Liquid scintillation measurement method for beam intensity with a large dynamic range using beam current

Abstract

The present invention discloses a liquid scintillator measurement method for beam intensity with a large dynamic range using a beam current. The method comprises the following steps: S1: preparing a liquid scintillator in a liquid scintillator circulation monitoring device; S2: circulating the liquid scintillator through the liquid scintillator circulation monitoring device while measuring the beam current intensity and replenishing fresh liquid scintillator; S3: reading the measurement results of the liquid scintillator performance measurement system through a PLC controller, adjusting the fresh liquid scintillator replenishment speed of a second delivery pump according to the degradation of the liquid scintillator performance, and correcting the beam current intensity measurement results. The liquid scintillator performance is displayed in real time on a PC. Taking advantage of the similar detection performance of liquid scintillator to that of plastic scintillator and the fluidity of liquid, the liquid scintillator is used as a detector, the liquid scintillator is driven to circulate by a first delivery pump, and the luminescence performance of the liquid scintillator is measured in real time by the liquid scintillator performance measurement system.

Description

Technical Field

[0001] The invention relates to the technical field of accelerators, in particular to a liquid scintillation measurement method for beam intensity with a large dynamic range using a beam. Background Art

[0002] An accelerator is a device that increases the speed (kinetic energy) of charged particles. Accelerators can be used in nuclear experiments, radiomedicine, radiochemistry, the manufacture of radioisotopes, and non-destructive testing. The energy added to particles is generally above 0.1 MeV. There are many types of accelerators, including cyclotrons, linear accelerators, electrostatic accelerators, particle accelerators, and voltage-doubling accelerators. Monitoring the intensity of the particle beam generated by the accelerator is one of the key technologies that determine the safety and reliability of the accelerator's expanded applications. Traditional beam monitoring methods generally use pulse or DC current monitoring equipment such as beam transformers (CTs) and Faraday cups. The applicable beam intensity measurement range is generally within 10 6 p / s, so it is widely used in the measurement of particle beam intensity with large beam intensity such as accelerator main beam (generally within 10 10～16 p / s), and the technology is relatively mature.

[0003] However, the actual application of accelerator technology is more realized on the application beam of the accelerator. These application beams only need to separate a small part of the beam from the accelerator main beam to complete the corresponding task. Therefore, the beam intensity is relatively low, generally around 10 7 For beam intensities below p / s, particle physics detection methods are typically used to directly measure particles in the beam using gas detectors such as ionization chambers, semiconductor detectors such as silicon microstrip detectors, and scintillator detectors such as plastic scintillators. Plastic scintillators offer irreplaceable advantages in accelerator beam applications due to their short decay time, high energy resolution, relative insensitivity to gamma radiation, and excellent n-gamma resolution. With the increasing application of accelerator technology in fields such as medicine, chemistry, and biology, the range of beam intensities required for experiments using applied beams is becoming increasingly wider, and the upper limit of beam intensities is increasing. Consequently, the upper limit of beam intensities that beam intensity measurement equipment must withstand is also increasing.

[0004] In the existing technology, taking plastic scintillators as an example, the higher the beam intensity measured by the detector, the stronger their irradiation effect, which will cause the detector's detection capability to decline faster, and in turn lead to a higher frequency of manual replacement of scintillators. However, if plastic scintillators are used, the steps involved in their replacement are cumbersome. Frequent manual replacement of scintillators at higher beam intensities is unrealistic and uneconomical. Excessive scintillator replacement frequency will greatly increase the time cost of beam operation and maintenance, and also increase the radiation dose of maintenance personnel. Based on this, we propose a liquid scintillator measurement method for a large dynamic range of beam intensities to optimize the existing technology. Summary of the Invention

