Device and method for measuring time series of neutron spectrum of single ball for water pumping and injection

Abstract

The present invention relates to the field of neutron spectrum measurement, and specifically to a device and method for measuring the timing of a single-ball neutron spectrum by pumping and injecting water. The device comprises a double-layer nested shell, a central detector, a water pump, a water injector, a sprayer and a timing analysis system. The central detector is placed at the center of the inner shell, and a single-layer moderation cavity for accommodating a moderator liquid is formed between the double-layer shells. The sprayer works in coordination with the water pump and the water injector to continuously adjust the water flow state and the fog water settling effect in the moderation cavity to form a moderator layer of variable thickness to meet the measurement requirements of neutrons of different energies. The timing control subsystem controls the pumping and injecting operations to be carried out synchronously with the neutron measurement, effectively reducing the loss of neutron information. The central detector is used to detect the prompt gamma-ray signals generated by the reaction of thermal neutrons and neutrons with moderator nuclides, so as to realize the measurement of the neutron spectrum and significantly improve the detection efficiency of the system. The overall device is compact and lightweight in design, easy to transport and deploy on site, and is conducive to popularization and application.

Description

Technical Field

[0001] The invention relates to the field of neutron spectrum measurement, and in particular to a device and method for measuring the neutron spectrum of a single ball subjected to water pumping. Background Art

[0002] Neutron spectrum measurement is of great significance in the fields of neutron radiation protection, nuclear safety, reactor design, etc. It is the basic information for conducting neutron spectrum characteristic research and designing neutron radiation protection materials and devices. Multi-sphere neutron spectrometer has been widely used due to its advantages such as wide measurement energy range, isotropy and simple equipment.

[0003] In order to achieve the purpose of portable multi-ball neutron spectrum measurement, researchers have developed a variety of neutron spectrometers based on liquid moderators, such as: the literature of water pumping and injection multi-layer concentric sphere device and neutron spectrum detection system and a water injection and drainage fully automatic multi-ball neutron spectrometer and measurement method, both of which mention multiple shells that are sequentially set from the inside to the outside, the innermost shell of the shell is set on the surface of the neutron detector, and a gap for accommodating liquid is formed between any two adjacent shells. The purpose of different moderation thicknesses is achieved by filling the gap with liquid moderator. Since water needs to be pumped and injected intermittently into the gap between the multi-layer shells during the measurement process, the entire measurement process takes a long time and cannot achieve rapid measurement of neutron spectrum; the pumping and injection operation links are separated from the actual neutron measurement, resulting in neutron information loss and inaccurate measurement in non-uniform fields. The literature of small liquid-moderated neutron spectrum detection device and detection method mentions that through the structure of the pumping and injecting device, by changing the moderator thickness of the small volume moderation cavity, different thicknesses of moderators can be combined in one container, but the cylindrical structure of the device is dependent on the direction of the incident neutron. The literature Small Sleeve Neutron Spectrum Detection Device and Detection Method mentions using the liquid it carries as a moderator, and changing the pressure of the inner and outer cavities through a liquid level adjustment system to change the thickness of the moderator liquid. However, the limited liquid moderator it carries limits the device's efficiency in moderating neutrons, and there is also a problem of direction dependence.

[0004] Neutron spectrometers based on prompt gamma neutron activation analysis technology can also realize neutron spectrum measurement. For example, the literature describes a neutron spectrum measurement device and a measurement method thereof and a wide-energy neutron dose equivalent rate meter based on a gamma-ray spectrum detector. Both of them mention that prompt gamma rays generated by the reaction of neutrons with various nuclides in the device are detected by gamma detectors, and the energy and intensity of characteristic gamma rays are used to analyze the neutron spectrum. However, in order to obtain prompt gamma rays of multiple nuclides, multiple materials need to be stacked layer by layer, which is heavy and inconvenient to transport. Summary of the invention

[0005] One of the purposes of the present invention is to provide a water-pumped single-ball neutron energy spectrum timing measurement device, which uses water as a moderator and combines a variety of moderator combinations of different thicknesses in a single container to solve the problem of multiple materials being stacked layer by layer and having a large mass, and the overall device is compact and light.

[0006] The single-ball neutron spectrum timing measurement device for water extraction and injection in this scheme includes a double-layer nested shell, a central detector, a water extractor, a water injector, an exhauster, a sprayer and a timing analysis system;

[0007] The double-layer nested shell includes an inner shell and an outer shell fixed together, the inner shell is tightly sleeved on the surface of the central detector, and the outer shell surrounds the inner shell to form a single-layer moderation cavity for containing moderator liquid, and the moderator liquid includes two states of water flow and spray;

[0008] The outer shell is provided with a top valve at the top and a bottom valve at the bottom; the water pump is connected to the bottom valve and is used to extract liquid from the moderator cavity to adjust the moderator liquid content in the moderator cavity; the water injector is connected to the top valve and is used to inject liquid into the moderator cavity to increase the liquid flow in the moderator cavity;

[0009] A sprayer connected to the top valve is provided on the inner side of the top of the outer shell, and is used to convert the moderator liquid injected from the water injector through the top valve into a uniform and fine water mist form;

[0010] An exhaust device is provided on the top of the outer shell, and an exhaust pipe is inserted into the exhaust device;

[0011] The central detector is used to detect thermal neutrons moderated by the moderator and prompt characteristic gamma rays released by nuclear reactions between neutrons and nuclides in the moderator, and form electrical pulse signals;

[0012] The timing analysis system is used to control the time of extraction and injection of moderator fluid, the extraction and injection rate, the valve opening and closing time, and the activation of the sprayer, receive and process the neutron and prompt gamma-ray signals of the central detector, and adjust the working status of the water pump, water injector and sprayer according to the feedback real-time data. After completing all data measurements, the timing analysis system outputs the energy spectrum information of the measured neutron field after processing and calculation.

