85 results about "Gamma photon" patented technology

The invention discloses a beta < + >-gamma-gamma coincidence positron annihilation lifetime-momentum correlation spectrometer, and belongs to the technical field of nuclear detection. The spectrometer comprises a positron annihilation life detection module, a positron annihilation gamma photon energy detection module, a signal acquisition module and a control and analysis module, and the positron annihilation life detection module is used for acquiring a life part in an AMOC spectrum; the positron annihilation gamma photon energy detection module is used for acquiring a momentum part in an AMOC spectrum by detecting gamma photons generated by positron annihilation; the signal acquisition module is used for acquiring signals generated by the positron annihilation life detection module and the positron annihilation gamma photon energy detection module; the control and analysis module is used for controlling the signal acquisition module and obtaining an AMOC spectrum based on signals acquired by the signal acquisition module. According to the method, the coincidence counting rate can be effectively improved, good coincidence time resolution and extremely low source components are achieved, and the construction cost of a spectrometer can be reduced.

The invention discloses a low-source component positron annihilation lifetime spectrometer for micron-sized film measurement, and relates to the field of positron annihilation lifetime. In the spectrometer, a positron annihilation lifetime measuring device is used for detecting gamma photons generated by decay of a radioactive source as initial detector signals; detecting gamma photons generated by annihilation of positron in the film sample as termination detector signals; the anticoincidence device is used for detecting anticoincidence signals generated when positron does not annihilate in the film sample; the positron annihilation life measuring device performs time coincidence judgment on a starting detector signal and a terminating detector signal of a case that positron annihilation occurs in a film sample according to the anti-coincidence signal, calculates a time difference between the starting detector signal and the terminating detector signal meeting a time condition, and counts the time difference. And drawing a positron annihilation lifetime spectrum. According to the invention, the source components in the positron annihilation lifetime spectrum are greatly reduced, and the measurement of the film sample by using a simple device is realized.

The invention relates to the technical field of neutron dose and internal pollution diagnosis, and provides a neutron dose and internal pollution diagnosis method and diagnostic agent.The method comprises the following steps that gamma ray signals are obtained at the head top and the lung of a human body through a detection device, and gamma rays are converted into electric pulse signals through the detection device; a digital multi-channel signal processing device is used for conducting signal processing on the electric pulse signals, signal processing comprises digital filtering and peak value sampling, and energy spectrum data are obtained; analyzing the energy spectrum data, and respectively obtaining a Na-24 characteristic gamma photon peak value at the top of the head of the human body and a characteristic gamma photon peak value at the lung of the human body; and according to the Na-24 characteristic gamma photon peak value obtained at the top of the head, calculating the neutron exposure dose according to a neutron dose algorithm, and according to the characteristic gamma photon peak value obtained at the lung, determining the type and activity of the internal pollution nuclide. According to the invention, accurate calculation of neutron dose and identification and activity determination of internal pollution nuclide are realized, and dual functions of neutron exposure dose and internal pollution diagnosis can be provided at the same time.

A positron emission tomography (PET) scanner may include a plurality of gamma radiation detector modules arranged to form a detector ring. Each detector module may include an array of elongated scintillation crystals. With respect to the detector ring, each elongated scintillation crystal includes a proximal end-face, two axially oriented lateral faces, two transaxially oriented lateral faces, and a distal end-face radially oriented into the detector ring to receive a gamma photon. An array of photosensors is positioned along a first of the axially oriented lateral faces of each elongated scintillation crystal to detect scintillation photons. A reflective material is positioned on the proximal end-face, the distal end-face, the transaxially oriented lateral faces, and a second of the axially oriented lateral faces of each elongated scintillation crystal to internally reflect scintillation photons. In various embodiments, a dual-channel processing circuit provides distinct timing and energy signals from the photosensors.