[0005] The object of the present invention is to provide a liquid scintillation measurement method using a beam with a large dynamic range of beam intensity, so as to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A liquid scintillation measurement method using a large dynamic range of beam intensity includes a liquid scintillation circulation monitoring device, the liquid scintillation circulation monitoring device including a PMT, a detection cavity, a first delivery pump, a liquid scintillation performance measurement system, a PLC controller, a PC, a second delivery pump, a replenishment pipeline, a fresh liquid scintillation source device, and a circulation pipeline. The method steps are as follows:

[0008] S1: Prepare liquid scintillator in the liquid scintillation cycle monitoring device;

[0009] S2: The liquid scintillator is circulated through the liquid scintillator circulation monitoring device while measuring the beam intensity and replenishing fresh liquid scintillator;

[0010] S3: The measurement results of the liquid scintillator performance measurement system are read through the PLC controller. The fresh liquid scintillator replenishment rate of the second delivery pump is changed according to the decline in liquid scintillator performance, and the beam intensity measurement results are corrected. The liquid scintillator performance is displayed in real time on the PC.

[0011] As a further solution of the present invention: in S1, firstly, the detection cavity in the liquid scintillator circulation monitoring device is filled with liquid scintillator and placed in the beam channel.

[0012] As a further solution of the present invention: in S2, the beam passes through the detection cavity, and scintillation light is generated therein when the beam passes through, and a signal is output in the PMT to measure the beam intensity, and the first delivery pump drives the liquid scintillator to circulate in the circulation pipe and the detection cavity. During the circulation process, when the liquid scintillator passes through the liquid scintillator performance measurement system, the luminescence performance of the liquid scintillator is calibrated in real time by a standard radioactive source and a PMT. The standard radioactive source and the PMT are installed on the detection cavity and offset from the beam channel. If the luminescence performance decreases, the second delivery pump is used to replenish fresh liquid scintillator in the fresh liquid scintillator source device into the circulation pipe through the replenishing pipe to replenish fresh liquid scintillator, thereby ensuring the stability of the performance of the liquid scintillator.

[0013] As a further solution of the present invention: in the above S3, the measured data is fed back to the PLC controller through the liquid scintillator performance measurement system, and then fed back to the PC end by the PLC controller. The PC end feeds back the measured liquid scintillator performance through the PLC controller, and the beam intensity is obtained by measuring the PMT in the detection cavity (1). The fresh liquid scintillator replenishment speed of the second delivery pump is changed according to the degradation of the liquid scintillator performance, and the measured beam intensity is corrected in time.

[0014] As a further solution of the present invention: the liquid scintillation performance measurement system is used to calibrate the luminescence performance of liquid scintillation liquid in real time, one end of the circulation pipe passes through the upper part of one side of the detection cavity and is connected to its interior, the other end of the circulation pipe passes through the lower part of the other side of the detection cavity and is connected to its interior, the first delivery pump and the liquid scintillation performance measurement system are both installed on the circulation pipe, one end of the supplementary pipe is connected to the interior of the fresh liquid scintillation source device, the other end of the supplementary pipe is connected to the interior of the circulation pipe, and the second delivery pump is installed on the supplementary pipe.

[0015] As a further solution of the present invention: the first delivery pump, the liquid scintillator performance measurement system and the second delivery pump are all electrically connected to the PLC controller via wires, the PLC controller is electrically connected to the PC end via wires, and the PMT is electrically connected to the PC end via wires. The control logic of the entire liquid scintillator circulation monitoring device is controlled by the PLC controller, which is responsible for logical operations and issuing control instructions.

