16 results about "Gamma ray detectors" patented technology

The invention relates to the technical field of nondestructive testing of element content and uniformity of fuel elements, and provides a fuel element detection method and system based on neutron imaging and activation analysis. The detection method comprises the following steps: S1, installing a to-be-detected sample, and adjusting an imaging collimation hole to be aligned with a neutron beam current of a neutron source; s2, the thermal neutrons are collimated by the imaging collimation hole and then transmit the to-be-detected sample, and spatial distribution of uranium and poison elements of the to-be-detected sample is obtained through detection of a neutron imaging detector; s3, selecting a specific target area, switching the activation analysis collimation hole to align to a neutron beam of the neutron source, and adjusting the position of the to-be-detected sample, so that the specific target area aligns to the neutron beam of the neutron source; thermal neutrons bombard a specific target area after being collimated by the activation collimation hole, and are received by the gamma ray detector so as to analyze and obtain the element content of the specific target area. According to the method, distribution and content of uranium and toxic elements in the fuel element can be rapidly and accurately determined on the premise of nondestructive testing.

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.

The invention discloses a single-layer Compton camera system and an imaging method, and relates to the technical field of nuclear radiation imaging. The system comprises a single-plane pixel type gamma ray detector used for collecting gamma ray interaction event data, including time information and energy information of each interaction and two-dimensional position information in a detector plane, and forming pixel counting distribution; the shielding structure is arranged on one side of the plane of the detector, is located in a local area of the detector and is used for enabling pixel counting distribution to generate a local counting missing feature when gamma rays are incident from one side where the shielding structure is located; and the judging and imaging module is used for judging a gamma ray incident side based on the local counting missing feature and executing Compton imaging reconstruction in a corresponding hemispherical view field range according to the judged incident side. According to the invention, partitioned omnidirectional imaging can be carried out on the radioactive source under the condition that a detector does not need to act on depth information, and meanwhile, generation of mirror image artifacts is avoided.

To provide both good time-of-flight resolution and interaction depth information. [Solution] The positron emission tomography apparatus according to the embodiment comprises a scintillation array and a photosensor array. The scintillation array includes a plurality of scintillator crystal units individually separated by a reflective material, and each scintillator crystal unit is configured to generate scintillation light in response to gamma-ray interactions within the scintillator crystal unit caused by gamma-ray irradiation from a subject, and has a substructure for decoding two or more depths within the scintillator crystal unit such that gamma-ray interactions at different depths cause scintillation light to escape from the photo-escape plane of the scintillator crystal unit in different patterns. The photosensor array converts the scintillation light received from the scintillation array into an electrical signal.

The invention relates to the technical field of radiation detection, in particular to a gamma ray detector and a gamma ray detection system. The detector comprises a substrate, a shading shell, a scintillation crystal, a silicon photomultiplier tube array, a first reflecting layer and a second reflecting layer, the shading shell is connected with the substrate so as to define an open inner cavity with the substrate; the scintillation crystal is located in the open inner cavity; the silicon photomultiplier tube array is located in the open inner cavity and is coupled with the scintillation crystal through an adhesive, and the silicon photomultiplier tube array is connected with the substrate to obtain electric energy; the first reflecting layer is arranged around the scintillation crystal; and the second reflecting layer is connected with a cavity opening of the open inner cavity to form a sealing structure. The invention has the advantages of magnetic interference resistance, miniaturization and high counting rate.

A gamma ray measurement tool has a tubular shell, a gamma ray detector disposed in the tubular shell, and a shield disposed between the tubular shell and the gamma ray detector. The gamma ray detector has a scintillation crystal coupled to a photomultiplier tube, and the shield has a open window configured to allow gamma rays to pass through and reach the scintillation crystal. Further, the tubular shell has a first axis in the longitudinal direction, and the gamma ray detector has a second axis in the longitudinal direction, the first axis and the second axis do not coincide with each other, and a distance between the scintillation crystal and an inner surface of the tubular shell through the window is shorter than a distance between the scintillation crystal and a portion of the tubular shell covered by the shield.