[0013] Furthermore, the water pump is a pipe with one end connected to the moderation chamber through a bottom valve and open at one end, and the water injector is a pipe with one end connected to the sprayer through a top valve and open at one end.

[0014] Furthermore, the outer shell and the inner shell are made of polyethylene, stainless steel, aluminum, or a mixture of polyethylene, stainless steel, and aluminum; and the thickness of the outer shell and the inner shell is 1 to 5 mm.

[0015] Furthermore, the sprayer includes a plurality of nozzles, which are evenly distributed on the top of the moderation cavity to ensure that the water mist can be evenly distributed in the moderation cavity.

[0016] Further, the timing analysis system includes a timing control subsystem and a data acquisition and processing subsystem;

[0017] The timing control subsystem includes a sensor, a controller and an actuator assembly. The sensor is used to monitor and feedback the water level, flow rate and spray state parameters inside the moderator chamber in real time. The controller intelligently controls the pumping, water injection, exhaust and sprayer opening and closing actions and durations to maintain continuous neutron measurement according to a preset timing program. The actuator assembly is used to respond to instructions issued by the controller to perform fine adjustments to water injection, extraction rate and spray size, so that the dynamic changes of the moderator are synchronized with the neutron measurement.

[0018] The data acquisition and processing subsystem is electrically connected to the central detector, and is used to receive and process the neutron and prompt gamma-ray signals of the central detector, and to feed back the processed signal data to the timing control subsystem in real time. The timing control subsystem adjusts the working status of the water pump, water injector and sprayer according to the real-time data fed back. After completing all data measurements, the data acquisition and processing subsystem outputs the energy spectrum information of the measured neutron field after processing and calculation.

[0019] Furthermore, the center detector is Cs2 6 LiYCl6 scintillator detector or NaI(Tl+Li) scintillator detector or other detectors with n and γ dual detection performance.

[0020] The second object of the present invention is to provide a method for measuring the neutron energy spectrum of a single ball during water pumping and injection, so that the water pumping and injection operation can be carried out synchronously with the neutron measurement to reduce the interference of the neutron field.

[0021] The method for measuring the time series of neutron spectrum of a single ball during water pumping and injection comprises the following steps:

[0022] Step 1, using the Monte Carlo method to simulate the n-γ response function matrix of the single-ball neutron spectrum timing measurement device for water pumping and water injection in the water injection state and the water pumping state;

[0023] Step 2: Place the single-ball neutron spectrum timing measurement device for water pumping in the detection area, keep the moderator chamber free of moderator liquid, allow neutrons to be incident on the central detector from a specific direction, and import the n-γ response function matrix in step 1;

[0024] Step 3, starting the timing analysis system to generate a series of first time series for controlling the operation of the water injector and the sprayer, each first time series including time information of each stage of the water injection cycle;

[0025] Step 4: At the first time sequence, the water injector and the sprayer are started synchronously to continuously inject the moderator liquid into the moderator cavity, and the central detector captures and records the neutron and prompt gamma ray pulse signals in real time. The pulse signals are converted into digital signals through the data acquisition and processing subsystem, and are transmitted to the timing control subsystem in real time strictly according to the first time sequence;

[0026] Step 5: The central detector records the neutron and prompt gamma pulse signals with changing intensities during the injection of the moderator liquid. The data acquisition and processing subsystem automatically records the water injection rate in each first time series, the sedimentation effect caused by spraying in the moderator cavity, and the associated neutron and prompt gamma ray signals, so that the timing control subsystem can flexibly adjust the water injection rate of the water injection device and the spray volume and uniformity of the sprayer according to the data obtained in real time.

[0027] Step 6, repeating Step 4 and Step 5 until the total duration of the first time sequence is reached or the moderator chamber reaches a predetermined moderator liquid filling content, at which time the timing control subsystem is paused;

[0028] Step 7: Start a new second time sequence for controlling the action of the water pump. Start the water pump at the initial moment of the second time sequence to start continuously extracting the moderator liquid in the moderation chamber. At the same time, the central detector continues to monitor and record the neutron and prompt gamma pulse signals. The data acquisition and processing subsystem converts these signals into digital signals and transmits them to the timing control subsystem according to the second time sequence. The timing control system dynamically adjusts the pumping rate of the water pump according to the real-time feedback data to ensure the smooth extraction and stable measurement of the moderator liquid in the moderation chamber.