A positron emission tomography (PET) scanner includes multiple gamma radiation detector modules arranged to form a detector ring. Each detector module includes an array of elongated scintillation crystals. With respect to the detector ring, each elongated scintillation crystal includes a proximal end face, two axially-oriented side faces, two cross-axially-oriented side faces, and a distal end face oriented radially into the detector ring to receive gamma photons. An array of photosensors is disposed along a first of the axially-oriented side faces of each elongated scintillation crystal to detect scintillation photons. Reflective material is disposed on a second of the proximal end face, the distal end face, the cross-axially-oriented side face, and the axially-oriented side face of each elongated scintillation crystal to internally reflect scintillation photons. In various embodiments, a dual-channel processing circuit provides separate timing and energy signals from the photosensors.

This invention provides a cascaded imaging diagnostic and therapeutic integrated system, relating to the field of imaging. The system includes: a gantry, a slit collimator, a detector ring, and a base. The gantry is a hollow, regular prism. The slit collimator is mounted on the inner side wall of the gantry; the detector ring is mounted on the outer side wall of the gantry; the side wall of the gantry is mounted on the base. When a living organism to be detected is transferred into the cavity of the gantry, the detector ring images the target position within the organism through the slit collimator. The living organism carries a drug containing a nuclide that supports the emission of cascaded photons. The detector ring is connected to a host computer. This invention can collimate and detect "cascaded gamma photon pairs," thereby directly locating the nuclide decay position, achieving real-time imaging, short imaging time, and avoiding the defects of traditional nuclear medicine image reconstruction.

The present invention discloses a multi-nuclide imaging method based on image domain separation, comprising: obtaining the original data of multi-nuclide gamma photons; wherein the multi-nuclide includes a pure positron nuclide and several different impure positron nuclides; processing the original data of the multi-nuclide gamma photons using the three-coincidence technology to obtain a set of double-coincidence data and several sets of three-coincidence data of impure positron nuclides; performing low-dose imaging on the annihilation photon data in the three-coincidence data of several sets of impure positron nuclides respectively, and obtaining several corresponding impure positron nuclide distribution maps; performing image reconstruction on the double-coincidence data to obtain a mixed distribution map of multiple nuclides, and using the mixed distribution map to sequentially separate and process several impure positron nuclide distribution maps, and obtaining corresponding pure positron nuclide distribution maps. The defect that conventional PET cannot distinguish between pure positron nuclides and impure positron nuclides that produce instantaneous photons with a lower probability is solved.

The invention discloses a high-efficiency multichannel positron annihilation lifetime measurement method and device. The method comprises the following steps: 1) detecting instant gamma photons generated by positron of a target radioactive source and positron annihilation gamma photons by using a plurality of detectors, converting the instant gamma photons and the positron annihilation gamma photons into analog signals, and sending the analog signals to a sampling circuit; 2) a sampling circuit is responsible for sampling and digitally processing analog signals generated by each detector and then uploading the analog signals to an upper computer; and 3) the upper computer analyzes and processes the uploaded data to obtain the positron annihilation lifetime of the target radioactive source. The sampling circuit comprises a trigger module, a sampling module, a digital module and a control module. The control module configures each module according to a program issued by upper computer program control software. When the detector input signal meets the setting of the trigger module, the sampling module starts or stops sampling the detector signal of each channel; the digital module carries out digital processing on the signals, converts the signals into data and uploads the data to an upper computer.

The invention discloses a system and a method for improving the counting rate of a TOF-PET (time of flight-positron emission tomography) system. The system comprises a data processing module and a plurality of acquisition units, wherein each acquisition unit comprises a detector module and an electronics module; the detector module is used for detecting gamma photon pairs generated by positron annihilation in a detected object, converting nuclear signals generated according to the detected gamma photon pairs into electric signals and inputting the electric signals into the electronics module; the electronics module screens the input electric signals to obtain real coincidence cases and collects the real coincidence cases; the data processing module is used for taking the received two real coincidence cases in the same coincidence time window as a pair of real coincidence cases, and calculating the time difference between the two real coincidence cases in each pair of real coincidence cases and the corresponding detector module; and determining the position of the detected object according to the statistical result of the time difference of each pair of real coincidence cases. The theoretical effective counting rate can be increased by several times or even one magnitude, and the sensitivity of the system is greatly improved.