[0016] As a further solution of the present invention: the fresh liquid scintillator device contains fresh liquid scintillator, which is used to provide fresh liquid scintillator. The liquid scintillator (LS) is an organic scintillator, and its measurement principle is similar to that of plastic scintillator. When high-energy particles enter the LS, they interact with the molecules in the LS, exciting the LS molecules to undergo transitions and de-excitation, and generating a large number of visible photons. These photons propagate isotropically in the LS, and a portion of them propagate to the photocathode of the PMT (photomultiplier tube) used in conjunction with the LS. The photocathode of the PMT is usually made of an alkali metal with low excitation energy. The photon undergoes a photoelectric effect with the photocathode of the PMT and generates an excited electron, also known as a photoelectron PE. Under the action of the strong electric field inside the PMT, the photoelectron drifts toward the anode, and is multiplied by the dynode or MCP on the anode, and a signal is output at the same time. By performing data analysis and statistics on the output signal, the number of photons generated in the LS or the total energy deposited by the charged particles can be indirectly calculated, and the beam intensity passing through the LS can be further calculated.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. In the present invention, the similar detection performance of liquid scintillator and plastic scintillator and the fluidity of liquid are utilized. Liquid scintillator is used as a detector, and the liquid scintillator is driven to circulate by a first delivery pump. The luminous performance of the liquid scintillator is measured in real time by a liquid scintillator performance measurement system. The fresh liquid scintillator source in the fresh liquid scintillator source device is replenished into the circulation pipeline through a replenishing pipeline by a second delivery pump, and the replenishment amount of fresh liquid scintillator is changed to ensure that the performance of the liquid scintillator is always stable at a high level, and the long-term and stable application of the liquid scintillator under high beam intensity is ensured. In addition, the automatic replenishment of liquid scintillator avoids the many inconveniences caused by frequent manual replenishment of scintillator. It is more convenient to use liquid scintillator instead of plastic scintillator.

[0019] 2. In the present invention, the PLC controller is responsible for logical operations and issuing control instructions, so that the liquid scintillator circulation monitoring device can realize real-time circulation and updating of the liquid scintillator, so that the liquid scintillator can still maintain relatively good detection performance under higher beam intensities, thereby realizing long-term and stable monitoring of the beam intensity of the applied beam in a large dynamic range, ensuring measurement stability and high measurement accuracy, and at the same time reducing the operating and maintenance costs caused by replacing the scintillator. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is an overall schematic diagram of the liquid scintillation cycle monitoring device in the liquid scintillation measurement method using a large dynamic range of beam intensity.

[0021] Figure 2 Flow chart of a method for measuring liquid scintillation using a large dynamic range of beam intensities.

[0022] As shown in the figure: detection chamber 1, first delivery pump 2, liquid scintillation performance measurement system 3, PLC controller 4, PC terminal 5, second delivery pump 6, supplementary pipeline 7, fresh liquid scintillation source device 8, and circulation pipeline 9. DETAILED DESCRIPTION

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0024] See also Figures 1-2 In an embodiment of the present invention, a liquid scintillator measurement method using a large dynamic range of beam intensity includes a liquid scintillator circulation monitoring device. The liquid scintillator circulation monitoring device includes a PMT, a detection chamber 1, a first delivery pump 2, a liquid scintillator performance measurement system 3, a PLC controller 4, a PC 5, a second delivery pump 6, a replenishment pipeline 7, a fresh liquid scintillator source device 8, and a circulation pipeline 9. The method steps are as follows:

[0025] S1: Prepare liquid scintillator in the liquid scintillation cycle monitoring device;

[0026] S2: The liquid scintillator is circulated through the liquid scintillator circulation monitoring device while measuring the beam intensity and replenishing fresh liquid scintillator;

[0027] S3: The measurement results of the liquid scintillator performance measurement system are read through the PLC controller. The fresh liquid scintillator replenishment rate of the second delivery pump is changed according to the decline in liquid scintillator performance, and the beam intensity measurement results are corrected. The liquid scintillator performance is displayed in real time on the PC.

[0028] In S1 , the detection cavity 1 in the liquid scintillator circulation monitoring device is first filled with liquid scintillator and placed in the beam channel.