The invention particularly relates to a combined detector for an online sipping device. The combined detector comprises a beta-ray detector, a gamma-ray detector and a signal processing system, the beta ray detector adopts a plastic scintillation chamber with a high beta / gamma response ratio; the gamma ray detector adopts a scintillation crystal; the signal processing system is configured to perform beta-gamma coincidence measurement on output signals of the beta-ray detector and the gamma-ray detector; the plastic scintillation chamber is adjacent to the scintillation crystal space, and the detection areas of the plastic scintillation chamber and the scintillation crystal space are at least partially overlapped so as to jointly detect the detected gas flowing through the plastic scintillation chamber. The invention further relates to a nuclear fuel assembly damage detection method which adopts the combined detector. According to the invention, comprehensive detection of beta and gamma rays of radioactive inert gas is realized, and efficient and sensitive measurement of beta rays in large-volume radioactive inert gas is realized, so that the efficiency and accuracy of gamma-beta coincidence measurement are improved.

The invention provides a ray deposition process Boolean operation-based X / gamma ray detector passive efficiency scale calculation method, which belongs to the technical field of nuclear radiation measurement, and comprises the following steps: dispersing a radioactive source into a plurality of point radioactive sources in space, and obtaining ray angle distribution; analyzing to obtain the passing distance of the ray in the shielding body; calculating to obtain a line absorption coefficient; calculating the attenuation proportion of the shielding body; acquiring a ray deposition process in the sensitive body to form a scattering point coordinate matrix; performing coordinate system transformation on the ray deposition process to obtain a scattering point model, and performing graphic Boolean intersection operation on the scattering point model and the sensitive body; calculating the intrinsic detection efficiency of the rays; and calculating the radioactive source detection efficiency according to the ray angle distribution, the attenuation ratio and the intrinsic detection efficiency. According to the technical scheme provided by the invention, rapid and accurate passive efficiency calibration can be carried out, and a reliable and efficient solving technology is provided for large-volume long-distance radioactive source calibration.

A first aspect of the invention relates to a system for the in-line preparation of a vitrifiable mixture having a target composition, the system comprising: - a unit for dispensing raw materials, which is able to provide a premix comprising cullet, preferably at least 20% by weight of cullet; - a conveyor which is able to move the premix; - a unit for the in-line measurement of the composition of the premix by neutron activation, the in-line measurement unit comprising: • at least one neutron emission source configured to irradiate all or part of said premix; • at least one gamma ray detector configured to detect the gamma rays emitted by the premix when it is irradiated by the neutron emission source; and • a digital processing device configured to calculate, from the signal of the gamma ray detector, the content of chemical elements present in the premix, and optionally configured to estimate the water content and / or the content of organic compounds in the premix; and - at least one means for adjusting the premix to obtain the vitrifiable mixture having the target composition. The invention also relates to a method for the in-line preparation of a vitrifiable mixture having a target composition.

The invention discloses a method for growing an MAPbBr3 single crystal through a mixed solvent and a gamma ray detector, and relates to the technical field of semiconductor material preparation and radiation detection.The method comprises the steps that a precursor solution is prepared through the mixed solvent of DMF and DMSO, and the low-defect-density and large-size MAPbBr3 single crystal is obtained through growth at the precisely-controlled heating rate through a temperature inversion crystallization technology; according to a gamma ray detector constructed based on the single crystal, a Bi / MAPbBr3 / Au asymmetric electrode structure is adopted, and surface polishing treatment and protection ring design are combined, so that dark current and noise are remarkably reduced; according to the method, the dissolution-crystallization thermodynamic and dynamic behaviors of MAPbBr3 are regulated and controlled through the DMF-DMSO mixed solvent, controllable growth of low-defect-density single crystals is achieved, and the high-performance room-temperature gamma ray detector is constructed in combination with surface defect repair and asymmetric electrode energy band engineering.

