An on-line device for identifying radionuclides in water and measuring total alpha / beta specific activity

Abstract

The application discloses a device for recognizing radionuclide in water and measuring total specific activity of alpha and beta radiation in water on line, which comprises a water container, a water inlet and a water outlet arranged on the water container and communicated with the inside of the water container, a scintillator fiber array detector fixedly arranged in the water container, a back-Compton gamma spectrometer arranged on the water container, a sealing channel arranged on the shell of the water container for penetrating power lines and signal lines, and a processor connected with the scintillator fiber array detector and the back-Compton gamma spectrometer through the signal lines. The device can be connected with water flow by arranging the water container and the scintillator fiber array detector in the water container, and the total specific activity of alpha and beta radiation in water can be directly given by the scintillator fiber array detector through pulse signal counting, so that the total specific activity of alpha and beta radiation in water can be measured on line, and the radionuclide in water flow can be recognized by the back-Compton gamma spectrometer synchronously. The measuring process is simple and convenient, and the device has high practicability.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of detection, and particularly relates to a device for recognizing radionuclides in water and measuring total alpha / beta specific activity on line. BACKGROUND

[0002] The recognition of radionuclides in water and the monitoring of total specific activity are important measures for ensuring the safety of water resources. The radionuclides in natural water mainly come from the uranium series, the thorium series, the actinouranium series and potassium-40 in the stratum; among them, the uranium series, the thorium series and the actinouranium series mainly radiate alpha rays, and potassium-40 mainly radiates beta rays, in addition, these radionuclides will also radiate characteristic gamma rays in the process of decay; in recent years, with the continuous development of nuclear energy and other nuclear technologies, facilities using nuclear energy and nuclear technologies may release the above-mentioned radionuclides and other radionuclides, which will affect water resources through natural circulation; therefore, the recognition of radionuclides in water and the monitoring of alpha / beta specific activity are paid more and more attention.

[0003] At present, the recognition of radionuclides in water and the monitoring of alpha / beta specific activity are mainly carried out by direct or indirect measurement using liquid scintillator detectors, alpha / beta special measuring instruments, high-purity germanium semiconductor detectors and other equipment; for example, the main steps of measurement using a liquid scintillator detector or an alpha / beta special measuring instrument include sampling, concentration, transfer, washing, burning, ashing, weighing and sample preparation and other cumbersome processes, which not only complicate the measurement process and easily contaminate the sample, but also can only measure the alpha / beta total specific activity and cannot realize the recognition of radionuclides; for another example, the main steps of measurement using a high-purity germanium semiconductor detector also include sampling, concentration, transfer, washing, burning, ashing, weighing, sample preparation and other cumbersome processes, and this method indirectly gives the alpha / beta total specific activity by measuring the characteristic gamma ray spectrum of the radionuclides in the prepared sample through characteristic gamma ray activity measurement and radionuclide identification; the main shortcomings of these measurement methods are that the measurement process is complex, the measurement time is long, sampling measurement is required, and online monitoring cannot be realized. SUMMARY

[0004] The purpose of the present application is to provide a device for recognizing radionuclides in water and measuring total alpha / beta specific activity on line, so as to solve the problems in the background art.

[0005] In order to achieve the above object, the present application provides the following technical scheme: a water container is provided with a water inlet and a water outlet which are in communication with the inside of the water container, and a scintillator fiber array detector is fixedly arranged in the inside of the water container; the scintillator fiber array detector comprises a scintillator fiber array, a packaging flange and a first photomultiplier tube, the scintillator fiber array is bundled in a shuttle shape by a plurality of scintillator fibers, the two ends of the scintillator fiber array are respectively coupled with the first photomultiplier tube, and the two ends of the scintillator fiber array are packaged by the packaging flange and sealing glue; the water container is further provided with an inverse Compton gamma spectrometer for identifying radionuclides; a sealing channel for penetrating the power line and the signal line of the scintillator fiber array, the first photomultiplier tube and the inverse Compton gamma spectrometer is arranged on the shell of the water container; and the scintillator fiber array detector and the inverse Compton gamma spectrometer are connected with a processor through the signal line.

