Methods Patents (Class 250/395)
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Patent number: 6953937Abstract: A pulse discrimination method for discriminating between pulses having a short decay period and a long decay period, may comprise: Detecting the pulse; integrating a rise portion of the pulse; integrating a decay portion of the pulse; and comparing the integrated rise portion of the pulse with the integrated decay portion of the pulse to distinguish between a pulse having a long decay period and a pulse having a short decay period.Type: GrantFiled: June 26, 2003Date of Patent: October 11, 2005Assignee: Battelle Energy Alliance, LLCInventors: Edward L. Reber, Rahmat Aryaeinejad, David F. Spencer
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Patent number: 6946652Abstract: An apparatus for accelerated weathering testing specimens including discharge lamps as a concentrated light source for accelerating the deterioration of color, composition and/or structure of test specimens. Improved control calibration structures and methods of operation are also included. The test module to monitor the weathering test process from an improved location, detecting irradiance in the manner in which the specimens are exposed to such irradiance. The test modules are mounted in a pocket formed within the door for the test chamber such that the sensitive electronics of the modules are not exposed to the harsh environment within the test chamber, resulting in an exceptionally stable signal.Type: GrantFiled: January 3, 2005Date of Patent: September 20, 2005Assignee: Atlas Materials Testing Technology, L.L.C.Inventors: Rajen Rathod, Richard D. Donato
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Patent number: 6879425Abstract: The invention relates to a device for determining and/or monitoring the density and/or the level (L) of a filling material in a container. A transmitting unit which emits radioactive radiation and a receiving unit which is arranged in such a way that it receives the radioactive radiation or the secondary radiation that is produced by the interaction of the radioactive radiation with the filling material are provided. A regulating/evaluating unit which determines the density and/or the level of the filling material in the container using the measuring data that is supplied by the receiving unit is also provided. The aim of the invention is to provide a device which enables the level or the density of a filling material in a container to be measured reliably. To this end, the receiving unit consists of individual detector units.Type: GrantFiled: August 23, 2001Date of Patent: April 12, 2005Assignee: Endress + Hauser GmbH + Co. KGInventors: Hartmut Damm, Joachim Neuhaus, Wolfgang Kämereit
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Patent number: 6872936Abstract: An apparatus for accelerated weathering testing specimens including discharge lamps as a concentrated light source for accelerating the deterioration of color, composition and/or structure of test specimens. Improved control calibration structures and methods of operation are also included. The test module to monitor the weathering test process from an improved location, detecting irradiance in the manner in which the specimens are exposed to such irradiance. The test modules are mounted in a pocket formed within the door for the test chamber such that the sensitive electronics of the modules are not exposed to the harsh environment within the test chamber, resulting in an exceptionally stable signal.Type: GrantFiled: January 21, 2004Date of Patent: March 29, 2005Assignee: Atlas Material Testing Technology, L.L.C.Inventors: Rajen Rathod, Richard D. Donato
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Publication number: 20040262530Abstract: A pulse discrimination method for discriminating between pulses having a short decay period and a long decay period, may comprise: Detecting the pulse; integrating a rise portion of the pulse; integrating a decay portion of the pulse; and comparing the integrated rise portion of the pulse with the integrated decay portion of the pulse to distinguish between a pulse having a long decay period and a pulse having a short decay period.Type: ApplicationFiled: June 26, 2003Publication date: December 30, 2004Inventors: Edward L. Reber, Rehmat Aryaeinejad, David F. Spencer
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Publication number: 20040222381Abstract: A method of quantitative positron emission analysis includes accounting for the loss of positron-electron annihilation events and quantitative inaccuracies in positron emission assays.Type: ApplicationFiled: May 7, 2003Publication date: November 11, 2004Applicant: GENERAL ELECTRIC COMPANYInventor: Dinko Eduardo Gonzalez Trotter
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Publication number: 20040206909Abstract: A radiation measurement device includes a radiation detector generating an analog signal containing pulse components, an A/D converter converting the analog signal into sampled data, an n-th power pulse discrimination unit calculating n-th power values of the sampled data to discriminate the pulse component, where n is two or more, and a pulse counter counting a number of the discriminated pulse components.Type: ApplicationFiled: May 13, 2004Publication date: October 21, 2004Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Mikio Izumi, Masafumi Yamada, Tatsuyuki Maekawa, Teruji Tarumi
