Patents by Inventor Charles L. Melcher
Charles L. Melcher has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 8598530Abstract: The present disclosure discloses, in one arrangement, a single crystalline chloride scintillator material having a composition of the formula A3MCl6, wherein A consists essentially of Cs and M consists essentially of Ce and Gd. In another arrangement, a chloride scintillator material is single-crystalline and has a composition of the formula AM2Cl7, wherein A consists essentially of Li, Na K, Rb, Cs or any combination thereof, and M consists essentially of Ce, Sc, Y, La, Lu, Gd, Pr, Tb, Yb, Nd or any combination thereof. Specific examples of these scintillator materials include single-crystalline Ce-doped KGd2Cl7 (KGd2(1-x)Ce2xCl7) and Ce-doped CsGd2Cl7(CsGd2(1-x)Ce2xCl7).Type: GrantFiled: May 2, 2011Date of Patent: December 3, 2013Assignees: Siemens Medical Solutions USA, Inc., University of Tennessee Research FoundationInventors: Mariya Zhuravleva, Kan Yang, Charles L. Melcher, Piotr Szupryczynski
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Patent number: 8278624Abstract: LSO scintillation crystals with improved scintillation and optical properties are achieved by controlled co-doping a LSO crystal melt with amounts of cerium and an additional codopant such as calcium or other divalent cations. Crystal growth atmosphere is optimized by controlling the amount of oxygen in the atmosphere. Zinc is added as an additional material to restabilize crystal growth where calcium co-dopant is added. The decay time of the scintillation crystal can be controlled by controlling the concentration of co-dopant added.Type: GrantFiled: August 21, 2007Date of Patent: October 2, 2012Assignees: Siemens Medical Solutions USA, Inc., University of Tennessee Research FoundationInventors: Merry A. Koschan, Charles L. Melcher, Piotr Szupryczynski, A. Andrew Carey
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Patent number: 8148697Abstract: A phoswich device for determining depth of interaction (DOI) includes a first scintillator having a first scintillation decay time characteristic, a second scintillator having a second scintillation decay time characteristic substantially equal to the first scintillation decay time, a photodetector coupled to the second scintillator, and a wavelength shifting layer coupled between the first scintillator and the second scintillator, wherein the wavelength shifting layer modifies the first scintillation decay time characteristic of the first scintillator to enable the photodetector to differentiate between the first decay time characteristic and the second decay time characteristic. The phoswich device is particularly applicable to positron emission tomography (PET) applications.Type: GrantFiled: September 29, 2009Date of Patent: April 3, 2012Assignee: Siemens Medical Solutions USA, Inc.Inventors: Florian Bauer, Lars A. Eriksson, Ronald Grazioso, Charles L. Melcher, Harold E. Rothfuss
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Patent number: 8115173Abstract: A phoswich device for determining depth of interaction (DOI) includes a wavelength shifting layer between first and second scintillators of different scintillation materials and having different decay time characteristics. The wavelength shifting layer allows a true phoswich device to be constructed where the emission wavelength of one scintillator is in the peak excitation band of the other scintillator, by shifting the scintillation light outside of this excitation band to prevent scintillation light of one scintillator from exciting a response in the other scintillator, thus enabling unique identification of the location of a gamma photon scintillation event. The phoswich device is particularly applicable to positron emission tomography (PET) applications.Type: GrantFiled: April 28, 2008Date of Patent: February 14, 2012Assignee: Siemens Medical Solutions USA, Inc.Inventors: Lars A. Eriksson, Charles L. Melcher, Ronald Grazioso