[0029] Step 8: During the whole process of pumping, the data acquisition and processing subsystem continuously records the pumping rate at each time node of the second time series and the corresponding neutron and prompt gamma ray signals;

[0030] Step 9, repeating Step 7 and Step 8 until the total duration of the second time sequence is reached or the moderator fluid in the moderation chamber is reduced to a preset threshold, and then shutting down the timing control subsystem;

[0031] Step ten, adjust the time interval settings of the first time series and the second time series, repeat steps one to nine, complete a set number of complete measurement cycles, analyze the neutron and prompt gamma pulse signals during the injection and pumping processes of the set number of times through the data acquisition and processing subsystem, and after processing and calculation, take the average value of the set number of times to form a matrix, and solve it with the response function matrix of step one, so as to output the energy spectrum information of the measured neutron field.

[0032] Further, in step 1, the calculation process of the response function matrix is:

[0033] Step 1-1, calculating the moderator liquid content and spray state corresponding to the moderator cavity in the water injection and pumping process according to a preset time series, and setting the volume corresponding to the moderator liquid content and the density of the material corresponding to the spray state in the Monte Carlo program;

[0034] Step 1-2, in the water injection stage, S1 types of slowing-down thickness structures are formed in the slowing-down chamber, and the corresponding neutron and gamma-ray responses of each case are different; -9 In the energy range of ~20MeV, the neutron energy interval is divided into n energy groups;

[0035] The water injection neutron response matrix of S1 row and n column is obtained by Monte Carlo simulation. and the water injection gamma ray response matrix Respectively expressed as:

[0036]

[0037]

[0038] Step 1-3, in the pumping stage, S2 types of slowing-down thickness structures are formed in the slowing-down cavity 9, and the corresponding neutron and gamma-ray responses in each case are different; -9 In the energy range of ~20MeV, the neutron energy interval is divided into n energy groups;

[0039] The pumping neutron response matrix of S2 rows and n columns is obtained by Monte Carlo simulation. and the pumping gamma ray response matrix Respectively expressed as:

[0040]

[0041]

[0042] Steps 1-4 finally form the n-γ response function matrix R of the single ball for water pumping and injection, which is expressed as:

[0043]

[0044] Further, the specific process of step 4 is:

[0045] Step 4-1, close the bottom valve, open the top valve and the sprayer, continuously inject the moderator liquid into the water injection pipe, convert it into uniform and fine water mist through the sprayer, and spray it evenly inside the moderator cavity through the nozzle to form a uniformly distributed mist water settling effect;

[0046] Step 4-2, according to the set first time sequence, at the first time point of the first time sequence, the central detector outputs the first measured neutron and prompt gamma ray pulse signal, and the data acquisition and processing subsystem converts the pulse signal into a digital signal, and calculates the digital signal count value N1 of the initial measurement;

[0047] Step 4-3, according to the preset time interval of the first time series, when the 2nd to S1th time points are reached in sequence, the central detector continuously records the pulse signal at each time point, and the data acquisition and processing subsystem converts the pulse signal into digital signals one by one, and calculates the digital signal count value N1-NS1 corresponding to each time point in sequence.

[0048] Further, the specific process of step seven is:

[0049] Step 7-1, close the top valve and the spray device, open the bottom valve, and continuously pump out the moderator liquid in the moderator chamber from the pumping pipe;

[0050] Step 7-2, according to the set second time sequence, at the first time point of the second time sequence, the central detector outputs the pulse signal of the first measurement, and the data acquisition and processing subsystem converts the pulse signal into a digital signal, and calculates the digital signal count value M1 of the initial measurement;

[0051] Step 7-3, according to the preset time interval of the second time series, when the 2nd to S2th time points are reached in sequence, the central detector continuously records the pulse signal at each time point, and the data acquisition and processing subsystem converts the pulse signal into digital signals one by one, and calculates the digital signal count values ​​M1-MS2 corresponding to each time point in sequence.

[0052] Compared with the prior art, the beneficial effects of this solution are:

[0053] (1) The neutron spectrometer method in the prior art that requires the use of multiple "physical moderator spheres" is changed. By adjusting the liquid state in the single-sphere moderator cavity (fog water settling effect and water flow change), a variety of moderation combinations are formed. The overall structure of the device is simple, the equipment components are few, and the weight is light.

[0054] (2) The timing control system is used to achieve the synchronization of water pumping and injection operations and neutron measurement, which significantly improves the measurement efficiency. Synchronous measurement reduces the loss of neutron information caused by operation delays, ensures the continuity and integrity of the measurement, and has little disturbance to the neutron field to be measured. It can be used in scenarios that require rapid measurement.

[0055] (3) The incident neutron information can be obtained by simply using the difference in neutron response under different moderation conditions, or by using the prompt characteristic gamma rays released by the nuclear reaction between thermal neutrons and moderator liquid nuclides, or by combining the above two methods, thus realizing the measurement of neutron energy spectrum using one device and multiple methods.

[0056] (4) The device adopts a spherical structure and has a consistent response to neutrons incident from different directions, which can avoid measurement deviations caused by directionality and improve the accuracy of measurement results.

[0057] (5) The device adopts a single moderator sphere structure, which is compact and lightweight, easy to carry and deploy on site. It can be used for neutron spectrum measurement in narrow spaces or special locations.

[0058] (6) The device is easy to obtain materials and simple to process, which greatly reduces the difficulty and cost of equipment manufacturing and maintenance, and is conducive to the promotion and use of technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 It is a front view of the water injection structure of the single-ball neutron spectrum timing measurement device for water extraction and injection in the first embodiment of the present invention;

[0060] Figure 2 It is a front view of the water pumping structure of the water pumping and injection single-ball neutron spectrum timing measurement device in the first embodiment of the present invention;

[0061] Figure 3 This is a matrix diagram of the n-γ response function of the single-sphere neutron spectrum time-series measurement of water pumping and injection in Example 3 of the present invention. DETAILED DESCRIPTION

[0062] The following is further explained in detail through specific implementation methods.

