144 results about "Neutron detection" patented technology

The invention discloses a sensor error compensation method based on a thermal expansion effect deformation model, and aims to solve the problem of measurement error increase caused by thermal expansion and cold contraction of a sensor in a high-temperature environment. The method comprises the following steps: firstly, carrying out multi-material thermal expansion parameter acquisition and modeling, and constructing a composite sensor structure and geometric parameters; secondly, designing a static compensation algorithm by using output calibration data of the sensor at different temperatures, and correcting output errors caused by the temperatures; finally, dynamic compensation and a self-adaptive correction mechanism are introduced in the actual operation process, and residual errors are corrected in real time. The method is suitable for a multi-sensitive-element composite sensor structure comprising a self-powered neutron detector and other auxiliary sensing elements, and the measurement precision and stability of the sensor under the high-temperature condition are improved in a mode of combining static calibration and dynamic compensation.

The invention discloses a neutron energy spectrum analysis method and device based on energy response and a medium, and relates to the technical field of neutron energy spectrum analysis, and the method comprises the steps: carrying out the particle transportation simulation of a neutron detector, and constructing a two-dimensional response matrix of a neutron injection energy interval and a detector output channel; carrying out discretization, fitting and energy segment compression on the response matrix to obtain an energy response matrix for spectrum inversion; sampling, shaping and normalizing an output signal of the detector, and constructing a measurement spectrum; the neutron energy spectrum is solved and evaluated by improving a spectrum inversion algorithm and combining multi-source spectrum parallel initialization and an adaptive step size structure. According to the invention, accurate characterization of the response characteristics of the detector is realized, the resolution and stability of spectrum inversion are improved, error accumulation and overfitting are inhibited, and the accuracy and reliability of neutron spectrum analysis are enhanced.

The invention provides a mountain freeze-thaw desertification early warning method and related equipment. The method comprises the following steps: acquiring thermal neutron intensity and epithermal neutron intensity of a target area; based on a target intensity ratio and a pre-obtained empirical fitting parameter set, target parameters are determined, and the target intensity ratio is the ratio of the thermal neutron intensity to the epithermal neutron intensity of the target area; determining a target moisture content according to the target parameter and the thermal neutron intensity or epithermal neutron intensity of the target area; and when the target moisture content is lower than a preset critical soil moisture threshold value, carrying out mountain freeze-thaw desertification early warning. Soil moisture is inverted through a cosmic ray neutron detection technology, environmental interference factors such as a non-soil water hydrogen source are corrected, local soil moisture of different vegetation types and soil types is accurately captured, freeze-thaw desertification is judged in combination with a critical soil moisture threshold, and early warning is given.

The invention belongs to the technical field of nuclear logging data processing, and particularly relates to a neutron detector pulse signal intelligent discrimination method and system based on deep learning, and the method comprises the following steps: collecting a pulse signal outputted by a detector, and when the rising edge of the pulse signal is detected to exceed a preset ground noise threshold value, determining the pulse signal; intercepting a time sequence containing the complete pulse signal, and carrying out normalization processing on the time sequence to obtain a normalized dimensionless voltage sequence; and calculating a first-order difference absolute value of adjacent sampling points in the dimensionless voltage sequence, and carrying out weighted calculation in combination with the time distance from the current sampling point to the peak moment to obtain a waveform oscillation entropy index representing the waveform microcosmic oscillation degree. According to the method, more than 98% of neutron tube ignition interference can be effectively eliminated, the high-energy part of the energy spectrum is remarkably purified, and the problem that data of the aged neutron tube are unavailable is solved.

The invention discloses a control method and device of a material moisture online monitoring system and a storage medium, and relates to the technical field of material moisture monitoring, and the method comprises the steps: starting a neutron generator assembly, and starting a neutron detector assembly and a gamma detector when the starting duration of the neutron generator assembly is greater than or equal to the preheating preset duration; based on a detection result of the neutron detector assembly, determining an accumulated scattering neutron share of the detected material, and obtaining a corresponding target hydrogen density matched with the accumulated scattering neutron share from a preset association library; based on a gamma detector, counting the monitored gamma rays in a classified manner according to the pulse amplitude, generating a gamma-ray energy spectrum, and extracting a water hydrogen characteristic peak area from the gamma-ray energy spectrum; according to the target hydrogen density, the water-hydrogen characteristic peak area and the energy spectrum calibration coefficient of the gamma-ray energy spectrum, the curing hydrogen ratio is determined; and determining the free water content of the detected material according to the cured hydrogen ratio. According to the invention, through dual-mode cooperative detection, the problem of low accuracy of moisture monitoring is solved.