The invention relates to the technical field of space environment detection, in particular to a photoelectric sensor for gamma-ray spectrum measurement, which comprises a gamma-ray photon absorption transmission structure, a photoelectric conversion structure and an electric signal output structure, and is characterized in that the gamma-ray photon absorption transmission structure comprises a crystal sealing glass window, a crystal structure assembly and a crystal gland; the photoelectric conversion structure comprises a photoelectric tube first fixing ring, a photoelectric tube assembly, a photoelectric tube second fixing ring and a photoelectric tube gland; the electric signal output structure comprises an electric signal front-end processing board, a supporting column, a mounting base and a signal output lead. The overall structure of the sensor adopts upper, middle and lower three-position connection, so that the assembly precision and reliability of the whole machine are improved; seamless connection between the crystal and the photomultiplier tube is realized through a photoelectric coupling glue potting mode, and multiplication of gamma photon signals and photoelectric conversion efficiency are improved.

The invention relates to the technical field of nuclear, in particular to a device for detecting selenium content in fruits, which comprises a D-D neutron generator and a measuring chamber, the D-D neutron generator generates neutrons, the neutrons in the measuring chamber enter a sample to generate nuclear reaction with atomic nucleuses in the sample in the measuring chamber, and the neutrons in the measuring chamber are generated; after the atomic nucleus of the measuring chamber is activated, instant gamma rays and delayed gamma rays are released; the high-purity germanium detector in the measuring chamber receives delayed gamma rays of all elements in the sample in the measuring chamber and converts each gamma photon into an electric pulse signal; the multichannel analyzer is used for converting the electric pulse signals of the measuring chamber into digital signals, dividing channel addresses according to the size of the digital signals, counting the pulse number and forming a gamma ray energy spectrum; and the computer in the measuring chamber calculates the selenium content in the sample in the measuring chamber through the gamma ray energy spectrum in the measuring chamber. The method has the advantages of low detection limit, small error and high measurement result precision, and can quickly realize the detection of the selenium content in the fruits.

The invention discloses a low-source component positron annihilation lifetime spectrometer, and relates to the technical field of positron annihilation lifetime spectroscopy. In the spectrometer, a coincidence module is used for detecting accompanying gamma photons generated by positron as initial signals and detecting gamma photons generated by annihilation of the positron in a sample to be detected as termination signals; the anti-coincidence module is used for detecting a positron anti-coincidence signal generated by decay of a radioactive source; the data acquisition module is used for acquiring an initial signal, a termination signal and an anti-coincidence signal and transmitting the signals to the computer data processing module; and the computer data processing module is used for receiving and processing the signal data acquired by the data acquisition module to obtain the positron annihilation lifetime spectrum of the sample to be detected. The anti-coincidence module can well remove annihilation signals of positron in the thin plastic scintillator, so that a final positron annihilation lifetime spectrum only contains positron annihilation lifetime information of the sample to be detected.

A neutron flux detector comprising a source material and a solid state radiation detector is disclosed. The source material is configured to produce gamma photons greater than or equal to 6.8 MeV during neutron capture. The solid state radiation detector comprises a Schottky diode and an emitter layer comprising a Compton and photoelectron source material. The emitter layer is configured to receive the gamma photons produced by the source material. The emitter layer is spaced apart from the Schottky diode a distance such that a gap is defined between the emitter layer and the Schottky diode. The distance is selected such that only electrons produced by the emitter layer as a result of the emitter layer absorbing the gamma photons will contribute to a measured output signal of the Schottky diode.

Methods and apparatus for using exempt gamma photon sources to measure fluid properties are described herein. The gamma photon sources are used with detectors in an arrangement that provides a short photon path length between source and detector. Fluid measurement devices described herein have a fluid container defining an interior, an exempt gamma-ray source located outside the fluid container, and a gamma-ray detector located outside the fluid container, the exempt gamma photon source and the gamma-ray detector defining a photon path that traverses the interior of the fluid container along a non-diametric chord of the fluid container.