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Patent number: 6806475Abstract: The invention provides improved methods and apparatus for investigating emissions from radioactive sources within an environment. In particular, the method deploys a collimated detector to scan the environment and obtain approximate position information on sources within that environment together with further investigations using a moveable shielding component which is moved relative to the field of view of the collimator. In an alternative technique, the collimator is moved in two different directions to achieve positional information using scanning.Type: GrantFiled: March 27, 2002Date of Patent: October 19, 2004Assignee: British Nuclear Fuels, PLCInventors: John Adrian Lightfoot, Karl Anthony Hughes
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Patent number: 6791093Abstract: The invention provides a technique for correcting gamma ray intensities detected to account for variation in attenuation effects with energy. The corrected intensity values enable more accurate isotopic analysis to be conducted and render such techniques applicable to low level emission cases. The technique is particularly useful in investigate waste materials with a gamma emitting content which needs to be determined. The attenuation is corrected for using a bi-modal function to account for the attenuation effects arising from low and high atomic mass components of the material in which the emitters are present.Type: GrantFiled: June 4, 2003Date of Patent: September 14, 2004Assignee: British Nuclear Fuels PLCInventors: John Thomas Caldwell, Stephanie Ann Jones, Matthew Robert Newell
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Patent number: 6753532Abstract: A method of detecting and suppressing extraneous radiation influences in radiometric measurements utilizes, in addition to the measurement channel that extends at least essentially over the entire usable pulse amplitude spectrum, at least one substitute channel that encompasses only a fractional range of the usable pulse amplitude spectrum. The measurement channel (MK) and substitute channel (EK) are calibrated in terms of the same variables, such as fill level or volume. A comparison between the measurement values, defined by the respective pulse rates of the measurement channel and substitute channel, is brought about in such a way that the value of the linkage varies significantly if extraneous radiation occurs.Type: GrantFiled: March 6, 2002Date of Patent: June 22, 2004Assignee: Berthold Technologies GmbH & Co. KGInventor: Manfred Pfleger
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Patent number: 6720562Abstract: An apparatus for accelerated weathering testing specimens including discharge lamps as a concentrated light source for accelerating the deterioration of color, composition and/or structure of test specimens. Improved control calibration structures and methods of operation are also included. The test module to monitor the weathering test process from an improved location, detecting irradiance in the manner in which the specimens are exposed to such irradiance. The test modules are mounted in a pocket formed within the door for the test chamber such that the sensitive electronics of the modules are not exposed to the harsh environment within the test chamber, resulting in an exceptionally stable signal.Type: GrantFiled: March 15, 2002Date of Patent: April 13, 2004Assignee: Atlas Material Testing Technology, L.L.C.Inventors: Rajen Rathod, Richard D. Donato
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Publication number: 20030213913Abstract: An apparatus and method for determining the total energy of a continuously under-sampled energy signal resulting from an annihilation event detected by a positron emission tomograph (PET) scanner. An annihilation event is detected by a scintillator crystal and photomultiplier tube, which produces an energy signal that is continuously under-sampled by an analog-to-digital converter. The start time of the energy signal is determined by a constant fraction discriminator and time-to-digital converter. The start time is used to calculate a new amplitude for each sample, from which the total energy can be calculated.Type: ApplicationFiled: January 28, 2002Publication date: November 20, 2003Applicant: CTI PET Systems, Inc.Inventors: J. Clifton Moyers, John W. Young, Mark Musrock
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Publication number: 20030205677Abstract: The invention provides a technique for correcting gamma ray intensities detected to account for variation in attenuation effects with energy. The corrected intensity values enable more accurate isotopic analysis to be conducted and render such techniques applicable to low level emission cases. The technique is particularly useful in investigate waste materials with a gamma emitting content which needs to be determined. The attenuation is corrected for using a bi-modal function to account for the attenuation effects arising from low and high atomic mass components of the material in which the emitters are present.Type: ApplicationFiled: June 4, 2003Publication date: November 6, 2003Applicant: British Nuclear Fuels PLCInventors: John Thomas Caldwell, Stephanie Ann Jones, Matthew Robert Newell
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Patent number: 6600161Abstract: A method of imaging by means of ionizing radiation in which a first measurement f1 is performed by integrating a detection signal generated by each detection cell of an ionizing radiation detector while simultaneously making a second measurement f2 by counting ionizing rays, and then an estimate of the flux is calculated, in particular by using the formula f=&agr;·f1+(1−&agr;)·f2 where &agr; is an increasing function over the range 0 to 1 of a first estimate fe of the flux f, which first estimate is established as a function of at least one of the first and second measurements f1 and f2.Type: GrantFiled: January 2, 2002Date of Patent: July 29, 2003Assignee: Biospace InstrumentsInventors: Pascal Desaute, Serge Maitrejean