[0029] In S2, the beam passes through the detection cavity 1, and scintillation light is generated therein and a signal is output in the PMT to measure the beam intensity. The first delivery pump 2 drives the liquid scintillator to circulate in the circulation pipe 9 and the detection cavity 1. During the circulation process, when the liquid scintillator passes through the liquid scintillator performance measurement system 3, the luminescence performance of the liquid scintillator is calibrated in real time by a standard radioactive source and a PMT. The standard radioactive source and the PMT are installed on the detection cavity 1 and offset from the beam channel. If the luminescence performance decreases, the second delivery pump 6 works to replenish the fresh liquid scintillator in the fresh liquid scintillator source device 8 into the circulation pipe 9 through the replenishment pipe 7 to replenish the fresh liquid scintillator, thereby ensuring the stability of the liquid scintillator performance.

[0030] In S3, the measured data is fed back to the PLC controller 4 through the liquid scintillator performance measurement system 3, and then fed back to the PC terminal 5 by the PLC controller 4. The PC terminal 5 feeds back the measured liquid scintillator performance through the PLC controller 4, and obtains the beam intensity by measuring the PMT in the detection cavity (1). The fresh liquid scintillator replenishment speed of the second delivery pump 6 is changed according to the degradation of the liquid scintillator performance, and the measured beam intensity is corrected in time.

[0031] The liquid scintillation performance measurement system 3 is used to calibrate the luminescence performance of the liquid scintillation liquid in real time. One end of the circulation pipe 9 passes through the upper part of one side of the detection cavity 1 and is connected to its interior. The other end of the circulation pipe 9 passes through the lower part of the other side of the detection cavity 1 and is connected to its interior. The first delivery pump 2 and the liquid scintillation performance measurement system 3 are both installed on the circulation pipe 9. One end of the supplementary pipe 7 is connected to the interior of the fresh liquid scintillation source device 8, and the other end of the supplementary pipe 7 is connected to the interior of the circulation pipe 9. The second delivery pump 6 is installed on the supplementary pipe 7.

[0032] The first delivery pump 2, the liquid scintillator performance measurement system 3, and the second delivery pump 6 are all electrically connected to the PLC controller 4 via wires. The PLC controller 4 is electrically connected to the PC terminal 5 via wires. The PMT is electrically connected to the PC terminal 5 via wires. The control logic of the entire liquid scintillator circulation monitoring device is controlled by the PLC controller 4, which is responsible for logical operations and issuing control instructions.

[0033] The fresh liquid scintillator device 8 contains fresh liquid scintillator, which is used to provide fresh liquid scintillator. The liquid scintillator (LS) is an organic scintillator, and its measurement principle is similar to that of plastic scintillator. When high-energy particles enter the LS, they will interact with the molecules in the LS, excite the LS molecules to undergo transitions and de-excitation, and generate a large number of visible photons. These photons propagate isotropically in the LS, and some of them will propagate to the photocathode of the PMT (photomultiplier tube) used in conjunction with the LS. The photocathode of the PMT is usually made of alkali metals with low excitation energy. The photon and the photocathode of the PMT produce a photoelectric effect and generate an excited electron, which is also called a photoelectron PE. Under the action of the strong electric field inside the PMT, the photoelectron drifts toward the anode and achieves signal multiplication on the anode through the dynode or MCP, and outputs a signal at the same time. By performing data analysis and statistics on the output signal, it is possible to indirectly calculate the number of photons generated in the LS or the total energy deposited by the charged particles, and then calculate the beam intensity passing through the LS.

[0034] There is a certain probability that the incident high-energy particles will change the properties of the LS molecules with which they interact, resulting in a decrease in the light yield and light propagation coefficient of the LS. This is the radiation damage effect of high-energy particles in the scintillator. When the beam intensity is very high, the radiation damage to the scintillator can cause a significant decrease in scintillator performance in a very short time. At this time, the scintillator must be replaced to ensure the performance of the detector. However, if a plastic scintillator is used, the steps involved in its replacement are cumbersome. Frequent manual replacement of the scintillator at higher beam intensities is unrealistic and uneconomical. The liquid scintillator measurement method of the present invention using a large dynamic range of beam intensities can avoid the above troubles by using liquid scintillator instead of plastic scintillator.