Reconstruction of simultaneous occurrence data of immediate gamma in PET scanning is provided. The invention discloses a method for identifying instant gamma rays through three-photon detection. The method involves using two annihilation photons and one immediate gamma photon to determine the direction of the corresponding immediate gamma ray.

The present invention provides a PET attenuation correction method and system for a five-modality integrated brain imaging device, relating to the field of brain imaging technology. The method comprises: generating a first attenuation coefficient map for a fixed-position hardware component; generating a second attenuation coefficient map for the optode and optical fiber of a non-fixed-position functional near-infrared spectrometer; superimposing the first attenuation coefficient map with the second attenuation coefficient map to generate a third attenuation coefficient map of the PET image under scanning conditions; and performing registration and attenuation correction on the third attenuation coefficient map to obtain an attenuation-corrected PET image. The present invention can more accurately obtain an attenuation template under each actual acquisition environment, and maximizes the correction of the effects of hardware components in the imaging field of view on the attenuation and scattering of gamma photons in PET imaging.

A neutron flux detector comprising a source material and a solid state radiation detector is disclosed. The source material is configured to produce gamma photons greater than or equal to 6.8 MeV during neutron capture. The solid state radiation detector comprises a Schottky diode and an emitter layer comprising a Compton and photoelectron source material. The emitter layer is configured to receive the gamma photons produced by the source material. The emitter layer is spaced apart from the Schottky diode a distance such that a gap is defined between the emitter layer and the Schottky diode. The distance is selected such that only electrons produced by the emitter layer as a result of the emitter layer absorbing the gamma photons will contribute to a measured output signal of the Schottky diode.

The invention discloses a positron annihilation coincidence Doppler broadening spectrometer based on beta +-gamma-gamma coincidence, which belongs to the technical field of nuclear detection and comprises a coincidence signal generation module, an annihilation gamma photon detection module, a signal acquisition module and a control and analysis module, the coincidence signal generation module is used for detecting positron generated by decay of the positron source and generating coincidence signals for case judgment and selection; the annihilation gamma photon detection module is used for detecting gamma photons generated by positron annihilation and generating pulse signals containing energy information; the signal acquisition module is used for acquiring coincidence signals and pulse signals; and the control and analysis module is used for controlling the signal acquisition module and acquiring a positron annihilation coincidence Doppler broadening spectrum from the acquired coincidence signal and the pulse signal. According to the positron annihilation coincidence Doppler broadening spectrometer, the extremely low source component proportion can be achieved, and then the accuracy of a test result is improved.

This disclosure provides a gamma camera with a collimation unit, applicable to the field of detection technology. The gamma camera includes at least one detection unit, comprising: a collimation unit comprising multiple needle-type collimator arrays arranged alternately, each needle-type collimator array comprising multiple arrayed needle-type collimators whose length directions point in the same direction, with the length directions of the needle-type collimators in different arrays pointing in different directions; multiple scintillation crystal units for detecting gamma photons penetrating the collimation unit along different directions, generating multiple sets of scintillation light signals; and multiple photoelectric conversion units, each coupled to a scintillation crystal unit, for converting the multiple sets of scintillation light signals into multiple sets of electrical signals for imaging by the gamma camera.

The application relates to an emission type computer tomography detector. The detector comprises a plurality of semiconductor wafers, a crystal array and a circuit board. Each semiconductor wafer is a silicon photomultiplier chip body, the crystal array comprises a plurality of regularly arranged crystals, one or more semiconductor wafers are arranged on each crystal, and the semiconductor wafer and the corresponding crystal are integrally packaged; the circuit board is arranged on one side of the crystal array, and each semiconductor wafer is electrically connected with the circuit board. The semiconductor wafer is integrally packaged with the crystal, i.e. the glass cover plate and the substrate can be cancelled, when the crystal receives gamma photons, the fluorescence emitted by the crystal can directly enter the semiconductor wafer without passing through the glass cover plate, thereby avoiding the loss of the fluorescence when the fluorescence passes through the glass cover plate and the silicon oil, so that the performance of the detector is improved.