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Publication number: 20030122084Abstract: A method of imaging by means of ionizing radiation in which a first measurement f1 is performed by integrating a detection signal generated by each detection cell of an ionizing radiation detector while simultaneously making a second measurement f2 by counting ionizing rays, and then an estimate of the flux is calculated, in particular by using the formulaType: ApplicationFiled: January 2, 2002Publication date: July 3, 2003Inventors: Pascal Desaute, Serge Maitrejean
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Publication number: 20030122078Abstract: A mobile measuring arrangement for the large-surface and highly accurate characterization of radiation fields, preferably in the exterior region, is provided which, according to the invention, is characterized in that a hovering and remote controllable platform is provided which, by means of a measuring probe as well as by means of at least one position receiver/antenna, measures and characterizes radiation fields in a highly accurate and large-surface manner.Type: ApplicationFiled: November 4, 2002Publication date: July 3, 2003Inventor: Torsten Fritzel
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Patent number: 6509701Abstract: The present invention may be used in the field of microelectronics, in medicine as well as in the production of lighting appliances. The method and the device of the present invention are used for increasing the brightness of optical radiation sources powered by low-voltage power supplies. The optical radiation is generated by emitting electrons and by exciting the radiation. The electrons are generated by emitting the same from the surface of a cathode, while the excitation of the radiation involves accelerating the electrons in the gaseous interval up to an energy exceeding the excitation energy of the radiating levels of the gas. To this end, a voltage is applied between the cathode and the anode, wherein said voltage does not exceed the ignition voltage of a self-maintained discharge. The device of the present invention comprises a chamber as well as electrodes having surfaces which are transparent to the radiation.Type: GrantFiled: February 5, 2001Date of Patent: January 21, 2003Inventors: Alexandr Tursunovich Rakhimov, Jury Alexandrovich Mankelevich, Vladimir Vitalievich Ivanov, Tatiyana Viktorovna Rakhimova, Nikolai Vladislavovich Suetin
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Publication number: 20020125439Abstract: The invention provides a technique for correcting gamma ray intensities detected to account for variation in attenuation effects with energy. The corrected intensity values enable more accurate isotopic analysis to be conducted and render such techniques applicable to low level emission cases. The technique is particularly useful in investigate waste materials with a gamma emitting content which needs to be determined. The attenuation is corrected for using a bi- modal function to account for the attenuation effects arising from low and high atomic mass components of the material in which the emitters are present.Type: ApplicationFiled: February 28, 2002Publication date: September 12, 2002Applicant: British Nuclear Fuels PLCInventors: John Thomas Caldwell, Stephanie Ann Jones, Matthew Robert Newell
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Patent number: 6448564Abstract: An apparatus, methods, and systems for assaying materials are disclosed using a combination of detectors that scan for areas of material non-uniformity, and assay the type and amount of radioactivity present in the material. Scanning detectors are provided to scan for non-uniform levels of radiation emanating from the material. If any non-uniformity is detected by the scanning detectors, the material non-uniformity is removed and handled with radioactive material protocols. The remaining material may then be subject to assay. If the material shows no signs of non-uniform radiation emission, the assay detectors are used to assay the material. If the concentration of any one or more radionuclides exceeds a predetermined limit, the assayed material is handled with radioactive material protocols.Type: GrantFiled: May 30, 2000Date of Patent: September 10, 2002Assignee: GTSD Sub IIIInventors: Alfred N. Johnson, Jeffrey W. Dickinson, John L. McGehee, David H. Weigle, Timothy B. Ramsey
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Publication number: 20020079460Abstract: A method of simply and quickly determining &agr;-ray releasing nuclides having long half-life without carrying out a chemical separation is provided.Type: ApplicationFiled: May 30, 2001Publication date: June 27, 2002Inventors: Yasuhiro Uezu, Tetsuo Hashimoto
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Patent number: 6407394Abstract: A procedure having the steps of: weighing a known volume container (4) in order to determine the average density of its content; positioning the container (4) upon a support (1); positioning on respective supports (5) two &ggr; ray detectors (6) set symmetrically to the container; causing vertical movement (F2) of the container, so that its main longitudinal axis coincides with the axis (I—I) connecting the two detectors (6); causing movement (F1) of the two detectors upon their respective supports in order to stop them in a first tentative position; causing movement (F1) of the two detectors in order to stop them in a second symmetrical position that proves to be suited to providing countings of the radiations that are an optimum; measuring the &ggr; radiation and calculating the geometric mean of the counting ratios of the two detectors, such a geometric mean being linked to the intensity (I) of the corresponding &ggr; radiation by a formula (1-2) from which the radiation intensity is calculated.Type: GrantFiled: October 7, 1999Date of Patent: June 18, 2002Assignee: ENEL S.p.A.Inventors: Enrico Borioli, Alessandra Cesana, Giancarlo Sandrelli, Mario Terrani