The invention belongs to the technical field of nuclear power plant subcritical degree determination, and particularly relates to a method for determining a subcritical degree by adopting a spatial effect of an external neutron source. Comprising the following steps: 1, obtaining a curve of the ratio of the subcritical degree to near-source and passive neutron detector signals through theoretical calculation; 2, obtaining measurement values of four source range neutron detectors and four intermediate range neutron detectors; 3, calculating a near-source and passive ratio; and 4, according to the ratio calculated in the step 3, searching a ratio curve of the subcritical degree and the signals of the near-source and passive neutron detectors so as to obtain the reactivity of the reactor core. The method has the beneficial effect that the subcritical degree cannot be obtained by directly measuring through an instrument when the power level of the reactor is lower. According to the method, the subcriticality can be quickly obtained in a chart form through the ratio of the near-source neutron detector signals to the passive neutron detector signals or the ratio of the passive neutron detector signals to the near-source neutron detector signals.

The invention discloses a blended neutron / gamma discrimination polysiloxane scintillator and a preparation method thereof. The polysiloxane scintillator is composed of a matrix, a primary fluorescent dye, a secondary fluorescent dye and a cross-linking agent. A matrix of the scintillator is a copolymer of methyl phenyl polysiloxane and phenyl methyl siloxane, a main fluorescent dye is 2, 5-diphenyl oxazole (PPO), a secondary fluorescent dye is selected from 7-diethylamino-4-methylcoumarin (MDAC), and a cross-linking agent is 1, 3-divinyl-1, 3-diphenyl-1, 3-dimethyl siloxane. The obtained polysiloxane scintillator has good stability and can be used for neutron detection and neutron / gamma discrimination in a strong irradiation field environment.

The application discloses a double-gas-chamber neutron detector, belonging to the technical field of nuclear radiation detection and particle detection, comprising a gadolinium film neutron conversion layer, two time projection chamber (TPC) modules and an optional energy quantifier module. After capturing thermal neutrons, the gadolinium film generates multi-state particles, and the two TPC modules realize 4π solid angle neutron detection through electronic signal coincidence. The application replaces the scarce 3 He with gadolinium, combines the track reconstruction capability of the double TPC module, significantly improves the neutron detection efficiency and signal-to-noise ratio, and is suitable for nuclear reactor monitoring, industrial material analysis, agricultural moisture detection and deep space exploration and other fields. Through electronic-gamma coincidence measurement and mode recognition, high-precision neutron signal reconstruction and environmental background suppression are realized.

The invention provides a device and a method for on-line measurement of boron concentration in a boron trifluoride complex system, and relates to the technical field of boron-10 acid production. The device comprises a neutron emission part, a fluid circulation part, a neutron detection part and a data processing part. The neutron emission part is used for emitting thermal neutron beams, the fluid circulation part is communicated with a fluid pipeline at the bottom of an exchange rectifying tower of the boron trifluoride-anisole complex production process, and the fluid circulation part is of a neutron penetrable structure; the neutron detection part is arranged on the side, away from the neutron emission part, of the fluid circulation part and used for receiving thermal neutron beams penetrating through the boron trifluoride-anisole complex and converting neutron intensity signals into electric signals, and the data processing part is electrically connected with the neutron detection part and used for receiving the electric signals and sending the electric signals to the fluid circulation part. And inverting the concentration of boron-10 in the boron trifluoride-anisole complex according to the attenuation degree of the thermal neutron beam to obtain the total concentration of boron. The device can output the total boron concentration measurement result in real time, and sampling can be carried out without interrupting the production process.

A method of deploying a pulsed neutron logging tool. The method may comprise detecting natural gamma rays from the subterranean formation via one or more detectors of the pulsed neutron logging tool, broadcasting neutrons into the subterranean formation, and detecting neutron-induced gamma rays and natural gamma rays from the subterranean formation. The method may further comprise creating an inelastic spectrum, a capture spectrum, or a capture time decay from the natural gamma rays or the neutron-induced gamma rays, forming an inelastic yields, a capture elemental yields, or a formation sigma form the inelastic spectrum, the capture spectrum, or the capture time decay, creating a closure model from the inelastic yields and / or capture elemental yields and / or a formation sigma, and identifying a porosity, a mineral weight fraction, or a quality figure of merit from the closure model that quantifies geologic hydrogen reservoir quality.