The application discloses a method for imaging airtight inner cavity of an aero-engine by using a low-cost positron emission tomography device with good imaging quality, and the gamma photon detection mechanism of the positron emission tomography device comprises an embedded rotary flat plate detection device and a ring-shaped detection device; the ring-shaped detection device comprises a cylindrical mounting frame, and the inner wall of the cylindrical mounting frame is covered with second gamma photon detection crystals; the embedded rotary flat plate detection device comprises a mounting flat plate and a driving device for driving the mounting flat plate to rotate around the central axis of the ring-shaped detection device, and the mounting flat plate is provided with a plurality of first gamma photon detection crystals; the central angle of the cylindrical mounting frame corresponding to the first gamma photon detection crystals of the first detection crystal array is 60-90 degrees; and the diameter of the second detection crystal array is 1.6-2.6 times the distance between the first detection crystal array and the central axis of the ring-shaped detection device.

The application discloses a positron annihilation lifetime measurement device and method for thin film sample characterization, which is composed of a positron emitter, a positron detector and a gamma detector; a sample is placed between the positron emitter and the positron detector. The positron emitter contains a radioactive source and is responsible for detecting the positrons entering the sample, and the positron detector is responsible for detecting the positrons penetrating the sample. The gamma detector is responsible for detecting the 0.511 MeV gamma photons generated after the positrons are annihilated. The application can break through the limitation of measuring the sample thickness, is suitable for all types of positron radioactive sources, and sufficiently widens the experimental conditions; meanwhile, the non-contact measurement function can expand the application of the positron annihilation lifetime measurement method in the measurement of special samples and special environments.

The present invention provides a method and system for generating a mapping table of the interaction position between a crystal bar and gamma photons. By continuously mapping a crystal array with a point source or a general source, calculating the signals received by PMTs, and obtaining a scatter plot reflecting the interaction position of coincidence events. After removing the singular points in the two-dimensional position spectrum through digital processing, the local maximum algorithm is used for the two-dimensional position spectrum to estimate the center position of each crystal bar, and the data is binarized to obtain a binarized position map. The Euclidean distance from each pixel point to the nearest bright point is calculated for the binarized position map to obtain a distance distribution map. The local maximum values of the distance distribution map are obtained along the X direction and the Y direction respectively to divide the boundary positions of each crystal bar. In this way, each region corresponds one-to-one with the crystal bar array, and then the position mapping table of the system is determined. This method can cover all positions and there will be no divided dead zones.

A novel method is disclosed for obtaining transmission scan data in a PET scanner by incorporating one or more stationary gamma ray sources that provide forward scattered gamma photons that can be used as transmission imaging radiation.

The application provides a source device-based positron annihilation lifetime measurement system and method, which comprises a source chamber, a start gamma detector, a stop gamma detector and a positron detector. 22 The Na radioactive source is fixed on the surface of the source chamber, the source chamber and the positron detector are placed on the two sides of the thin film sample and are symmetrically opposite, and the positions are relatively fixed; the start gamma detector and the stop gamma detector are placed on the two sides of the positron detector and are responsible for detecting the 1.28 MeV gamma photons generated by the cascade when the positron is emitted by the radioactive source and the 0.511 MeV gamma photons generated after the positron annihilation. The application can effectively remove the noise positrons by improving the positron range on the non-sample side, reducing the detection efficiency of the far-end annihilation gamma photons, and reducing the size of the electronics; the positron annihilation position on the sample side can be accurately identified, the non-sample positron annihilation components can be excluded, the sample thickness limitation can be broken, and the thin film sample positron annihilation lifetime measurement can be realized.