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Patent number: 6369393Abstract: In a preferred embodiment, a method of digitally de-randomizing pulses in a radiation spectroscopy system, the method including the steps of: receiving an input signal representative of a radiation detector output; analyzing the input signal to derive separate event samples and background samples; storing the event samples and the background samples; and reading stored event samples and background samples and adjusting spacing in time between adjacent event samples such that the event samples are spaced apart a time interval at least equal to pulse processing time of elements receiving an output of spaced apart event samples and the background samples.Type: GrantFiled: October 2, 2000Date of Patent: April 9, 2002Assignee: Canberra Industries, Inc.Inventor: Valentin Jordanov
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Patent number: 6320193Abstract: An improved nuclear diagnostic method identifies a contained target material by measuring on-axis, mono-energetic uncollided particle radiation transmitted through a target material for two penetrating radiation beam energies, and applying specially developed algorithms to estimate a ratio of macroscopic neutron cross-sections for the uncollided particle radiation at the two energies, where the penetrating radiation is a neutron beam, or a ratio of linear attenuation coefficients for the uncollided particle radiation at the two energies, where the penetrating radiation is a gamma-ray beam. Alternatively, the measurements are used to derive a minimization formula based on the macroscopic neutron cross-sections for the uncollided particle radiation at the two neutron beam energies, or the linear attenuation coefficients for the uncollided particle radiation at the two gamma-ray beam energies.Type: GrantFiled: February 26, 1999Date of Patent: November 20, 2001Assignee: The United States of America as represented by the United States Department of EnergyInventors: John L. Morrison, Alan G. Stephens, S. Blaine Grover
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Patent number: 6215399Abstract: Zones of a passive infrared (PIR) motion detector lens are staggered at close range to provide for pet immunity. In a dual sensor, dual lens configuration, the sensor signal is acted on to generate an alarm only when the sensor signal is simultaneous, indicating that an infrared emitting object big enough to cross both staggered zones of a zone pair has been detected. To further enhance sensitivity and immunity to noise, two dual element PIR sensors are arranged in opposite polarity with their elements vertically parallel. The sensor output is simultaneous and of opposite polarity, and noise can be suppressed by blocking like-polarity signals.Type: GrantFiled: November 10, 1997Date of Patent: April 10, 2001Assignee: Shmuel HershkovitzInventor: Pinhas Shpater
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Patent number: 6160259Abstract: A method and apparatus for selectively integrating PMT channel signals in a gamma camera system are described. A trigger word is decoded to determine which of multiple PMT channels are affected by a given scintillation event. When two scintillation events overlap both spatially and temporally, only those channels which are affected by both events stop integrating in response to the second event. Pre-pulse pile-up is corrected by removing the tail of a preceding pulse from a current pulse using an approximation of the tail of the preceding pulse based upon the instantaneous energy of the current pulse and the current countrate. Extrapolation of the tail of the current pulse may also be performed in essentially the same manner.Type: GrantFiled: October 23, 1998Date of Patent: December 12, 2000Assignee: ADAC LaboratoriesInventors: Michael J. Petrillo, Donald R. Wellnitz, Thomas E. Scharf
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Patent number: 5933082Abstract: The device assists those who are visually handicapped and, in particular, warns blind or visually impaired travellers that they have entered a potentially dangerous area proximal to the edge of boarding platforms of the type typically found in public railway transit systems. An InfraRed Integrated Information System consists of an array of infrared transmitters and a portable detector/warning device to be held by the blind traveller. The transmitters create a beam of infrared light which bathes the section of the platform proximal to the platform edge. As the traveller moves into the region of the platform covered by the emission, the sensors in the warning device are activated and by audio, tactile or other stimuli alert the traveller of entry into the danger zone.Type: GrantFiled: April 2, 1996Date of Patent: August 3, 1999Assignee: The Johns Hopkins UniversityInventors: Joseph Lawrence Abita, John Sadowsky, Wolfger Schneider, Robert W. Massof
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Patent number: 5884234Abstract: The present invention is based on a digital pulse sampling and detection technique which samples a nuclear pulse train at a constant frequency asynchronously with the actual pulses, which occur at random times. The shape of pulses representative of the interaction of nuclear particles or gamma-rays with a nuclear detector is analyzed to determine the pulse length. Nuclear particles or gamma-rays are detected. A signal is formed containing pulses representative of the particles or gamma-rays. The pulses are sampled at a constant frequency to form a digital image of the pulse train. The pulse length is determined by counting the number of pulses with a first number of consecutive samples above a threshold and by counting the number of pulses with a second number of consecutive samples above the threshold. A ratio of the first and second number of consecutive samples is obtained. The ratio is used to adjust the pulse length.Type: GrantFiled: August 30, 1996Date of Patent: March 16, 1999Assignee: Schlumberger Technology CorporationInventors: Bruno Jorion, Christian Stoller
