A radioactive gas detection device based on silicon drift detector

Abstract

The present invention belongs to the field of nuclear radiation protection technology and provides a radioactive gas detection device based on a silicon drift detector. The device comprises a silicon drift detector and a sampling chamber. The sampling chamber has a circular hole at the top. The silicon drift detector is mounted above the sampling chamber with a beryllium window facing the circular hole. The gas to be measured enters the sampling chamber through an inlet pipe, and the gas in the chamber flows out through an outlet pipe. The outlet pipe is arranged offset from the inlet pipe. A preamplifier circuit board and a signal processing board are mounted above the silicon drift detector via a fixed holder. The silicon drift detector, preamplifier circuit board, and signal processing board are disposed within a detector housing, which is fixedly connected to the sampling chamber. A connector is provided at the top of the detector housing. The device can simultaneously calculate radioactive activity and perform nuclide identification. The device uses simulated data and real X-ray data to calculate gamma background counts. The corresponding functions can be achieved using only one detector, greatly improving detector utilization.

Description

Technical Field

[0001] The present invention belongs to the technical field of nuclear radiation protection, and in particular relates to a radioactive gas detection device based on a silicon drift detector. Background Art

[0002] When the fuel elements of a nuclear power plant reactor core are operating normally or damaged, it is inevitable that a small amount of radioactive fission products will penetrate into the primary coolant circuit through the cracks of the fuel elements. When a leak occurs in the primary circuit, these radioactive fission products will easily enter the air and form a radioactive gaseous distribution (inert gas, aerosol, iodine) in the sealed containment. When the reactor containment is shut down, relevant professionals need to enter the containment to perform necessary maintenance and inspection work. Therefore, monitoring the radioactivity in the air in the containment is an important measure to protect relevant personnel, maintain the safety of the nuclear power plant, and ensure the normal operation of the nuclear power plant. This requires the installation of an airborne radioactivity monitoring system to track and monitor various radioactivity indicators in the air in the containment so as to be ready to respond to various possible radioactive leakage incidents in the containment at any time.

[0003] for 85 Kr and 133 Monitoring radioactive gases like Xe is currently performed by detecting decaying beta particles. However, beta decay is often accompanied by gamma rays, and the gamma-ray counts can interfere with measurement results. Furthermore, because the energy spectrum of beta decay is continuous, detectors based on beta decay typically lack nuclide identification capabilities and are unable to distinguish between radioactive nuclides. Summary of the Invention

[0004] To overcome gamma-ray interference with beta-radiation detection and identify radioactive gas nuclides, the present invention provides a radioactive gas detection device based on a silicon drift detector. This device measures low-energy X-ray spectra. By using the peak area of ​​the X-ray peak and the simulated ratio of X-ray counts to gamma-ray counts in the silicon drift detector, the gamma-ray counts are deducted from the X-ray counts themselves to obtain the correct beta-ray count rate. Furthermore, the X-ray peaks provide nuclide information, which can be analyzed to determine the nuclide composition of the radioactive gas.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is: a radioactive gas detection device based on a silicon drift detector, including a silicon drift detector, a sampling chamber, a connector, a preamplifier circuit board and a signal processing board. A circular hole is opened on the top of the sampling chamber, and the silicon drift detector is installed above the sampling chamber, with the beryllium window facing the circular hole. The gas to be measured enters the sampling chamber through the inlet pipe, and the gas in the chamber flows out through the outlet pipe. The outlet pipe and the inlet pipe are staggered. The preamplifier circuit board and the signal processing board are installed above the silicon drift detector through a fixed socket. The silicon drift detector, preamplifier circuit board and signal processing board are arranged in a detector housing, and the detector housing is fixedly connected to the sampling chamber. A connector is provided on the top of the detector housing.

[0006] In the above technical solution, the silicon drift detector adopts an integrated vacuum packaging design, and its power supply, measurement signal, temperature control signal, and temperature feedback signal functions are all input and output by the pins on the back. The pins are connected to the front-end circuit board, and the relevant functions are controlled by the front-end circuit board. The silicon drift detector contains a temperature sensor inside, and the temperature information is output to the outside through the relevant pins, the front-end circuit board and the signal processing board in sequence.

[0007] In the above technical solution, the air inlet pipe is located at the upper middle part of the sampling chamber, and the air outlet pipe is located at the lower middle part of the sampling chamber, and is staggered with the air inlet pipe.

