

Pin Yang

Xiaowang Zhou

Mark D Allendorf

Blake A Simmons

Patrick L Feng

Ralph Henry Page

Warren Ruderman

Douglas A Chinn

Ilya Zwieback

Haoran Deng

Christina A Bauer

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.

Thallium bromide (TIBr) semiconductors and devices with extended life apparatus, methods, and system

A stabilized scintillator includes a compound corresponding to formula (2) or (3), or activated derivatives thereof:ABB'B&#x2033;X&#x2003;&#x2003;(2)ABB&#x2032;XX&#x2032;&#x2003;&#x2003;(3)wherein A and B are monovalent cations, B&#x2032; is a trivalent cation, X is a halogen, x and y are molar percentages, x+y=1; B&#x2033; is an aliovalent exchange cation that has a different valence than B&#x2032;, X&#x2032; is an aliovalent exchange anion that has a different valence than X. A method of preparing the stabilized scintillator is also disclosed.

Stabilized scintillator

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.

Filter arrays

The present invention relates to sorohalide compounds having formula ABX, 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.

Sorohalide scintillators, phosphors, and uses thereof

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).

Doped luminescent materials and particle discrimination using same

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&#x2032;) stilbene, where R and R&#x2032; are mono- or poly-coordinating groups, which retain their luminescence within these solid materials. For example, reaction of trans-4,4&#x2032;-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. We further demonstrate that these materials produce high luminescent response to proton radiation and high radiation tolerance relative to prior scintillators. These features can be used to create sophisticated scintillating detection sensors.

Hybrid metal organic scintillator materials system and particle detector

Lanthanide halide alloys have recently enabled scintillating gamma ray spectrometers comparable to room temperature semiconductors (&#x3c;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 CeBr. Further, these alloys scintillate when coupled to a photomultiplier tube (PMT) and exposed toCs gamma rays.

Fracture-resistant lanthanide scintillators

A &#x3c0;-conjugated organic material for detecting ionizing radiation, and particularly for detecting low energy fission neutrons. The &#x3c0;-conjugated materials comprise a class of organic materials whose members are intrinsic semiconducting materials. Included in this class are &#x3c0;-conjugated polymers, polyaromatic hydrocarbon molecules, and quinolates. Because of their high resistivities (&#x2267;10ohm&#xb7;cm), these &#x3c0;-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 &#x3c0;-conjugated polymer material to measure electron/hole pair formation. A layer of the &#x3c0;-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. The semiconducting polymer material can be easily fabricated in layers about 10 &#x3bc;m to 100 &#x3bc;m thick. These thin polymer layers and their associated electrodes can be stacked to form unique multi-layer detector arrangements that occupy small volume.

Organic materials and devices for detecting ionizing radiation

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.

Boron nitride solid state neutron detector

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.

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Livermore, CA, United States of America

F Patrick Doty