[0063] The reference numerals in the drawings of the specification include: central detector 1, double-layer nested shell 2, water injector 3, water pump 4, exhauster 5, water flow state moderator 6, spray state moderator 7, sprayer 8, moderator cavity 9.

[0064] Embodiment 1

[0065] Single ball neutron spectrum timing measurement device for water pumping and injection, such as Figure 1 and Figure 2 As shown: it includes a double-layer nested shell 2, a central detector 1, a water pump 4, a water injector 3, an exhauster 5, a sprayer 8 and a timing analysis system;

[0066] The double-layer nested shell 2 includes an inner shell and an outer shell fixed together. The inner shell is tightly sleeved on the surface of the central detector 1. The gap between the inner shell and the central detector 1 is less than 1 mm. The outer shell forms a single-layer moderator cavity 9 around the inner shell. The moderator cavity 9 is used to accommodate a moderator liquid. The moderator liquid includes a water flow state moderator liquid 6 and a spray state moderator liquid 7. The moderator liquid is a liquid with good moderation performance, such as water, heavy water, boron-containing solution, lithium-containing solution or liquid grease. Preferably, the moderator liquid is water, which is economical and easy to use.

[0067] The material of the outer shell and the inner shell is polyethylene, stainless steel, aluminum, or a mixture of polyethylene, stainless steel, and aluminum; taking the double-layer nested shell 2 made of aluminum as an example, the aluminum material can be single aluminum or aluminum alloy, and this embodiment does not limit this. The density of aluminum is small, and the double-layer nested shell 2 with a smaller thickness made of aluminum material is greatly reduced in weight compared with stainless steel material. The thickness of the outer shell and the inner shell is 1 to 5 mm. In this embodiment, the optimal thickness is set to 2 mm under the premise of ensuring measurement performance and structural stability.

[0068] The top of the outer shell is provided with a top valve, and the bottom is provided with a bottom valve, and both the top valve and the bottom valve are existing products according to actual needs. The water pump 4 is connected to the bottom valve, and the water pump 4 is used to extract liquid from the moderation cavity 9 to adjust the moderation liquid content in the moderation cavity 9; the water injector 3 is connected to the top valve, and the water injector 3 is used to inject liquid into the moderation cavity 9 to increase the liquid flow in the moderation cavity 9. The water pump 4 is a pipe with one end connected to the moderation cavity 9 through the bottom valve and one end open, and the water injector 3 is a pipe with one end connected to the sprayer 8 through the top valve.

[0069] A sprayer 8 connected to the top valve is installed on the inner side of the top of the outer shell. The sprayer 8 is used to convert the moderator liquid injected from the water injector 3 through the top valve into a uniform and fine water mist. The sprayer 8 can use an existing spray structure, which will not be described here. The sprayer 8 includes a plurality of nozzles, the number of which is set according to actual needs, and the nozzles are evenly distributed on the top of the moderation cavity 9 to ensure that the water mist can be evenly distributed in the moderation cavity 9.

[0070] An exhauster 5 is installed on the top of the outer shell, and an exhaust pipe is inserted into the exhauster 5.

[0071] The central detector 1 is used to detect thermal neutrons moderated by the moderator and the prompt characteristic gamma rays released by the nuclear reaction between neutrons and nuclides in the moderator, and form electrical pulse signals. 6 2LiYCl6 scintillator detector or NaI(Tl+Li) scintillator detector or other detectors with n and γ dual detection performance.

[0072] The timing analysis system is used to control the time of moderator liquid extraction and injection, the extraction rate, the valve opening and closing time, and the activation of the sprayer 8, and obtain the count value output by the signal acquisition unit each time to form a count value matrix, and solve it with the pre-stored response function matrix to obtain the neutron energy spectrum.

[0073] The timing analysis system includes a timing control subsystem and a data acquisition and processing subsystem. The timing control subsystem includes sensors, controllers, and actuator components. The sensors are used to monitor and feedback the water level, flow rate, and spray state parameters inside the moderator chamber in real time. The sensors can use existing sensor products. The controller intelligently controls the pumping, water injection, exhaust, and opening and closing actions and duration of the sprayer 8 to maintain continuous neutron measurement according to the preset timing program. The controller can use the existing STM single-chip microcomputer chip. The actuator component is used to respond to the instructions issued by the controller to perform fine adjustments to the water injection and extraction rates and spray size, so that the dynamic changes of the moderator are synchronized with the neutron measurement, ensuring that the dynamic changes of the moderator can be synchronized with the neutron measurement.

[0074] The data acquisition and processing subsystem is electrically connected to the central detector 1, and is used to receive and process the neutron and prompt gamma-ray signals of the central detector 1, and to feed back the processed signal data to the timing control subsystem in real time. The timing control subsystem adjusts the working states of the water pump 4, the water injector 3 and the sprayer 8 according to the real-time data fed back. After completing all data measurements, the data acquisition and processing subsystem outputs the energy spectrum information of the measured neutron field after processing and calculation.