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Patent number: 5866907Abstract: An ultralow background multiphoton detectors device for radioisotopes has a background of about one count per day. Two opposed gamma and X-ray photon detectors each preferably include a scintillation crystal and a photomultiplier tube. Sandwiched between the detectors are a separator and a sample holder for a sample labelled with a radioisotope such as I.sup.125. The detectors convert emissions from the radioisotope into electric output pulses which are then subjected to signal processing for pulse shape analysis, discrimination of coincident from non-coincident events, and quantification of the radioisotope. Detector materials and components are selected to minimize background, and are shielded from external radiation. The device may further be constructed to resolve and provide images of two dimensional sample arrays.Type: GrantFiled: June 25, 1996Date of Patent: February 2, 1999Assignee: BioTraces, Inc.Inventors: Andrzej J. Drukier, Igor R. Sagdejev
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Patent number: 5859436Abstract: A germanium detector measures an energy spectrum of a gamma ray flux. The detector includes a cooling layer continuous over a periphery of the columnar germanium crystal. The cooling layer reduces current leakage induced by heat, so that high energy gamma rays can be precisely detected. A combination of a plurality of germanium crystal bodies connected one another to form the germanium crystal of at least 20 cm leads to a more precise detection of high energy gamma rays. A method for determining a photonuclear reaction cross section using the germanium detector enables measurement of the energy dependence of a photonuclear reaction cross section at high resolution. The method employs a white gamma ray flux radiated to a nuclide. The germanium detector measures the spectrum of a transmission gamma ray flux transmitted through the nuclide. Peaks are specified in the obtained spectrum. An atomic nucleus can be transformed using a monochromatic gamma ray flux having an energy level corresponding to the peak.Type: GrantFiled: August 18, 1997Date of Patent: January 12, 1999Assignee: Doryokuro Kakunenryo Kaithatsu JigyodanInventors: Hideo Harada, Isamu Sato
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Patent number: 5841142Abstract: Process and system for determining radiation exposure in airplanes The invention pertains to a process for the determination of the radiation load, respectively the dosage (effect) of the radiation prevailing in airplanes with the aid of an algorithm, with which the spectral composition of the encumbering radiation can be determined and which is subject to the altitude as well as the geographical, respectively the geomagnetic longitude and latitude, respectively, that the portions of the individual types of radiation of the locally total spectrum can be determined, or else have been determined.Type: GrantFiled: February 24, 1995Date of Patent: November 24, 1998Inventors: Klaus E. Duftschmid, Christian Schmitzer, Christian Strachotinsky
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Patent number: 5818337Abstract: A passive infrared intrusion detection device uses a dual element pyroelectric detector and a housing for surrounding and containing the dual element pyroelectric detector. The housing has a plurality of Fresnel lens elements for gathering infrared radiation from a "look down" volume of space and for focusing the gathered infrared radiation onto the pyroelectric detector. A mask positioned between the plurality of Fresnel lens elements and the detector partially occludes the gathered infrared radiation from the Fresnel lens elements to one of the elements of the dual element pyroelectric detector creating an imbalance in the signal thereby preventing common mode rejection.Type: GrantFiled: January 13, 1997Date of Patent: October 6, 1998Assignee: C & K Systems, Inc.Inventor: Fernando Erismann
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Patent number: 5814817Abstract: A process provides a cartography of an emission of radiation by a body (2) that is corrected with respect to the attenuation of radiation by the body. A radiation transmissions source (3) is able to assume several positions with respect to the body and emits photons toward the body. The process includes: for each position of the radiation source, determining a transmission measurement (N) of the photons emitted by the radiation source and transmitted by the body and determining an emission measurement projection of the photons emitted by the body, the transmission measurement and the emission measurement projection being performed with the same geometry of the body. Determining, for each position of the radiation source, an attenuation correction coefficient C of radiation due to the body in order to correct the emission measurement projection (E6); and then constructing an emissions map (E2) on the basis of the attenuation-corrected, emission measurement projections.Type: GrantFiled: May 3, 1996Date of Patent: September 29, 1998Assignee: Commissariat A L'Energie AtomiqueInventors: Regis Guillemaud, Pierre Grangeat