The application discloses a same-position integrated double neutron detector, a logging instrument and an application method, and belongs to the field of uranium ore exploration logging. The double neutron detector comprises first and second scintillation crystals which are both sensitive to thermal neutrons and are arranged in a face-to-face manner, a photoelectric converter and a supporting portion; the first and second scintillation crystals and the photoelectric converter are arranged along the same axis to form a detection portion which is read out by a common light path, and the supporting portion is fixedly arranged outside the detection portion and supports the detection portion to be an integral component; a slow moderation layer is arranged on the outer wall surface of the first scintillation crystal except the bonding area; the logging instrument is provided with the double neutron detector, and the first and second scintillation crystals are calibrated in the same thermal neutron field during application; the spatial consistency error is eliminated through the same-position design of the double scintillation crystals; the hardware structure of the detector electronics is simplified through the common light path reading out design; and the detector module is convenient to integrate.

The invention provides a neutron detector availability evaluation method, system, equipment and medium, and relates to the technical field of nuclear power plant ex-core nuclear instrumentation system debugging and operation and maintenance, and the evaluation method comprises the steps: obtaining a high-pressure characteristic curve of a neutron detector in a current fuel cycle period; according to the high-pressure characteristic curve, acquiring the plateau inclination of the neutron detector in the current fuel circulation period; according to the high-voltage characteristic curve, the current power level of the reactor, the power level upper limit required to be measured by the neutron detector, the working voltage of the neutron detector and the voltage upper limit of the low-voltage area of the neutron detector, obtaining the voltage margin of the high-voltage characteristic curve of the neutron detector in the current fuel circulation period; and determining the availability of the neutron detector according to the plateau slope and the voltage margin of the high-voltage characteristic curve. According to the evaluation method, system, equipment and medium provided by the invention, the availability of the current neutron detector can be comprehensively evaluated and the residual service life of the neutron detector can be predicted on the premise of not changing out-of-core nuclear instrumentation system equipment.

The present disclosure provides a neutron detector and a neutron detection method. The neutron detector comprises an absorption layer and a photoelectric detection device, wherein: the absorption layer comprises at least one gamma sensitive layer and at least one neutron sensitive layer, the neutron sensitive layer is embedded in the first side of the gamma sensitive layer, wherein: the to-be-detected neutron and the gamma background of the to-be-detected neutron are incident from the second side of the gamma sensitive layer, the first side is opposite to the second side, the gamma background deposits energy in the gamma sensitive layer to generate first scintillation light, and the to-be-detected neutron deposits energy in the neutron sensitive layer to generate second scintillation light; the photoelectric detection device is arranged on the first side of the gamma sensitive layer embedded with the neutron sensitive layer, and is used for detecting the first scintillation light and the second scintillation light, so as to realize the detection and discrimination of the to-be-detected neutron and the gamma background. The method realizes the improvement of the discrimination effect of neutron events and gamma events.

The invention discloses a growth method of an organic-inorganic hybrid two-dimensional phenylethylamine lead bromide perovskite single crystal, relates to a growth method of a phenylethylamine lead bromide perovskite single crystal, and aims to solve the technical problems of long growth period and small thickness of the existing two-dimensional phenylethylamine lead bromide single crystal. The method comprises the following steps: 1, obtaining seed crystals; 2, thermodynamically regulating and controlling the solution supersaturation degree by a constant-temperature water bath device; 3, seed crystal growth is dynamically regulated and controlled through a seed crystal rotating-gradient cooling method under the solution rotating condition, the phenylethylamine lead bromide perovskite single crystal is obtained, the length and width of the phenylethylamine lead bromide perovskite single crystal are larger than 2 cm, the thickness of the phenylethylamine lead bromide perovskite single crystal is larger than 2 mm, fast neutron detection and high-energy nuclear particle screening can be met, and the phenylethylamine lead bromide perovskite single crystal is applied to the field of nuclear radiation detectors.