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Publication number: 20110272585Abstract: A halide scintillator material is disclosed. The material is single-crystalline and has a composition of the formula A3MBr6(1-x)Cl6x (such as Cs3CeBr6(1-x)Cl6x) or AM2Br7(1-x)Cl7x (such as CsCe2Br7(1-x)Cl7x), 0?x?1, wherein A consists essentially of Li, Na K, Rb, Cs or any combination thereof, and M consists essentially of Ce, Sc, Y, La, Lu, Gd, Pr, Tb, Yb, Nd or any combination thereof. Furthermore, a method of making halide scintillator materials of the above-mentioned compositions is disclosed. In one example, high-purity starting halides (such as CsBr, CeBr3, CsCl and CeCl3) are mixed and melted to synthesize a compound of the desired composition of the scintillator material. A single crystal of the scintillator material is then grown from the synthesized compound by the Bridgman method. The disclosed scintillator materials are suitable for making scintillation detectors used in applications such as medical imaging and homeland security.Type: ApplicationFiled: May 2, 2011Publication date: November 10, 2011Inventors: Kan Yang, Mariya Zhuravleva, Charles L. Melcher, Piotr Szupryczynski
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Publication number: 20110272586Abstract: The present disclosure discloses, in one arrangement, a single crystalline chloride scintillator material having a composition of the formula A3MCl6, wherein A consists essentially of Li, Na K, Rb, Cs or any combination thereof, and M consists essentially of Ce, Sc, Y, La, Lu, Gd, Pr, Tb, Yb, Nd or any combination thereof. In another arrangement, a chloride scintillator material is single-crystalline and has a composition of the formula AM2Cl7, wherein A consists essentially of Li, Na K, Rb, Cs or any combination thereof, and M consists essentially of Ce, Sc, Y, La, Lu, Gd, Pr, Tb, Yb, Nd or any combination thereof. Specific examples of these scintillator materials include single-crystalline Cs3CeCl6, CsCe2Cl7, Ce-doped KGd2Cl7 (KGd2(1-x)Ce2xCl7) and Ce-doped CsGd2Cl7 (CsGd2(1-x)Ce2xCl7). In a further arrangement, the Bridgman method can be used to grown single crystals of the chloride scintillator materials compounds synthesized from starting chlorides.Type: ApplicationFiled: May 2, 2011Publication date: November 10, 2011Inventors: Mariya Zhuravleva, Kan Yang, Charles L. Melcher, Piotr Szupryczynski
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Publication number: 20110260107Abstract: LSO scintillation crystals with improved scintillation and optical properties are achieved by controlled co-doping a LSO crystal melt with amounts of cerium and an additional codopant such as calcium or other divalent cations. Crystal growth atmosphere is optimized by controlling the amount of oxygen in the atmosphere. Zinc is added as an additional material to restabilize crystal growth where calcium co-dopant is added. The decay time of the scintillation crystal can be controlled by controlling the concentration of co-dopant added.Type: ApplicationFiled: August 21, 2007Publication date: October 27, 2011Inventors: Merry A. SPURRIER, Charles L. MELCHER, Piotr SZUPRYCZYNSKI, A. Andrew CAREY
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Publication number: 20100090114Abstract: A phoswich device for determining depth of interaction (DOI) includes a first scintillator having a first scintillation decay time characteristic, a second scintillator having a second scintillation decay time characteristic substantially equal to the first scintillation decay time, a photodetector coupled to the second scintillator, and a wavelength shifting layer coupled between the first scintillator and the second scintillator, wherein the wavelength shifting layer modifies the first scintillation decay time characteristic of the first scintillator to enable the photodetector to differentiate between the first decay time characteristic and the second decay time characteristic. The phoswich device is particularly applicable to positron emission tomography (PET) applications.Type: ApplicationFiled: September 29, 2009Publication date: April 15, 2010Applicant: Siemens Medical Solutions USA, Inc.Inventors: Florian Bauer, Lars A. Eriksson, Ronald Grazioso, Charles L. Melcher, Harold E. Rothfuss
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Publication number: 20100078595Abstract: Crystals with improved scintillation and optical properties are achieved by codoping with a trivalent dopant and a divalent and/or a monovalent dopant. Embodiments include codoping LSO, YSO, GSO crystals and LYSO, LGSO, and LYGSO crystals. Embodiments also include codoped crystals with a controlled monovalent or divalent:trivalent dopant ratio of from about 1:1 for increased light yield to about 4:1 for faster decay time.Type: ApplicationFiled: September 28, 2009Publication date: April 1, 2010Applicant: Siemens Medical Solutions USA, Inc.Inventors: Lars A. Eriksson, Merry A. Koschan, Charles L. Melcher, Harold E. Rothfuss