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Patent number: 5773821Abstract: Radiological surveys for the discovery and mapping of subterranean fossilized relics, notably dinosaur bones utilize a detector shielded by a lead casing having a collimating window oriented approximately parallel and slightly above ground surface to receive gamma radiation traveling approximately vertically upward.Type: GrantFiled: October 15, 1996Date of Patent: June 30, 1998Assignee: University of Utah Research FoundationInventor: Ramal D. Jones
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Patent number: 5646410Abstract: System and method for validating the signal for detecting a measuring chain with a wide band of nuclear radiations.This system for validating the signal of a measuring chain of nuclear radiations (1), includes a detector (10) able to deliver a wide spectral band signal to at least one processing unit (12, 14) and is characterized in that the system (30) includes means (32) for copying the detection system so as to deliver a copy of this signal to a calculation unit (34), the calculation unit (34) being able to calculate measuring spectral information representative of the spectrum of the detection signal and compare this information with reference spectral information. The system and method are applicable to chains for counting in fluctuations or pluses.Type: GrantFiled: April 18, 1996Date of Patent: July 8, 1997Assignee: Commissariat a l'Energie AtomiqueInventors: Eric Barat, Alain Bourgerette, Jean-Christophe Trama
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Patent number: 5646409Abstract: The instant invention relates to a method to compensate for extraneous radiation caused by the effects of intermittent active radiation sources (not effects due to cosmic or terrestrial radiation) that can cause errors in radiation measured values. For the purposes of suppressing these extraneous radiation effects in radio-active measuring methods, the commencement and termination of the extraneous radiation and the attainment of a stable condition in the extraneous radiation are determined. The difference between the measured value (before commencement of the extraneous radiation) and the measured value (on attainment of the stable condition) is determined. The measured value is then reduced by the determined difference for the duration of the extraneous radiation.Type: GrantFiled: March 6, 1996Date of Patent: July 8, 1997Assignee: Endress & Hauser GmbH & Co.Inventors: Ulrich Leisinger, Joachim Neuhaus
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Patent number: 5629525Abstract: A method determining the plutonium content of a material containing fluorine involves obtaining the mass ratio of plutonium in a compound comprising plutonium and fluorine, particularly plutonium tetrafluoride, to the total plutonium content. The method utilises a high resolution gamma ray spectrometry technique to obtain a count rate in a pair of gamma ray photopeaks. One of the photopeaks has an energy level of 414 keV, resulting from the decay of plutonium-239, and the other photopeak has an energy level of 583 keV, resulting from the decay of an excited sodium-22 nucleus following an (alpha,n) interaction with fluorine.Type: GrantFiled: August 2, 1994Date of Patent: May 13, 1997Assignee: British Nuclear Fuels PLCInventors: David J. Thornley, Christopher H. Orr, Christine A. Burnett
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Patent number: 5600307Abstract: A personal electromagnetic radiation monitor includes an electromagnetic radiation sensor assembly having a surface area sensor in the form of a conductive can-shaped or boss-like element. The surface area sensor detects the radial electric field component directly from the radiating antenna or a secondary radial field component created by the displacement current induced in the wearer of the personal monitor who is illuminated by the electromagnetic radiation. The radial field component is detected by a diode detector circuit and is provided to a comparator circuit which will trigger an alarm if the induced current exceeds a predetermined level.Type: GrantFiled: November 14, 1995Date of Patent: February 4, 1997Assignee: The Narda Microwave Corp.Inventor: Edward E. Aslan
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Patent number: 5574287Abstract: A non-zero feedback radiant flux reduces a radiant flux sensor's primary response excursion by keeping the total radiant flux on the sensor virtually constant. An increase in signal radiant flux is countered by a virtually equal decrease in feedback radiant flux. Reduced primary response excursion suppresses the effects of energy storage mechanisms within the sensor. Smaller response excursions decrease the sensor's response time and nonlinearity. Since many radiant flux feedback sources are virtually noiseless, radiant flux feedback does not degrade the sensor's Noise Figure.Type: GrantFiled: December 20, 1994Date of Patent: November 12, 1996Inventor: James A. Kuzdrall
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Patent number: 5545900Abstract: A radiation analysis apparatus is provided with circuitry for correcting errors in a pulse-height distribution due to differential non-linearities of the analog-to-digital converter that is employed for digitising the detector signals. Correction is performed by multiplying counts by correction factors so as to form corrected counts constituting a corrected pulse-height spectrum. Correction factors are obtained by supplying to the analog-to-digital converter a known control-measurement detector signal having a known corresponding ideal pulse-height spectrum. Comparison of the pulse-height spectrum actually formed upon supplying the control-measurement detector signal with the ideal pulse-height spectrum provides correction factors that are stored in a memory.Type: GrantFiled: March 22, 1994Date of Patent: August 13, 1996Assignee: U.S. Philips CorporationInventors: Hendrik J. J. Bolk, Georges C. P. Zieltjens