[0008] In the above technical solution, the preamplifier circuit board supplies power to the silicon drift detector, controls the temperature of the silicon drift detector, and receives the temperature feedback signal. The preamplifier circuit board collects the pulse signal given by the silicon drift detector, performs shaping amplification, and samples the energy spectrum information, and outputs the obtained energy spectrum information to the signal processing board. The signal processing board processes the energy spectrum information and counting information, analyzes and gives the radioactive gas activity and nuclide category, and outputs the information to the host computer through the connector.

[0009] The above-mentioned radioactive gas activity measurement means that the detection device of the present invention can provide the activity concentration information of the gas to be measured and can be expressed in Bq / L and Bq / m 3 Output the calculation results in equal units.

[0010] The above-mentioned nuclide category identification means that the detection device of the present invention can provide the type of radioactive nuclides in the gas to be detected and output nuclide information.

[0011] This detection device adopts a sampling monitoring method. The gas to be measured enters the sampling chamber of the detection device through a sampling pipeline. The beryllium window of the silicon drift detector faces the sampling chamber. When the radioactive gas enters the cavity and undergoes β decay, the decaying electrons enter the sensitive volume of the detector through the beryllium window, deposit energy, and are recorded.

[0012] Silicon drift detectors are suitable for measuring low-energy X-rays and charged particles. Therefore, the preamplifier circuit board parameters are configured to keep the detector's energy measurement range below 50 keV. X-ray and gamma-ray counts associated with beta decay also generate corresponding counts. Low-energy X-rays in the keV range form well-resolved characteristic peaks in the beta spectrum. The energy of these characteristic peaks varies for different nuclides, and the ratio of the peak area to the gamma counts also varies. This ratio can be calculated using simulations. The signal processing board processes the energy spectrum to determine the actual beta count rate, which can then be used to calculate the radioactivity and radionuclide type of the chamber gas.

[0013] Compared with the prior art, the detection device of the present invention has the following beneficial effects:

[0014] 1. This device uses X-ray characteristic peaks to calculate radioactivity and identify nuclides at the same time.

[0015] 2. This device can calculate the gamma background count using simulated data and real X-ray data, and only one detector is needed to achieve the corresponding function, which greatly improves the detector utilization rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the overall structure of the detection device of the present invention.

[0017] In the figure: 1. Inlet pipe, 2. Outlet pipe, 3. Sampling chamber, 4. Silicon drift detector, 5. Preamplifier circuit board, 6. Signal processing board, 7. Fixed card holder, 8. Detector housing, 9. Connector. DETAILED DESCRIPTION

[0018] To make the above-mentioned objects, features, and advantages of the present invention more readily apparent, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. The following description sets forth numerous specific details to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art may make similar modifications without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0019] It should be noted that when an element is referred to as being “mounted on” another element, it may be directly on the other element or there may be an element located in between.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0021] like Figure 1 As shown, an embodiment of the present invention provides a radioactive gas detection device based on a silicon drift detector. This device uses energy spectrum analysis to eliminate X-ray and gamma-ray miscounts and achieve nuclide identification. The detection device includes a silicon drift detector 4, a sampling chamber 3, an inlet pipe 1, an outlet pipe 2, a preamplifier circuit board 5, a signal processing board 6, a mounting bracket 7, a detector housing 8, and a connector 9.

[0022] In the above embodiment:

[0023] The gas to be measured enters the sampling chamber 3 through the air inlet pipe 1 , and the air inlet pipe 1 is located in the upper middle part of the sampling chamber 3 .

[0024] The gas in the chamber flows out through the outlet pipe 2 , which is located in the lower middle part of the sampling chamber 3 and is staggered with the inlet pipe 1 .

[0025] The sampling chamber 3 is made of stainless steel and is connected to the inlet pipe 1 and the outlet pipe 2 by welding, ensuring good airtightness at the interface. A circular hole is opened on the top of the sampling chamber 3. When the silicon drift detector 4 is installed, the beryllium window should be facing the circular hole.