According to a first aspect, the invention relates to an online preparation system for a vitrifiable mixture of target composition, the system comprising: - a raw material distribution unit capable of supplying a premix comprising cullet, preferably at least 20% by mass of cullet; - a conveyor capable of moving the premix; - an online measurement unit for the composition of the premix by neutron activation, the online measurement unit comprising: • at least one neutron emission source configured to irradiate all or part of said premix; • at least one gamma ray detector configured to detect the gamma rays emitted by the premix when it is irradiated by the neutron emission source;and • a digital processing device configured to calculate, from the gamma ray detector signal, the chemical element content present in the premix, and optionally configured to estimate the water content and / or the organic compound content in the premix; and at least one means for adjusting the premix to obtain the vitrifiable mixture of target composition. The invention also relates to a method for preparing a vitrifiable mixture of target composition online. Figure 1.

A method for determining real-time thermal power of a nuclear reactor based on number of gamma rays counted comprising measuring a number of gamma-ray counts by a gamma-ray detector that is placed outside a biological shield at a primary cooling circuit of a fission nuclear power plant so that maintenance of the detector is possible during normal operation of the fission nuclear power plant, and determining, by a computing device in real-time, a thermal power of the fission nuclear power plant based on the number of gamma-ray counts measured by the gamma-ray detector.

A downhole tool is equipped with a neutron generator configured to emit neutrons into a geological formation. The downhole tool includes one or more neutron detectors configured to detect neutrons that return to the downhole tool upon interaction with the geological formation. The downhole tool further includes one or more gamma ray detectors configured to detect gamma rays from the geological formation, the gamma rays being formed when the neutrons are inelastically scattered by the geological formation. Formation density is determined using measurements from a detector combination of at least one of the one or more neutron detectors and at least one of the one or more gamma ray detectors. The first formation density determined using the first detector combination is used to compensate for the second formation density determined using the second detector combination.

The invention provides a four-quadrant gamma ray detector and a gamma ray orientation method, and the detector comprises four gamma ray detection units with the same structure, the four gamma ray detection units are arranged in a 2 * 2 array, and each detection unit works independently and is used for converting an incident gamma ray into an electric signal; and the data acquisition and processing system is used for controlling a data acquisition time sequence and executing conformity judgment and selection logic and gamma ray direction resolving. The invention has the advantages that direction sensitive detection is realized through the four-quadrant array structure, and compared with the traditional collimator scheme, the weight is reduced by more than 70%; conventional background measurement and transient event capture are taken into account in a four-channel composite acquisition mode; the orientation algorithm based on the relative intensity ratio does not need absolute calibration, and the on-orbit calibration complexity is reduced. Tests show that the 1 MeV gamma ray orientation precision is superior to 5 degrees (half angle), and the requirements of space science exploration tasks are met.

A gamma-ray measurement tool includes a tubular housing, a gamma-ray detector disposed within the tubular housing, and a shielding layer disposed between the tubular housing and the gamma-ray detector. The gamma-ray detector includes a scintillation crystal coupled to a photomultiplier tube, and the shielding layer has an open window that allows gamma rays to pass through and reach the scintillation crystal. Furthermore, the tubular housing has a first axis in a longitudinal direction, and the gamma-ray detector has a second axis in the longitudinal direction; the first and second axes are not coincident, and the distance between the scintillation crystal and the inner surface of the tubular housing via the window is shorter than the distance between the scintillation crystal and the portion of the tubular housing covered by the shielding layer.

The application relates to a linear array gamma ray detector for intraoperative tumor detection and a use method thereof, which comprises an exploration shell and a handle shell, N gamma ray detection units are arranged in a column and at equal intervals along the length direction in the exploration shell, and a gamma ray detection unit at a middle position is a position detection unit W; each gamma ray detection unit is matched with a collimator, the collimating direction is parallel to the axis direction of the handle shell, and the collimating direction of the collimator corresponding to the position detection unit W is coincident with the axis of the handle shell; a displacement sensor and an angle sensor are arranged in the handle shell, a plurality of indicator lamps are arranged on the exploration shell and correspond to the N gamma ray detection units, and the indicator lamps are used for indicating whether the corresponding gamma ray detection units have signal responses; the gamma ray detection units, the displacement sensor, the angle sensor and the indicator lamps are connected with a controller. The technical scheme has the advantages of simple structure, lightness, low cost and convenient use.