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Patent number: 5506415Abstract: A method and apparatus are provided for determining the number of photons in a single-mode, coherent microwave field. A plurality of Rydberg atoms are generated whereby each Rydberg atom has an energy state defined by a plurality of energy levels. The Rydberg atoms are passed through the microwave field one at a time. An exit state of the microwave field in terms of phase is measured as each Rydberg atom exits the microwave field. An exit energy level of each Rydberg atom exiting the microwave field is also detected. The number of Rydberg atoms exiting the microwave field in each of four measurement classes defined by the exit state and exit energy level are counted.Type: GrantFiled: December 20, 1994Date of Patent: April 9, 1996Inventors: Allen D. Parks, Kerry L. Beaver
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Patent number: 5465080Abstract: An infrared intrusion sensor includes an array of infrared detectors, infrared collection optics, a focal plane scanning device having a dither adapted to repetitively scan the infrared radiation across the detector array, signal process devices, and local or remote displays. The sensor incorporates heterodyne detection techniques with a local oscillator signal derived from the scanning frequency of the focal plane scanning device. The sensor has a low false alarm rate and enhanced detection range. A method of processing the signals includes analog to digital conversion, integration of the digital signals to produce a background signal, phase sensitive detection of the digital signal producing a target signal, and comparison of the background and target signals producing a difference signal. The difference signal is integrated to produce a background noise signal and processed to become a threshold signal which is finally compared to the difference signal to produce an alarm signal.Type: GrantFiled: September 7, 1994Date of Patent: November 7, 1995Assignee: The Commonwealth of AustraliaInventors: Kevin C. Liddiard, Brian W. Rice, Rodney J. Watson
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Patent number: 5430406Abstract: The circuit is adapted for integration of pulse signals of the shape U(t)=U.sub.0 exp(-t/.tau.), wherein the time constant .tau. can be determined in advance by a calibration measurement, in particular signals from a scintillation detector. The purpose is to treat pile-up phenomena, without measuring the integration time, wherein the measured integral is corrupted because the time distance between two pulses becomes smaller than the integration time for the first pulse. The circuit comprises an integrator (4, 5, 6, R, C) for the pulse signal and a summator (3, R.sub.1 -R.sub.3) for forming a weighted sum of the pulse signal (on 1, 2) and the integrated signal (from 4, 5), the weight of the pulse signal and the weight of the integrated signal having such a relation to each other that the result signal (on 8) is proportional to the sum of the time integral of the pulse signal and .tau. times the pulse signal.Type: GrantFiled: November 15, 1994Date of Patent: July 4, 1995Assignee: ADAC Laboratories, Inc.Inventor: Janusz Kolodziejczyk
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Patent number: 5416330Abstract: Radiation monitoring systems for crates and containers, and small volumes of foodstuff and tobacco, and whole body animal monitoring system for measuring the radiation contamination levels of containers, foodstuff, tobacco or animals and in the case of animals particularly, livestock utilized for meat consumption. The containers or animals are weighed, identified and then directed through a specially constructed shielded holding area, wherein multiple radiation detectors measure the radiation level for the containers or animal in the pen. A microprocessor analyzes the data information and provides a respective output for each container or animal which in turn is compared with predetermined standards and input information. The particular reading per container or each animal monitored actuates controls to segregate the containers or animals by those having acceptable and non-acceptable levels of radiation. The non-acceptable segregated containers or animals are specially held for evacuation and for disposal.Type: GrantFiled: November 18, 1992Date of Patent: May 16, 1995Assignee: Technology International IncorporatedInventors: Waleed H. Abul-Faraj, Abdul-Rahman A. F. Abdul-Fattah, Herman M. Daniel, Abdo A. Husseiny
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Patent number: 5412206Abstract: A method for determining the depth of a gamma emitting element beneath the surface of a volume of soil is disclosed. The disclosed method includes the steps of detecting gamma rays at a first height h.sub.1 above the surface; detecting gamma rays at a second height h.sub.2 above the surface; determining a ratio R representative of the ratio of the number of gamma rays detected at h.sub.2 to the number of gamma rays detected at h.sub.1, or vice versa; and inferring, on the basis of the ratio R, an estimate of the depth of the gamma emitting element beneath the surface.Type: GrantFiled: February 18, 1994Date of Patent: May 2, 1995Assignee: Westinghouse Electric CompanyInventors: John G. Seidel, Frank H. Ruddy, Joseph L. Gonzalez, Thomas V. Congedo