[0075] The device of the first embodiment has the following advantages compared with the existing device:

[0076] (1) The timing control system is adopted to achieve the synchronization of water pumping and injection operations and neutron measurement, which significantly improves the measurement efficiency. Synchronous measurement reduces the loss of neutron information caused by operation delay, ensures the continuity and integrity of the measurement, and has little disturbance to the neutron field to be measured. It can be used in scenarios that require rapid measurement.

[0077] (2) The device for measuring the neutron energy spectrum of a single ball by pumping water can analyze the incident neutron information only through the response difference of neutrons under different moderation conditions; it can also use the nuclear reaction between thermal neutrons and the moderator liquid in the moderation cavity 9 to obtain prompt characteristic gamma rays, and further analyze the intensity and energy of the characteristic gamma rays to obtain the information of the incident neutrons, such as the number and energy distribution of the incident neutrons; further, the above two methods can be combined to obtain the incident neutron information, and the three methods of measuring the neutron energy spectrum can be realized through a set of devices.

[0078] (3) The device adopts a spherical structure and has a consistent response to neutrons incident from different directions, which can avoid measurement deviations caused by directionality and improve the accuracy of measurement results.

[0079] Embodiment 2

[0080] Based on the device of embodiment 1, a method for measuring the neutron spectrum of a single ball with water pumping and injection is provided, such as Figure 3 As shown, the following steps are included:

[0081] Step 1: Monte Carlo method is used to simulate the n-γ response function matrix of the single-ball neutron spectrum timing measurement device for water pumping and water injection in the water injection state and the water pumping state. The specific simulation process is as follows:

[0082] Step 1-1, calculating the moderator liquid content and spray state corresponding to the moderator cavity 9 in the water injection and pumping process according to a preset time series, and setting the volume corresponding to the moderator liquid content and the density of the material corresponding to the spray state in the Monte Carlo program;

[0083] Step 1-2, in the water injection stage, S1 types of slowing-down thickness structures are formed in the slowing-down cavity 9, and the corresponding neutron and gamma-ray responses of each case are different; -9 In the energy range of ~20MeV, the neutron energy interval is divided into n energy groups;

[0084] The water injection neutron response matrix of S1 row and n column is obtained by Monte Carlo simulation. and the water injection gamma ray response matrix Respectively expressed as:

[0085]

[0086]

[0087] Step 1-3, in the pumping stage, S2 types of slowing-down thickness structures are formed in the slowing-down cavity 9, and the corresponding neutron and gamma-ray responses in each case are different; -9 In the energy range of ~20MeV, the neutron energy interval is divided into n energy groups;

[0088] The pumping neutron response matrix of S2 rows and n columns is obtained by Monte Carlo simulation. and the pumping gamma ray response matrix Respectively expressed as:

[0089]

[0090]

[0091] Steps 1-4 finally form the n-γ response function matrix R of the single ball for water pumping and injection, which is expressed as:

[0092]

[0093] Step 2: Place the single-ball neutron spectrum timing measurement device for water pumping in the detection area, keep the moderator chamber 9 free of moderator liquid, allow neutrons to be incident on the central detector 1 from a specific direction, and import the n-γ response function matrix in step 1;

[0094] Step 3, generating a series of first time series for controlling the operation of the water injector 3 and the sprayer 8, each first time series including time information of each stage of the water injection cycle;

[0095] Step 4: At the first time sequence, the water injector 3 and the sprayer 8 are started synchronously, so that the moderator fluid begins to be continuously injected into the moderator cavity 9, and the central detector 1 captures and records the neutron and prompt gamma ray pulse signals in real time, and the pulse signals are converted into digital signals through the data acquisition and processing subsystem, and transmitted to the timing control subsystem in real time in strict accordance with the first time sequence. Specifically:

[0096] Step 4-1, close the bottom valve, open the top valve and the sprayer 8, continuously inject the moderator liquid into the water injection pipe, finely atomize it through the sprayer 8, convert it into uniform and fine water mist, and spray it evenly inside the moderator cavity 9 through the nozzle to form a uniformly distributed mist water settling effect;

[0097] Fine atomization is as follows: close the bottom valve, open the top valve and the sprayer 8, continuously inject the moderator liquid into the water injection pipe, and the sprayer 8 atomizes the moderator liquid into a uniform and fine water mist with a particle size between 50 and 100 um. The atomized moderator liquid is evenly distributed in the moderation cavity 9 through the nozzle, producing a uniformly distributed mist water settling effect.

[0098] Step 4-2, according to the set first time sequence, at the first time point of the first time sequence, the central detector 1 outputs the first measured neutron and prompt gamma ray pulse signal, and the data acquisition and processing subsystem converts the pulse signal into a digital signal and calculates the digital signal count value N1 of the initial measurement.

[0099] Step 4-3, according to the preset time interval of the first time series, when the 2nd to S1th time points are reached in sequence, the central detector 1 continuously records the pulse signal at each time point, and the data acquisition and processing subsystem converts the pulse signal into a digital signal one by one, and calculates the digital signal count value N1-NS1 corresponding to each time point in sequence.