This invention provides a method, system, device, and medium for assessing the availability of a neutron detector, relating to the field of commissioning and maintenance technology for external nuclear instrumentation systems in nuclear power plants. The assessment method includes: obtaining the high-pressure characteristic curve of the neutron detector for the current fuel cycle; obtaining the plateau slope of the neutron detector for the current fuel cycle based on the high-pressure characteristic curve; obtaining the voltage margin of the high-pressure characteristic curve of the neutron detector for the current fuel cycle based on the high-pressure characteristic curve, the current power level of the reactor, the upper limit of the power level to be measured by the neutron detector, the operating voltage of the neutron detector, and the upper limit of the low-pressure region voltage of the neutron detector; and determining the availability of the neutron detector based on the plateau slope and the voltage margin of the high-pressure characteristic curve. The assessment method, system, device, and medium provided by this invention can comprehensively assess the current availability of the neutron detector and predict its remaining service life without changing the external nuclear instrumentation system equipment.

The invention relates to a detector array and a detection device for marking neutron beam imaging, a plurality of detector units in the array are arranged at intervals, a vacancy unit is arranged between every two adjacent detector units, each detector unit is a multi-pixel neutron detector with a scintillator array, and the scintillator array is arranged between the detector units. The scintillator array can realize n / gamma discrimination. Crosstalk of neutron signals among the scintillation units can be reduced, interference of background gamma signals can be effectively eliminated, the light collection capacity and the resolution capacity of edge points of the scintillator array can be improved through the special light guide structure design, and height adjustment and angle adjustment of the detector array can be achieved through the detector support.

This invention discloses a U-shaped neutron detection device for detecting the burn-up depth of spent fuel, belonging to the field of non-destructive testing technology for high-level radioactive spent fuel. It includes: two opposing arm detection components; a back detection component; each arm detection component includes: a moderator material; multiple arm He-3 counters spaced apart within the moderator material; a gamma shield disposed on the outer wall of the moderator material; and a cadmium sheet disposed on the outer wall of the other side of the moderator material; the back detection component includes: a support material, with both ends of the support material fixedly connected to the ends of the two moderator materials; multiple back He-3 counters spaced apart within the support material; a base plate disposed on the outer wall of the support material; and a cable connection assembly disposed on the side of the base plate away from the spent fuel component to be measured. This invention provides dual protection for the measurement of spent fuel burn-up depth by utilizing fission neutron information and transmitted neutron information, meeting the requirements for online detection.

This application discloses a control method, device, and storage medium for an online material moisture monitoring system, relating to the field of material moisture monitoring technology. The method includes: starting a neutron generator assembly; when the start-up time of the neutron generator assembly is greater than or equal to a preset preheating time, activating a neutron detector assembly and a gamma detector; determining the cumulative scattered neutron share of the measured material based on the detection results of the neutron detector assembly, and obtaining the cumulative scattered neutron share to match the corresponding target hydrogen density from a preset correlation library; generating a gamma spectrum based on the gamma rays monitored by the gamma detector according to pulse amplitude classification and counting, and extracting the water hydrogen characteristic peak area from the gamma spectrum; determining the solidified hydrogen ratio based on the target hydrogen density, the water hydrogen characteristic peak area, and the energy spectrum calibration coefficient of the gamma spectrum; and determining the free water content of the measured material based on the solidified hydrogen ratio. This application solves the problem of low accuracy in moisture monitoring through dual-modal collaborative detection.

The invention discloses a measuring rod and an over-drill-bit measurement-while-drilling device and method. The measuring rod is provided with at least three expansion jackets at intervals in the radial direction, and any two expansion jackets and at least one part of the underground side wall form a measuring cavity after expansion. A liquid injection hole is formed in the part, in the measuring cavity, of the measuring rod, and a liquid injection channel communicated with the liquid injection hole is formed in the measuring rod in the radial direction; the measuring rod is provided with a measuring cabin between two adjacent expansion jackets, and the measuring cabin is at least integrated with a pressure sensor and a neutron detection assembly; the pressure sensor is used for collecting the pressure in the measuring cavity; the neutron detection assembly is used for measuring stratum parameters in the measurement cavity in a pressurized state. The multiple expansion jackets are used for forming the measuring cavities with different lengths so as to eliminate sealing failure caused by irregular borehole diameters, or the multiple expansion jackets are used for forming the multiple spaced measuring cavities so as to reduce the trust risk of a single data source, and a pressure sensor, neutron detection and the like are used for measuring stratum data in a pressurized environment.