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Publication number: 20090121141Abstract: A phoswich device for determining depth of interaction (DOI) includes a wavelength shifting layer between first and second scintillators of different scintillation materials and having different decay time characteristics. The wavelength shifting layer allows a true phoswich device to be constructed where the emission wavelength of one scintillator is in the peak excitation band of the other scintillator, by shifting the scintillation light outside of this excitation band to prevent scintillation light of one scintillator from exciting a response in the other scintillator, thus enabling unique identification of the location of a gamma photon scintillation event. The phoswich device is particularly applicable to positron emission tomography (PET) applications.Type: ApplicationFiled: April 28, 2008Publication date: May 14, 2009Applicant: Siemens Medical Solutions USA, Inc.Inventors: Lars A. Eriksson, Charles L. Melcher, Ronald Grazioso
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Publication number: 20020144640Abstract: A method of improving the light yield of Oxyorthosilicate scintillation crystals, such as Lutetium Oxyorthosilicate, Yttrium Oxyorthosilicate, Lutetium Gadolinium Oxyorthosilicate or Lutetium Yttrium Oxyorthosilicate scintillation crystals. In accordance with the teachings of the preferred embodiment, the Oxyorthosilicate scintillation crystals are annealed in a atmosphere selected to be a reducing atmosphere or slightly oxidizing at a selected annealing temperature. In this regard, in the preferred embodiment, the Oxyorthosilicate scintillation crystals are heated in a furnace. During the annealing cycle, the temperature is ramped up from room temperature to the annealing temperature over a selected period of time. After a second selected period of time of sustaining the annealing temperature, the annealing temperature is then ramped down over for a selected period of time.Type: ApplicationFiled: April 6, 2001Publication date: October 10, 2002Inventors: Mark S. Andreaco, Merry A. Spurrier, Charles W. Williams, Charles L. Melcher
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Patent number: 6413311Abstract: A Cerium-Doped Lutetium Oxyorthosilicate scintillator boule having a graded decay time. The method for manufacturing an LSO:Ce crystal boule having a decay time gradient decreasing from the top end to the bottom end first includes the step selecting an iridium crucible. The crucible is selected based upon its diameter relative to the diameter defined by said crystal boule. The crucible is also selected based upon its volume relative to the volume of the crystal boule to be grown. A Cerium dopant (CeO2) is added to a mixture of Lutetium Oxide (Lu2O3) and Silicon Dioxide (SiO2). The composition is heated until melted to define a melt. A seed crystal is then placed in contact with the melt, is rotated, and slowly withdrawn, thereby yielding an LSO:Ce crystal boule defining a decay time gradient.Type: GrantFiled: February 28, 2001Date of Patent: July 2, 2002Assignee: CTI, Inc.Inventors: Charles L. Melcher, Ronald Nutt, Michael E. Casey
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Publication number: 20010008116Abstract: A Cerium-Doped Lutetium Oxyorthosilicate scintillator boule having a graded decay time. The method for manufacturing an LSO:Ce crystal boule having a decay time gradient decreasing from the top end to the bottom end first includes the step selecting an iridium crucible. The crucible is selected based upon its diameter relative to the diameter defined by said crystal boule. The crucible is also selected based upon its volume relative to the volume of the crystal boule to be grown. A Cerium dopant (CeO2) is added to a mixture of Lutetium Oxide (Lu2O3) and Silicon Dioxide (SiO2). The composition is heated until melted to define a melt. A seed crystal is then placed in contact with the melt, is rotated, and slowly withdrawn, thereby yielding an LSO:Ce crystal boule defining a decay time gradient.Type: ApplicationFiled: February 28, 2001Publication date: July 19, 2001Inventors: Charles L. Melcher, Ronald Nutt, Michael E. Casey
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Patent number: 5961714Abstract: A method for producing lutetium aluminum perovskite crystals includes heat aging the crystal melt and maintaining the interface between a crystal and the melt from which it is pulled substantially flat as the crystal is grown. In a Czochralski growth method, the rate of rotation of the crystal and its diameter are typically controllable to provide the flat interface as the crystal is pulled. Crystals produced by this method exhibit less variability in scintillation behavior which allows larger crystals to be produced from a boule making them particularly suitable for spectroscopic uses. Such crystals find uses in borehole logging tools.Type: GrantFiled: March 7, 1996Date of Patent: October 5, 1999Assignee: Schlumberger Technology CorporationInventors: Charles L. Melcher, Jeffrey S. Schweitzer