[0100] Step five, the central detector 1 records the neutron and prompt gamma pulse signals whose intensities change during the injection of the moderator liquid, and the data acquisition and processing subsystem automatically records the water injection rate in each first time series, the sedimentation effect caused by spraying in the moderation cavity 9, and the associated neutron and prompt gamma ray signals, so that the timing control subsystem can flexibly adjust the water injection rate of the water injection device and the spray volume and uniformity of the sprayer 8 according to the data obtained in real time.

[0101] During flexible adjustment, if the central detector 1 detects that the pulse signal intensity of neutrons and gamma rays suddenly increases, indicating that the moderation capacity is too strong, the timing control subsystem will instruct the water injector 3 to reduce the water injection rate, and at the same time reduce the spray volume and spray frequency of the sprayer 8 to weaken the moderation effect; if it is found that the neutron flux in a certain area in the moderation cavity 9 is too high, the timing control subsystem will instruct the sprayer 8 to adjust the spray pattern, including changing the direction of the nozzle or increasing the distribution density of the spray points, so as to achieve a more uniform moderation effect.

[0102] Step 6, repeating steps 4 and 5 until the total duration of the first time sequence is reached or the moderator chamber 9 reaches a predetermined moderator liquid filling content, at which time the timing control subsystem is paused;

[0103] Step 7: Start a new second time sequence for controlling the action of the water pump 4. Start the water pump 4 at the initial moment of the second time sequence to start continuously extracting the moderator liquid in the moderation cavity 9. At the same time, the central detector 1 continues to monitor and record the neutron and prompt gamma pulse signals, and the data acquisition and processing subsystem converts these signals into digital signals, and transmits them to the timing control subsystem according to the second time sequence. The timing control system dynamically adjusts the pumping rate of the water pump 4 according to the real-time feedback data, so that the moderator liquid in the moderation cavity 9 can be smoothly extracted and stably measured; specifically including:

[0104] Step 7-1, close the top valve and the spray device, open the bottom valve, and continuously pump out the moderator liquid in the moderation chamber 9 from the pumping pipe.

[0105] Step 7-2, according to the set second time series, at the first time point of the second time series, the central detector 1 outputs the first measured pulse signal, allowing the data acquisition and processing subsystem to convert the pulse signal into a digital signal and calculate the digital signal count value M1 of the initial measurement.

[0106] Step 7-3, according to the preset time interval of the second time series, when the 2nd to S2th time points are reached in sequence, the central detector 1 continuously records the pulse signal at each time point, and the data acquisition and processing subsystem converts the pulse signal into a digital signal one by one, and calculates the digital signal count value M1-MS2 corresponding to each time point in sequence.

[0107] Step 8: During the whole process of pumping, the data acquisition and processing subsystem continuously records the pumping rate at each time node of the second time series and the corresponding neutron and prompt gamma ray signals;

[0108] Step 9, repeating steps 7 and 8 until the total duration of the second time sequence is reached or the moderator liquid in the moderation chamber 9 is reduced to a preset threshold, and then shutting down the timing control subsystem;

[0109] Step 10, adjust the time interval setting of the first time series and the second time series, repeat steps 1 to 9, complete the set number of complete measurement cycles, analyze the neutron and prompt gamma pulse signals during the set number of water injection and pumping processes through the data acquisition and processing subsystem, and after processing and calculation, take the average value of the set number of times to form a matrix, and solve it with the response function matrix of step 1, so as to output the energy spectrum information of the measured neutron field. The solution process of the energy spectrum information is:

[0110] Step 10-1, the data processing system forms a counting matrix with one row and 2×(S1+S2) columns by respectively converting the S1+S2 thermal neutron and prompt gamma ray count values, which is expressed as:

[0111]

[0112] Step 6-2, calculate according to the calculation formula of neutron energy spectrum:

[0113]

[0114] Among them, C k is the detector count, R k is the response function of the detector at energy E, Φ(E) is the incident neutron energy spectrum flux with energy E;

[0115] Step 10-3, discretize the formula of step 10-2 to obtain:

[0116]

[0117] Substitute the count matrix from step 10-1 and the response function matrix from step 1-4 into step 10-3 to obtain:

[0118]

[0119] in, This is the neutron energy spectrum of the area to be tested.

[0120] In the second embodiment, the central detector 1 is used to detect the prompt gamma ray signals generated by the reaction of thermal neutrons and neutrons with moderator nuclides through the measurement method, so as to measure the neutron energy spectrum and significantly improve the detection efficiency of the system. The pumping and injection operation participates in the neutron energy spectrum measurement in real time, which helps to reduce the interference of the neutron field. The overall device is compact and lightweight, easy to transport and deploy on site, and is conducive to promotion and application.

[0121] Embodiment 3

[0122] On the basis of Example 1 and Example 2, a certain device and a certain measurement method are used for verification and explanation. In the single-ball neutron spectrum timing measurement device for water pumping, the outer spherical shell radius of the double-layer nested shell 2 is 22.8 cm, the wall thickness is 2 mm, the inner layer is a cylindrical aluminum shell with a height of 9 cm, a radius of 3 cm, and a thickness of 2 mm, and the central detector 1 is a cylindrical CLYC scintillator detector with a radius of 2.54 cm and a height of 10.16 cm. The rest is the same as Example 1.