This invention discloses a neutron analysis physics testing system and method, belonging to the field of nuclear physics testing technology. The system includes: a high-speed synchronous pulse generator for generating pulse signals with multiple modulation sequences; an ultrashort pulse neutron generator for emitting short pulse neutron rays with specified parameters onto a sample; a neutron detector for acquiring secondary neutron signals; a gamma detector for acquiring characteristic gamma signals generated by neutron-excited probes of the sample; a safety control module for controlling the operating state of the ultrashort pulse neutron generator; and a data processing device for real-time collection and summarization of neutron signals and characteristic gamma signals based on the timing of the pulse signals with multiple modulation sequences. This system reduces time window drift and measurement errors, and activates the ultrashort pulse neutron generator only when a gate signal allows, improving the accuracy, safety, and stability of geological physics parameter measurements.

The application discloses a cooling flow passage blockage monitoring method and system based on a neutron noise signal, and a medium, relates to the technical field of cooling flow passage monitoring, and comprises the following steps: arranging a plurality of self-powered neutron detectors in a reactor, collecting neutron noise signal data measured by the self-powered neutron detectors, establishing a coolant flow distribution relationship based on the neutron noise signal data, obtaining a reactor core coolant flow distribution graph, and determining whether cooling flow passage blockage occurs according to the reactor core coolant flow distribution graph. The application solves the problem that the reactor core flow passage blockage anomaly cannot be monitored, avoids the local overheating of fuel assemblies caused by flow passage blockage, and effectively guarantees the safety and reliability of the reactor core.

The invention relates to the technical field of ionizing radiation measurement, and discloses a delayed neutron detector calibration device and method. The delayed neutron detector calibration device comprises a box body, a point neutron source and a moving assembly. An independent working cavity and an independent mounting cavity are defined by the box body. And the point neutron source is arranged in the mounting cavity. The moving assembly is arranged in the box body, the connecting end of the moving assembly extends into the working cavity, and the connecting end of the moving assembly is connected with the detector. Wherein the moving assembly is used for driving the detector to move relative to the point neutron source, so that different positions of the detector correspond to the point neutron source, and the reading of the detector is obtained so as to perform segmented calibration on the detector. According to the method and the device, the delayed neutron detector can be calibrated on site, the time of the calibration implementation process of the delayed neutron detector is shortened, and the difficulty of the calibration implementation process of the delayed neutron detector is reduced.

The application discloses a method for quickly obtaining a steady-state space electric field of an insulation layer of a self-powered detector, and comprises the following steps: obtaining radiation field information and detector information at a position where a self-powered neutron detector is located, and simulating to obtain an electric charge deposition amount generated by irradiation current in different radius intervals per unit time of the detector; according to the law of conservation of electric charge, estimating an electric charge loss amount generated by conduction current in different radius intervals of an insulator per unit time under a steady-state condition; combining Ohm's law to establish an expression of the electric charge loss amount generated by the conduction current about an electric field intensity under the steady-state condition, and combining a boundary condition to obtain an electric field intensity distribution, an electric charge density distribution and a potential distribution. The application can effectively improve the calculation efficiency and realize efficient simulation of the sensitivity of the self-powered neutron detector.

The invention discloses a neutron analysis physical testing system and method, and belongs to the technical field of nuclear physical testing. The system comprises a high-speed synchronous pulse generator used for generating pulse signals of various modulation sequences; the ultrashort pulse neutron generator is used for emitting short pulse neutron rays with specified parameters to the sample; the neutron detector is used for acquiring a secondary neutron signal; the gamma detector is used for acquiring a characteristic gamma signal generated by the neutron excitation detection sample; the safety control module is used for controlling the working state of the ultrashort pulse neutron generator; and the data processing device is used for collecting and gathering neutron signals and characteristic gamma signals in real time according to the time sequence of the pulse signals of the multiple modulation sequences. According to the system, time window drift and measurement errors are reduced, the ultra-short pulse neutron generator is started only under the condition that access control signals allow, and the accuracy, safety and stability of stratum physical parameter measurement are improved.