[0026] The silicon drift detector 4 is a vacuum-encapsulated, integrated detection module. Its power supply, measurement signal, temperature control signal, and temperature feedback signal are all input and output via pins on the back. These pins are connected to the preamplifier circuit board 5, and these functions are controlled by the preamplifier circuit board 5. The silicon drift detector 4 contains an internal temperature sensor, and temperature information is output through the relevant pins, the preamplifier circuit board 5, and the signal processing board 6.

[0027] The preamplifier circuit board 5 supplies power to the silicon drift detector 4, controls its temperature, and receives temperature feedback signals. Furthermore, the preamplifier circuit board 5 primarily collects pulse signals from the silicon drift detector 4, performs shaping and amplification, and samples energy spectrum information. The resulting energy spectrum information is then fed into the signal processing board 6 for further processing.

[0028] The signal processing board 6 processes the energy spectrum information and the counting information, analyzes and provides information such as the radioactive gas activity and nuclide type, and outputs the information to the host computer through the connector 9.

[0029] The front-end circuit board 5 and the signal processing board 6 are mounted on the silicon drift detector 4 through the fixed card holder 7 .

[0030] The detector housing 8 , the silicon drift detector 4 , the preamplifier circuit board 5 and the signal processing board 6 are arranged in the detector housing 8 , and the detector housing 8 is connected to the sampling chamber 3 using fastening screws.

[0031] Connector 9: A connector 9 is provided on the top of the detector housing 8 for connecting the detection device to the host computer.

[0032] The contents not described in detail in this specification belong to the prior art known to those skilled in the art.

[0033] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements 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 radioactive gas detection device based on a silicon drift detector, characterized in that: It includes a silicon drift detector, a sampling chamber, an air inlet pipe, an air outlet pipe, a connector, a front-end circuit board and a signal processing board. A circular hole is opened on the top of the sampling chamber. The silicon drift detector is installed above the sampling chamber. The beryllium window is opposite to the circular hole. The gas to be measured enters the sampling chamber from the air inlet pipe, and the gas in the chamber flows out from the air outlet pipe. The air outlet pipe and the air inlet pipe are staggered. The front-end circuit board and the signal processing board are installed above the silicon drift detector through a fixed base. The silicon drift detector, the front-end circuit board and the signal processing board are arranged in a detector housing. The detector housing is fixedly connected to the sampling chamber. A connector is provided on the top of the detector housing. The detection device adopts a sampling monitoring method. The gas to be measured Gas enters the sampling chamber of the detection device through a sampling pipeline. The beryllium window of the silicon drift detector faces the sampling chamber. When radioactive gas enters the cavity and undergoes β decay, the decaying electrons enter the sensitive volume of the detector through the beryllium window, deposit energy, and are recorded. The X-rays and γ-rays produced by the β decay will produce corresponding counts. Through the peak area of ​​the X-ray peak and the simulated ratio of X-ray counts to γ-ray counts in the silicon drift detector, the γ-ray counts and the X-ray counts themselves are deducted to obtain the correct β-ray counting rate. At the same time, the X-ray peak can provide nuclide information, and after analysis, the nuclide composition in the radioactive gas can be obtained.

2. The radioactive gas detection device based on silicon drift detector according to claim 1, characterized in that: The silicon drift detector adopts an integrated vacuum packaging design. Its power supply, measurement signal, temperature control signal, and temperature feedback signal functions are all input and output by pins on the back. The pins are connected to the front-end amplifier circuit board, and the relevant functions are controlled by the front-end amplifier circuit board. The silicon drift detector contains a temperature sensor inside, and the temperature information is output to the outside through the relevant pins, the front-end amplifier circuit board and the signal processing board in sequence.

3. The radioactive gas detection device based on silicon drift detector according to claim 1, characterized in that: The air inlet pipe is located at an upper middle position of the sampling chamber, and the air outlet pipe is located at a lower middle position of the sampling chamber, and is staggered with the air inlet pipe.

4. The radioactive gas detection device based on silicon drift detector according to claim 1, characterized in that: The preamplifier circuit board supplies power to the silicon drift detector, controls the temperature of the silicon drift detector, and receives temperature feedback signals. The preamplifier circuit board collects the pulse signal provided by the silicon drift detector, performs shaping amplification, and samples energy spectrum information, and outputs the obtained energy spectrum information to the signal processing board. The signal processing board processes the energy spectrum information and counting information, analyzes and provides the radioactive gas activity and nuclide category, and outputs the information to the host computer through a connector.

Images