[0123] The Monte Carlo simulation program was used to simulate the water injection response function matrix R corresponding to the moderator fluid 7 with five different spray states, as shown in Figure 3 In the data acquisition and processing subsystem, the neutron energy spectrum to be measured is calculated by combining the 5 count values ​​of neutrons and prompt gamma and the water injection response function matrix R, and after the measurement is completed, the moderator liquid 7 is discharged to the outside through the pipeline connected to the water pump 4.

[0124] The above is only an embodiment of the present invention, and the common knowledge such as the known specific structure and characteristics in the scheme is not described in detail here. It should be pointed out that for those skilled in the art, several deformations and improvements can be made without departing from the structure of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A single-ball neutron spectrum timing measurement device for pumping and injecting water, including a double-layer nested shell, a central detector, a pump, a water injector, an exhauster, a sprayer and a timing analysis system; Features: The double-layer nested shell includes an inner shell and an outer shell fixed together, the inner shell is tightly sleeved on the surface of the central detector, and the outer shell surrounds the inner shell to form a single-layer moderation cavity for containing moderator liquid, and the moderator liquid includes two states of water flow and spray; The outer shell is provided with a top valve at the top and a bottom valve at the bottom; the water pump is connected to the bottom valve and is used to extract liquid from the moderator cavity to adjust the moderator liquid content in the moderator cavity; the water injector is connected to the top valve and is used to inject liquid into the moderator cavity to increase the liquid flow in the moderator cavity; A sprayer connected to the top valve is provided on the inner side of the top of the outer shell, and is used to convert the moderator liquid injected from the water injector through the top valve into a uniform and fine water mist form; An exhaust device is provided on the top of the outer shell, and an exhaust pipe is inserted into the exhaust device; The central detector is used to detect thermal neutrons moderated by the moderator and prompt characteristic gamma rays released by nuclear reactions between neutrons and nuclides in the moderator, and form electrical pulse signals; The timing analysis system is used to control the time of extraction and injection of moderator fluid, the extraction and injection rate, the valve opening and closing time, and the activation of the sprayer, receive and process the neutron and prompt gamma-ray signals of the central detector, and adjust the working status of the water pump, water injector and sprayer according to the feedback real-time data. After completing all data measurements, the timing analysis system outputs the energy spectrum information of the measured neutron field after processing and calculation.

2. The device for measuring the neutron spectrum of a single ball during water pumping and injection according to claim 1 is characterized in that: The water pump is a pipe with one end connected to the moderation chamber through a bottom valve and one end open, and the water injector is a pipe with one end connected to the sprayer through a top valve and one end open.

3. The device for measuring the neutron spectrum of a single ball for water pumping and injection according to claim 2 is characterized in that: The outer shell and the inner shell are made of polyethylene, stainless steel, aluminum, or a mixture of polyethylene, stainless steel, and aluminum; the thickness of the outer shell and the inner shell is 1-5 mm.

4. The device for measuring the time series of neutron spectrum of a single ball for pumping water according to claim 3 is characterized in that: The sprayer includes a plurality of nozzles, which are evenly distributed on the top of the moderation cavity to ensure that the water mist can be evenly distributed in the moderation cavity.

5. The device for measuring the time series of neutron spectrum of a single ball for water pumping and injection according to claim 4 is characterized in that: The timing analysis system includes a timing control subsystem and a data acquisition and processing subsystem; The timing control subsystem includes a sensor, a controller and an actuator assembly. The sensor is used to monitor and feedback the water level, flow rate and spray state parameters inside the moderator chamber in real time. The controller intelligently controls the pumping, water injection, exhaust and sprayer opening and closing actions and durations to maintain continuous neutron measurement according to a preset timing program. The actuator assembly is used to respond to instructions issued by the controller to perform fine adjustments to water injection, extraction rate and spray size, so that the dynamic changes of the moderator are synchronized with the neutron measurement. The data acquisition and processing subsystem is electrically connected to the central detector, and is used to receive and process the neutron and prompt gamma-ray signals of the central detector, and to feed back the processed signal data to the timing control subsystem in real time. The timing control subsystem adjusts the working status of the water pump, water injector and sprayer according to the real-time data fed back. After completing all data measurements, the data acquisition and processing subsystem outputs the energy spectrum information of the measured neutron field after processing and calculation.

6. The device for measuring the neutron spectrum of a single ball during water pumping and injection according to claim 5 is characterized in that: The central detector is Scintillator detector or NaI(Tl+Li) scintillator detector or other detectors with n and γ dual detection performance.