The invention relates to the technical field of data transmission control, in particular to a neutron detection data real-time preprocessing method and system based on edge calculation. The method comprises the following steps: acquiring an original energy spectrum data packet through a high-speed acquisition circuit of an underground instrument and temporarily storing the original energy spectrum data packet into a primary annular buffer area; calculating the geological disturbance index of the current frame data according to the counting difference of the current frame and the previous frame in the feature energy window and the full spectrum information entropy of the current frame; reading the occupancy rate of a communication sending buffer queue in real time, and calculating the dynamic transmission admission probability of the current frame data in combination with the geological disturbance index; and dynamically selecting a compression strategy and a transmission priority of the current frame data according to a comparison result of the dynamic transmission admission probability and a preset threshold value. The problem that key geological information is lost due to the fact that channel bandwidth is limited in deep well logging is solved, preferential fidelity transmission of high-value data is achieved through a coupling mechanism of geology and a channel, and the risk of cache overflow is eliminated.

The laboratory non-contact type loaded coal rock neutron monitoring test device comprises a box body with an opening in the front end and a partition plate which is arranged at the rear end of the inner wall of the box body in a matched mode and divides the box body into a device cavity and an operation cavity, and an experiment table base is arranged at the bottom of the inner wall of the operation cavity. Press machines are arranged on the left side and the right side of the upper end of the experiment table base in a matched mode, a neutron detector is arranged at the position, behind the press machines, of the upper end of the experiment table base, a pre-amplifier is installed on one side in the device cavity, and a high-voltage power module, a time synchronizer and a neutron monitoring controller are arranged on the other side in the device cavity. A data analysis panel is arranged at the open end of the device cavity in a matched mode and controls time synchronization through a time synchronizer, and a plurality of heat dissipation holes distributed in an array mode are backwards formed in the rear end of the inner wall of the device cavity. The neutron radiation test can be carried out, and meanwhile, the neutron discrete coefficient of the coal-rock mass is provided as a neutron radiation anomaly index, so that the coal mine dynamic disaster is predicted.

The invention discloses a preparation method for growing large-size isotope hexagonal boron nitride at normal pressure and high temperature and application of the large-size isotope hexagonal boron nitride in neutron detection, and the method comprises the following steps: uniformly mixing nickel powder, chromium powder and boron powder to obtain a mixture of boron and nickel-chromium alloy; then carrying out deoxidation treatment under the protection gas flow; reducing the pressure of the system, introducing mixed gas of protective gas and reactive protective gas to normal pressure, and protecting; finally, the deoxidized mixture is subjected to secondary stepped heating, heat preservation is carried out after primary heating, and the temperature of primary heating is higher than that of secondary heating; and naturally cooling to room temperature to generate the hexagonal boron nitride crystal. According to the method, the nickel-chromium alloy is adopted as the metal fluxing agent, the large-size and high-quality isotope hexagonal boron nitride single crystal is successfully prepared under the normal pressure condition through the optimized gas atmosphere and stepped temperature control, and the method has important application value in the fields of neutron detection, two-dimensional materials and the like.

A neutron detector comprising an optical fission chamber with a reflective optical cavity and a detection head coupled to the chamber comprising an optical lens and an optical fiber coupler. The invention relates to a neutron detector (1) comprising at least one sealed ionization chamber (2) with optical transduction, called an optical fission chamber (OFC) with a single optical cavity, the operation of which is based on optical transduction and which integrates, at one of its longitudinal ends, a window and an optical lens as an optical interface and, at the other end, a mirror to reflect photons traveling in the opposite direction to that of the window. Figure for the abstract: Fig. 9

The invention relates to the field of nuclear power instrument control, in particular to a reactor core protection system and method, and the system comprises neutron detection equipment which is used for measuring the neutron flux of a reactor core; the upper computer is used for reconstructing reactor core flux power according to the neutron flux so as to generate calibration parameters and sending the calibration parameters to the verification equipment; the verification equipment is used for judging whether the calibration parameters are valid or not according to the neutron flux and the calibration parameters, and sending the calibration parameters to the lower computer when the calibration parameters are valid; the lower computer is used for calculating the minimum deviation nucleation boiling ratio and the local highest linear power density of the reactor core according to the neutron flux and the calibration parameters; and the control equipment is used for controlling a control rod of the reactor core according to the minimum deviation nucleation boiling ratio and the local highest linear power density. According to the invention, the reliability of calibration parameters is effectively improved, and the risk of protection function maloperation is reduced.