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Patent number: 5373284Abstract: A personal electromagnetic radiation monitor includes an electromagnetic radiation sensor in the form of at least one coil mounted on a rectangular form of lossy material. A first metal shield plate is situated adjacent to one side of the form on which the coil is mounted, and a second metal shield plate is situated on another side of the form. The metal shield plates have an impedance which varies substantially inversely proportional with the frequency of electromagnetic radiation sensed by the coil, and compensate for the variation in the magnitude of the induced current in the coil, which induced current, without at least one of the shields, would have varied in magnitude substantially directly proportional with the frequency of the electric field component of the electromagnetic radiation, so that the magnitude of an output signal generated by the sensor is relatively independent of the frequency of the sensed electromagnetic radiation.Type: GrantFiled: May 14, 1993Date of Patent: December 13, 1994Assignee: The Narda Microwave Corp.Inventor: Edward E. Aslan
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Patent number: 5373285Abstract: A personal electromagnetic radiation monitor includes an electromagnetic radiation sensor in the form of at least one coil mounted on a rectangular form of lossy material. A first metal shield plate is situated adjacent to one side of the form on which the coil is mounted, and a second metal shield plate is situated on another side of the form. The metal shield plates have an impedance which varies substantially inversely proportional with the frequency of electromagnetic radiation sensed by the coil, and compensate for the variation in the magnitude of the induced current in the coil, which induced current, without at least one of the shields, would have varied in magnitude substantially directly proportional with the frequency of the electric field component of the electromagnetic radiation, so that the magnitude of an output signal generated by the sensor is relatively independent of the frequency of the sensed electromagnetic radiation.Type: GrantFiled: October 12, 1993Date of Patent: December 13, 1994Assignee: The Narda Microwave Corp.Inventor: Edward E. Aslan
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Patent number: 5349195Abstract: The invention relates to a spectroscopy method for analysing high count rate pulses in an electrical signal s(t) emitted by a radiation detector. The method comprises analogically sampling the signal s(t) and integrating the sampled signal over a duration equal to the sampling period (T); converting the sampled signal into digital samples; detecting pulses on the basis of the digital filtered samples, and determining the energy spectrum from the detected pulses.The invention is applicable to detecting nuclear particles and radiation in well logging techniques.Type: GrantFiled: January 26, 1993Date of Patent: September 20, 1994Assignee: Schlumberger Technology CorporationInventor: Alain M. G. Dumont
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Patent number: 5340990Abstract: A multichannel analyzer incorporating the features of the present invention obtains the effect of fractional channels thus greatly reducing the number of actual channels necessary to record complex line spectra. This is accomplished by using an analog-to-digital converter in the asynscronous mode, i.e., the gate pulse from the pulse height-to-pulse width converter is not synchronized with the signal from a clock oscillator. This saves power and reduces the number of components required on the board to achieve the effect of radically expanding the number of channels without changing the circuit board.Type: GrantFiled: July 12, 1993Date of Patent: August 23, 1994Assignee: Battelle Memorial InstituteInventors: Larry W. Brackenbush, Gordon A. Anderson
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Patent number: 5319975Abstract: This invention provides for a fiber optic moisture sensor. The sensor is comprised of a housing and a support positioned within the housing. The support is coated with a film. A first and second light guides are positioned within the housing and communicate illumination to and from the film. A reflective surface is positioned within the housing facing the film. The film comprises an optically transparent polymer and a salt complex of a metal ion and an organic compound. The salt complex is capable of absorbing moisture and emits a fluorescence signal when excited by light at the appropriate wavelength. The fluorescence signal can be quenched when the salt complex absorbs moisture. An apparatus incorporating the sensor and a method of making the sensor are also provided.Type: GrantFiled: July 16, 1992Date of Patent: June 14, 1994Assignee: Rutgers, The State University of New JerseyInventors: Henrik Pederson, Ling Chu
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Patent number: 5304808Abstract: A method and apparatus for sampling radiation detector outputs and determining event data from the collected samples. The method uses high speed sampling of the detector output, the conversion of the samples to digital values, and the discrimination of the digital values so that digital values representing detected events are determined. The high speed sampling and digital conversion is performed by an A/D sampler that samples the detector output at a rate high enough to produce numerous digital samples for each detected event. The digital discrimination identifies those digital samples that are not representative of detected events. The sampling and discrimination also provides for temporary or permanent storage, either serially or in parallel, to a digital storage medium.Type: GrantFiled: February 8, 1993Date of Patent: April 19, 1994Assignee: The United States of America as represented by the United States Department of EnergyInventor: Daniel M. C. Odell