[0006] Preferably, the inverse Compton gamma spectrometer comprises a LaBr3 scintillator detector and a plurality of BGO scintillator detectors which are uniformly distributed around the LaBr3 scintillator detector, and a second photomultiplier tube is fixedly connected to the end of each BGO scintillator detector; and an aluminum thin-wall gamma ray window is fixedly arranged below the inverse Compton gamma spectrometer.

[0007] The BGO scintillator detector scatters gamma pulse signals and the LaBr3 scintillator detector outputs characteristic gamma spectra in the inverse coincidence mode, so as to lower the Compton plateau on the characteristic gamma spectrum and make the characteristic gamma peak more obvious, which is more conducive to identifying radionuclides in water through the characteristic gamma peak.

[0008] Preferably, the detection end of the inverse Compton gamma spectrometer is arranged in the inside of the water container.

[0009] The detection end of the inverse Compton gamma spectrometer is arranged in the inside of the water container, so as to maximize the collection of characteristic gamma rays emitted by radionuclides in water.

[0010] Further, a lead shielding layer is arranged on the outer layer of the water container.

[0011] The lead shielding layer absorbs rays in the environment to form a low-background measurement environment, so as to reduce the influence of environmental rays on the measurement results.

[0012] Preferably, the sealing glue is epoxy resin, and the inside of the sealing channel is sealed by the epoxy resin.

[0013] The epoxy resin has strong adhesion, wear resistance and chemical corrosion resistance, and good adhesion, which can effectively improve the service life of the device.

[0014] The system energy calibration method of the above-mentioned radionuclide identification and alpha / beta total specific activity online measurement device is as follows:

[0015] S1. Fill the water container with high-purity water, measure the background count rate by using the scintillation fiber array detector, and measure the background gamma spectrum by using the inverse Compton gamma spectrometer;

[0016] S2. Prepare an aqueous solution containing different specific activities of americium-241 and potassium chloride by using high-purity water, inject the solution into the water container, perform system energy calibration, and obtain a calibration curve of the scintillation fiber array detector system count rate and the total alpha / beta specific activity;

[0017] S3. After the completion of system energy calibration, inject high-purity water into the water container for multiple cleanings.

[0018] Compared with the prior art, the present application has the following beneficial effects:

[0019] 1. The water container is provided, and the scintillation fiber array detector is arranged inside the water container. The device can be connected to a water flow. The water flows into the container from the water inlet of the water container and flows out from the water outlet of the water container. The alpha / beta rays emitted by the radioactive nuclides in the water directly act on the scintillation fiber, causing the scintillation fiber to emit light. The photons are conducted to the first photomultiplier tube through the scintillation fiber. The electrons are generated in the cathode of the first photomultiplier tube through the photoelectric effect. The electrons are multiplied in the first photomultiplier tube and output pulse signals from the anode. The total alpha / beta specific activity in the water is directly given by recording the count of the pulse signals, thereby realizing online measurement of the total alpha / beta specific activity in the water. The present application can also identify the radioactive nuclides in the water flowing through the water container by using the inverse Compton gamma spectrometer.

[0020] 2. The scuttle-shaped scintillation fiber array is provided. The central part of the scintillation fiber array is raised and loose, so that the water can easily enter the gap between the scintillation fibers, thereby effectively improving the accuracy of the measurement of the total alpha / beta specific activity in the water. BRIEF DESCRIPTION OF DRAWINGS

[0021] Fig. 1 is a front view of the water radioactive nuclide identification and alpha / beta specific activity online measurement device provided by the embodiment of the present application;

[0022] Fig. 2 is a schematic view of the arrangement structure of the LaBr3 scintillation detector and the BGO scintillation detector provided by the embodiment of the present application;