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Patent number: 5660627Abstract: A method for producing lutetium oxyorthosilicate crystals includes maintaining the interface between a crystal and the melt from which it is pulled substantially flat as the crystal is grown. In a Czochralski growth method, the rate of rotation of the crystal and its diameter are typically controllable to provide the flat interface as the crystal is pulled. Crystals produced by this method exhibit less variability in scintillation behavior so making them particularly suitable for spectroscopic uses. Such crystals find uses in borehole logging tools.Type: GrantFiled: October 27, 1994Date of Patent: August 26, 1997Assignee: Schlumberger Technology CorporationInventors: Ralph A. Manente, Frank Bruni, Charles L. Melcher, Carl A. Peterson, Jeffrey S. Schweitzer
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Patent number: 5264154Abstract: A single crystal scintillator and apparatus for prospecting underground strata using the scintillator is described. The single crystal scintillator is a cerium doped gadolinium silicate compound of the formula:Gd.sub.2-(x+y) Ln.sub.x Ce.sub.y SiO.sub.5wherein Ln is Sc, Tb, Lu, Dy, Ho, Er, Tm, or Yb; 0.03.ltoreq.x.ltoreq.1.9; and 0.001.ltoreq.y.ltoreq.0.2.Type: GrantFiled: March 11, 1993Date of Patent: November 23, 1993Assignee: Hitachi Chemical Co., Ltd.Inventors: Seikichi Akiyama, Hiroyuki Ishibashi, Takeshi Utsu, Charles L. Melcher, Jeffrey S. Schweitzer
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Patent number: 5025151Abstract: A scintillator for use as a gamma ray or like radiation detector is composed of a single crystal of cerium-activated lutetium oxyorthosilicate having the general formulation Ce.sub.2x Lu.sub.2(1-x) SiO.sub.5. In a borehole logging application, the detector is mounted in a logging sonde with a high energy neutron source, for movement through a borehole traversing earth formations. Gamma radiation from the surrounding formations is detected and analyzed to provide information concerning hydrocarbons in the formations.Type: GrantFiled: August 30, 1990Date of Patent: June 18, 1991Assignee: Schlumberger Technology CorporationInventor: Charles L. Melcher
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Patent number: 4958080Abstract: A scintillator for use as a gamma ray or like radiation detector is composed of a single crystal of cerium-activated lutetium oxyorthosilicate having the general formulation Ce.sub.2x Lu.sub.2(1-x) SiO.sub.5. In a borehole logging application, the detector is mounted in a logging sonde with a high energy neutron source, for movement through a borehole traversing earth formations. Gamma radiation from the surrounding formations is detected and analyzed to provide information concerning hydrocarbons in the formations.Type: GrantFiled: August 4, 1989Date of Patent: September 18, 1990Assignee: Schlumberger Technology CorporationInventor: Charles L. Melcher
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Patent number: 4883956Abstract: Improved borehold logging methods and apparatus for detecting and measuring photon and other radiation from earth formations. Such radiation may be, for example: natural; generated by a source and modified by interaction with formation constituents; produced during or immediately following interactions between neutron irradiation and formation constituents; or produced by decay of constituents rendered artificially radioactive by prior neutron activation. The radiation is detected by a scintillator and photomultiplier tube, the scintillator comprising one or more crystals containing gadolinium, for example gadolinium orthosilicate doped with cerium. Such a detector provides advantageous operating characteristics, including relatively high detection efficiency and energy resolution and the ability to operate in the borehold environment without special protection against contamination or temperature effects.Type: GrantFiled: February 2, 1988Date of Patent: November 28, 1989Assignee: Schlumberger Technology CorporationInventors: Charles L. Melcher, Ralph A. Manente, Jeffrey S. Schweitzer