7. A method for measuring the time series of neutron spectrum of a single ball of water injection based on the device for measuring the time series of neutron spectrum of a single ball of water injection as claimed in claim 6, characterized in that: The following steps are involved: Step 1, using the Monte Carlo method to simulate the n-γ response function matrix of the single-ball neutron spectrum timing measurement device for water pumping and water injection in the water injection state and the water pumping state; Step 2: Place the single-ball neutron spectrum timing measurement device for water pumping in the detection area, keep the moderator chamber free of moderator liquid, allow neutrons to be incident on the central detector from a specific direction, and import the n-γ response function matrix in step 1; Step 3, starting the timing analysis system to generate a series of first time series for controlling the operation of the water injector and the sprayer, each first time series including time information of each stage of the water injection cycle; Step 4: At the first time sequence, the water injector and the sprayer are started synchronously to continuously inject the moderator liquid into the moderator cavity, and the central detector captures and records the neutron and prompt gamma ray pulse signals in real time. The pulse signals are converted into digital signals through the data acquisition and processing subsystem, and are transmitted to the timing control subsystem in real time strictly according to the first time sequence; Step 5: The central detector records the neutron and prompt gamma pulse signals with changing intensities during the injection of the moderator liquid. The data acquisition and processing subsystem automatically records the water injection rate in each first time series, the sedimentation effect caused by spraying in the moderator cavity, and the associated neutron and prompt gamma ray signals, so that the timing control subsystem can flexibly adjust the water injection rate of the water injection device and the spray volume and uniformity of the sprayer according to the data obtained in real time. Step 6, repeating Step 4 and Step 5 until the total duration of the first time sequence is reached or the moderator chamber reaches a predetermined moderator liquid filling content, at which time the timing control subsystem is paused; Step 7: Start a new second time sequence for controlling the action of the water pump. Start the water pump at the initial moment of the second time sequence to start continuously extracting the moderator liquid in the moderation chamber. At the same time, the central detector continues to monitor and record the neutron and prompt gamma pulse signals. The data acquisition and processing subsystem converts these signals into digital signals and transmits them to the timing control subsystem according to the second time sequence. The timing control system dynamically adjusts the pumping rate of the water pump according to the real-time feedback data to ensure the smooth extraction and stable measurement of the moderator liquid in the moderation chamber. Step 8: During the whole process of pumping, the data acquisition and processing subsystem continuously records the pumping rate at each time node of the second time series and the corresponding neutron and prompt gamma ray signals; Step 9, repeating Step 7 and Step 8 until the total duration of the second time sequence is reached or the moderator fluid in the moderation chamber is reduced to a preset threshold, and then shutting down the timing control subsystem; Step ten, adjust the time interval settings of the first time series and the second time series, repeat steps one to nine, complete a set number of complete measurement cycles, analyze the neutron and prompt gamma pulse signals during the injection and pumping processes of the set number of times through the data acquisition and processing subsystem, and after processing and calculation, take the average value of the set number of times to form a matrix, and solve it with the response function matrix of step one, so as to output the energy spectrum information of the measured neutron field.

8. The method for measuring the time series of neutron spectrum of a single ball during water pumping and injection according to claim 7 is characterized in that: In step 1, the calculation process of the response function matrix is: Step 1-1, calculating the moderator liquid content and spray state corresponding to the moderator cavity in the water injection and pumping process according to a preset time series, and setting the volume corresponding to the moderator liquid content and the density of the material corresponding to the spray state in the Monte Carlo program; Step 1-2, in the water injection stage, S1 types of slowing-down thickness structures are formed in the slowing-down chamber, and the corresponding neutron and gamma-ray responses of each case are different; -9 In the ~20MeV energy range, the neutron energy range is divided into n energy groups; The water injection neutron response matrix of S1 row and n column is obtained by Monte Carlo simulation. and the water injection gamma ray response matrix , respectively expressed as: ； ； Step 1-3, in the pumping stage, S2 types of slowing-down thickness structures are formed in the slowing-down cavity 9, and the corresponding neutron and gamma-ray responses in each case are different; -9 In the ~20MeV energy range, the neutron energy range is divided into n energy groups; The pumping neutron response matrix of S2 rows and n columns is obtained by Monte Carlo simulation. and the pumping gamma ray response matrix , respectively expressed as: ； ； Steps 1-4 finally form the n-γ response function matrix R of the single ball for water pumping and injection, which is expressed as: 。 9. The method for measuring the time series of neutron spectrum of a single ball during water pumping and injection according to claim 7, characterized in that: The specific process of step 4 is as follows: Step 4-1, close the bottom valve, open the top valve and the sprayer, continuously inject the moderator liquid into the water injection pipe, convert it into uniform and fine water mist through the sprayer, and spray it evenly inside the moderator cavity through the nozzle to form a uniformly distributed mist water settling effect; Step 4-2, according to the set first time sequence, at the first time point of the first time sequence, the central detector outputs the first measured neutron and prompt gamma ray pulse signal, and the data acquisition and processing subsystem converts the pulse signal into a digital signal, and calculates the digital signal count value N1 of the initial measurement; Step 4-3, according to the preset time interval of the first time series, when the 2nd to S1th time points are reached in sequence, the central detector continuously records the pulse signal at each time point, and the data acquisition and processing subsystem converts the pulse signal into a digital signal one by one, and calculates the digital signal count value N1-NS1 corresponding to each time point in sequence.

10. The method for measuring the time series of neutron spectrum of a single ball during water pumping and injection according to claim 7, characterized in that: The specific process of step seven is as follows: Step 7-1, close the top valve and the spray device, open the bottom valve, and continuously pump out the moderator liquid in the moderator chamber from the pumping pipe; Step 7-2, according to the set second time sequence, at the first time point of the second time sequence, the central detector outputs the pulse signal of the first measurement, and the data acquisition and processing subsystem converts the pulse signal into a digital signal, and calculates the digital signal count value M1 of the initial measurement; Step 7-3, according to the preset time interval of the second time series, when the 2nd to S2th time points are reached in sequence, the central detector continuously records the pulse signal at each time point, and the data acquisition and processing subsystem converts the pulse signal into digital signals one by one, and calculates the digital signal count values ​​M1-MS2 corresponding to each time point in sequence.

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