The present disclosure provides a gamma detection system, including a detection module for receiving incident gamma photons and obtaining the position information, energy information, and count information M of the gamma photons; a processing module for statistically analyzing the gamma photons within a certain period of time to obtain their projection distribution data p, determining the energy E of the incident photons according to the energy spectrum statistically obtained, and thereby reading in the pre-stored left and right singular matrices V, UT, and diagonal matrix S, and determining the number N of singular values to be retained according to the count information M; a reconstruction module for processing the diagonal matrix S according to the number N of singular values to be retained, calculating the generalized inverse matrix C+ of the transfer matrix C of the detection module according to C+ = VS+UT, and calculating the reconstructed image according to f = C+p; and a display module for displaying the reconstructed image f, the energy spectrum of the incident gamma photons, and the count information M. The present disclosure can quickly realize gamma radiation reconstruction imaging with a small amount of calculation and is convenient for integration with small hardware circuits.

The invention relates to a gamma photon positioning method and device for an orthogonal strip-shaped tellurium-zinc-cadmium detector. The method comprises the following steps: acquiring current signals respectively generated by interaction of a plurality of gamma rays and the orthogonal strip-shaped tellurium-zinc-cadmium detector; vectorizing the plurality of current signals to obtain an input vector set; an initialized neural network is constructed based on the positions of a plurality of electrode strips in the orthogonal strip-shaped cadmium zinc telluride detector, and the number of initialized neurons is the same as that of the plurality of electrode strips; performing weight vectorization processing on the plurality of initialized neurons to construct an initialized weight vector set; and based on the input vector set and the initialized weight vector set, iteratively reducing the range of the initialized weight vector set through a self-organizing mapping algorithm to obtain a target weight vector, and determining the position of the gamma photon. The purpose of determining the position of the gamma photon based on the neural network and the self-organizing mapping algorithm is achieved, and therefore the technical effects of improving the accuracy of the position of the gamma photon and improving the position obtaining efficiency are achieved.

The embodiments of the present disclosure provide an imaging system, the imaging system may include a volume coil; a support assembly, wherein the volume coil is configured to surround an outer side of the support assembly or the support assembly is configured to surround an outer side of the volume coil; and a detector, installed on the support assembly and configured to receive gamma photons generated by radionuclides from a subject.

The invention provides a gamma camera based on a gas detector and a reconstruction method, the gamma camera comprises a gas time projection chamber detector and five groups of crystal energy meters, and the crystal energy meters are distributed on five side surfaces of the gas time projection chamber detector; after gamma incidence, Compton scattering occurs in working gas of the detector, particle tracks of scattered electrons are recorded by the detector, and the position of a Compton action vertex and the direction and energy of the scattered electrons can be reconstructed; the scattered photons are detected by a crystal energy meter on the side wall, the connecting line of the position detected by the crystal energy meter and a Compton action point is the direction of scattered photons, and energy collected by the crystal energy meter can reconstruct the momentum of the scattered photons; based on the momentum of scattered electrons and photons, the direction of incident gamma photons can be reconstructed. According to the gamma camera design, imaging information of five dimensions of three-dimensional position, time and energy is provided, and the imaging capability of the gamma camera is greatly improved.

The invention provides a detection imaging method and device for accurately obtaining the depth of gamma photons, and relates to the field of radiation detection.The method comprises the steps that after gamma rays enter a segmented scintillation crystal strip, the signal intensities of the two ends of the segmented scintillation crystal strip are obtained through the double-end reading technology, and a DOI factor is calculated based on the difference of the signal intensities of the two ends, a plurality of adjacent crystal sections in the scintillation crystal strip are designed into scintillation crystals with different decay time constants; a waveform discrimination technology is introduced, and a PSD factor is calculated according to output waveform differences of crystals at different decay times; and constructing a two-dimensional statistical graph according to the DOI factor and the PSD factor, carrying out classification discrimination on the gamma event through different areas in the two-dimensional statistical graph, determining a crystal segment where the gamma event occurs, and further obtaining the depth position of the crystal segment. According to the invention, the double-end reading technology and the waveform discrimination technology are combined, and the limit DOI resolution of the scintillation crystal detector can be further improved by comparing the difference between the signals at the two ends and combining the waveform characteristics of the signals.