[0023] In the figure, 1 is a water container, 2 is a scintillation fiber array detector, 3 is an inverse Compton gamma spectrometer, 11 is a lead shielding layer, 12 is a water inlet, 13 is a water outlet, 14 is a sealing channel, 21 is a scintillation fiber array, 22 is a packaging flange, 23 is a first photomultiplier tube, 31 is a LaBr3 scintillation detector, 32 is a BGO scintillation detector, 33 is a second photomultiplier tube, and 34 is an aluminum thin-walled gamma ray window. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Please see Figs. 1-2 The present invention provides a technical solution: an online measurement device for identifying radionuclides in water and measuring the total α / β radioactivity, including a water container 1, the water container 1 being wrapped with a lead shielding layer 11 to reduce the influence of environmental radiation on the interior of the water container 1, the water container 1 being provided with an inlet 12 and an outlet 13 communicating with the interior of the water container 1, and a scintillator fiber optic array detector 2 being fixedly installed inside the water container 1.

[0026] The scintillator fiber array detector 2 includes: a scintillator fiber array 21, a packaging flange 22, and a first photomultiplier tube 23. The scintillator fiber array 21 is composed of multiple scintillator fibers bound together in a shuttle shape. The two ends of the scintillator fiber array 21 are respectively coupled to the first photomultiplier tube 23, and the two ends of the scintillator fiber array 21 are packaged by the packaging flange 22 and sealed with epoxy resin. The water container 1 is also equipped with an anti-Compton gamma spectrometer 3 for identifying radionuclides. The detection end of the anti-Compton gamma spectrometer 3 is located inside the water container 1. The shell of the water container 1 is provided with a sealed channel 14 for the power lines and signal lines of the scintillator fiber array 21, the first photomultiplier tube 23, and the anti-Compton gamma spectrometer 3 to pass through. After the power lines and signal lines pass through the sealed channel 14, the sealed channel 14 is sealed by filling with epoxy resin. The scintillator fiber array 21, the first photomultiplier tube 23, and the anti-Compton gamma spectrometer 3 are connected to the processor through the signal lines.

[0027] In this invention, the measurement principle of the scintillation fiber array detector 2 is as follows: the α / β rays emitted by the radioactive nuclide in the water sample interact with the scintillation fiber to cause light emission. The emitted photons are transmitted through the fiber to the photocathode of the first photomultiplier tube 23, where electrons are generated through the photoelectric effect. The electrons are multiplied in the first photomultiplier tube 23 and output pulse signals from its anode. The total specific activity of α / β in the water is measured by recording the pulse signal count through the processor. Its measurement sensitivity can reach 0.1 Bq / L.

[0028] The anti-Compton gamma spectrometer 3 includes a LaBr3 scintillator detector 31 and multiple BGO scintillator detectors 32 evenly distributed around the LaBr3 scintillator detector 31, with a second photomultiplier tube 33 fixedly connected to the end of each BGO scintillator detector 32. The anti-Compton gamma spectrometer 3 identifies radionuclides in water by measuring the characteristic gamma-ray energy spectrum emitted by radionuclides in water. The gamma pulse signal scattered by the BGO scintillator detector 32 anti-coincides with the gamma pulse signal of the LaBr3 scintillator detector 31 to output a characteristic gamma energy spectrum. The purpose is to suppress the Compton plateau on the characteristic gamma energy spectrum, making the characteristic gamma peak more prominent and more conducive to identifying radionuclides in water through the characteristic gamma peak.

[0029] An aluminum thin-walled gamma-ray window 34 is fixedly installed below the anti-Compton gamma-ray spectrometer 3. The aluminum thin-walled gamma-ray window 34 isolates water flow to prevent water from corroding the anti-Compton gamma-ray spectrometer 3, while not affecting the radiation, allowing the radiation to exit through this window. Aluminum is used because aluminum has a low atomic number and will not have too much shielding effect on gamma rays.