[0035] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A liquid scintillation measurement method using a large dynamic range of beam intensity, comprising a liquid scintillation circulation monitoring device, the liquid scintillation circulation monitoring device comprising a PMT, a detection cavity (1), a first delivery pump (2), a liquid scintillation performance measurement system (3), a PLC controller (4), a PC terminal (5), a second delivery pump (6), a supplementary pipeline (7), a fresh liquid scintillation source device (8) and a circulation pipeline (9), characterized in that: The method steps are as follows: S1: preparing a liquid scintillator in a liquid scintillation circulation monitoring device, first filling a detection cavity (1) in the liquid scintillation circulation monitoring device with the liquid scintillator and placing the detection cavity (1) in the liquid scintillator in a beam channel; S2: The liquid scintillator is circulated by the liquid scintillator circulation monitoring device while the beam intensity is measured, and fresh liquid scintillator is replenished; the beam passes through the detection cavity (1), scintillation light is generated therein when the beam passes through, and the beam intensity is measured by the PMT, and the first delivery pump (2) drives the liquid scintillator to circulate in the circulation pipe (9) and the detection cavity (1). During the circulation process, when the liquid scintillator passes through the liquid scintillator performance measurement system (3), the luminous performance of the liquid scintillator is calibrated in real time by the standard radioactive source and the PMT. The standard radioactive source and the PMT are installed on the detection cavity (1) and are offset from the beam channel. If the luminous performance decreases, the fresh liquid scintillator in the fresh liquid scintillator source device (8) is replenished into the circulation pipe (9) through the replenishment pipe (7) by the second delivery pump (6), and fresh liquid scintillator is replenished, thereby ensuring the stability of the performance of the liquid scintillator; S3: The measurement results of the liquid scintillator performance measurement system are read through the PLC controller. The fresh liquid scintillator replenishment rate of the second delivery pump is changed according to the decline in liquid scintillator performance, and the beam intensity measurement results are corrected. The liquid scintillator performance is displayed in real time on the PC.

2. The liquid scintillation measurement method using a large dynamic range of beam intensity according to claim 1, characterized in that: In the S3, the measured data is fed back to the PLC controller (4) through the liquid scintillator performance measurement system (3), and then fed back to the PC end (5) by the PLC controller (4). The PC end (5) feeds back the measured liquid scintillator performance through the PLC controller (4), and obtains the beam intensity by measuring the PMT in the detection cavity (1). The fresh liquid scintillator replenishment speed of the second delivery pump (6) is changed according to the degradation of the liquid scintillator performance, and the measured beam intensity is corrected in time.

3. The liquid scintillation measurement method using a large dynamic range of beam intensity according to claim 1, characterized in that: The liquid scintillation performance measurement system (3) is used to calibrate the luminous performance of liquid scintillation liquid in real time. One end of the circulation pipe (9) passes through the upper part of one side of the detection cavity (1) and is connected to the interior thereof. The other end of the circulation pipe (9) passes through the lower part of the other side of the detection cavity (1) and is connected to the interior thereof. The first delivery pump (2) and the liquid scintillation performance measurement system (3) are both installed on the circulation pipe (9). One end of the supplementary pipe (7) is connected to the interior of a fresh liquid scintillation source device (8), and the other end of the supplementary pipe (7) is connected to the interior of the circulation pipe (9). The second delivery pump (6) is installed on the supplementary pipe (7).

4. The liquid scintillation measurement method using a large dynamic range of beam intensity according to claim 1, characterized in that: The first delivery pump (2), the liquid scintillator performance measurement system (3), and the second delivery pump (6) are all electrically connected to a PLC controller (4) via wires, the PLC controller (4) is electrically connected to a PC terminal (5) via wires, and the PMT is electrically connected to the PC terminal (5) via wires. The control logic of the entire liquid scintillator circulation monitoring device is controlled by the PLC controller (4), which is responsible for logical operations and issuing control instructions.

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