[0030] It should be noted that the anti-Compton gamma spectrometer 3 of this invention requires system energy calibration using multiple standard gamma sources before use. The specific method is as follows:

[0031] 1. Fill water container 1 with high-purity water, measure the background count rate using scintillation fiber array detector 2, and measure the background gamma spectrum using anti-Compton gamma spectrometer 3 so that the background effect can be subtracted during data processing;

[0032] 2. Americium-241 with different specific activities was prepared using high-purity water. 241 Am (α emitter) and potassium chloride (KCl, in which... 40 K is a β emitter) aqueous solution, injected into water container 1, system energy calibration is performed, and the count rate of the scintillation fiber array detector 2 system and the α / β total radioactivity specific activity calibration curve are obtained.

[0033] 3. After calibration, rinse water container 1 multiple times with high-purity water to eliminate impurities. 241 Am and 40 The effect of K residue on the measurement.

[0034] It should be noted that the scintillation fiber, LaBr3 scintillator detector 31, BGO scintillator detector 32, photomultiplier tube and processor in this invention are all commercially available components purchased from the market. Their specific models and specifications need to be selected and determined according to the actual specifications of the device. The selection and calculation method adopts the existing technology in this field, so it will not be described in detail.

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

Claims

1. A device for in-situ radionuclide identification and online measurement of alpha / beta gross specific activity in water, characterized in that: The water container is provided with a water inlet and a water outlet in communication with the inside of the water container, and a scintillator fiber array detector is fixedly arranged in the inside of the water container; the scintillator fiber array detector comprises a scintillator fiber array, a packaging flange and a first photomultiplier tube, the scintillator fiber array is bundled in a shuttle shape by a plurality of scintillator fibers, the scintillator fiber array is coupled to the first photomultiplier tube at two ends respectively, and the two ends of the scintillator fiber array are packaged through the packaging flange and sealing glue; the water container is further provided with an inverse Compton gamma spectrometer for identifying radionuclides; a sealing channel for penetrating the power line and the signal line of the scintillator fiber array, the first photomultiplier tube and the inverse Compton gamma spectrometer is arranged on the shell of the water container; and the scintillator fiber array detector and the inverse Compton gamma spectrometer are connected to a processor through the signal line.

2. The in-situ radionuclide identification and alpha / beta gross activity online measurement device according to claim 1, characterized in that: The inverse Compton gamma spectrometer comprises a LaBr3 scintillator detector and a plurality of BGO scintillator detectors uniformly distributed around the LaBr3 scintillator detector, and a second photomultiplier tube is fixedly connected to the end of each BGO scintillator detector; and an aluminum thin-wall gamma ray window is fixedly arranged below the inverse Compton gamma spectrometer.

3. The in-situ radionuclide identification and alpha / beta gross activity online measurement device according to claim 2, characterized in that: The detection end of the inverse Compton gamma spectrometer is arranged in the inside of the water container.

4. The in-situ radionuclide identification and alpha / beta gross activity online measurement device according to claim 3, characterized in that: A lead shielding layer is arranged on the outer layer of the water container.

5. The in-situ radionuclide identification and alpha / beta gross activity online measurement device of claim 1, wherein: The sealing glue is epoxy resin, and the inside of the sealing channel is sealed by the epoxy resin.

6. A method for system energy calibration using the device for in-situ radionuclide identification and online measurement of alpha / beta gross specific activity according to any one of claims 1 to 5, characterized in that, The method comprises the following steps: S1. Fill the water container with high-purity water, measure the background count rate by using the scintillator fiber array detector, and measure the background gamma spectrum by using the inverse Compton gamma spectrometer; S2. Prepare an aqueous solution containing different specific activities of americium-241 and potassium chloride by using high-purity water, inject the solution into the water container, perform system energy calibration, and obtain a scintillator fiber array detector system count rate and alpha / beta total specific activity calibration curve; S3. After the system energy calibration is completed, inject high-purity water into the water container for multiple times of cleaning.

Images