System and method for detecting purity of deuterated diborane gas in boronizing system of fusion device

Abstract

The invention discloses a deuterated diborane gas purity detection system and method in a boronizing system of a fusion device, and belongs to the technical field of nuclear fusion, and the system comprises a deuterated diborane gas cylinder, a flow control valve, a vacuum test chamber, a vacuum gauge tube, a quadrupole mass spectrometer, a vacuum pumping unit and a tail gas processor. According to the invention, the vacuum degree in the vacuum test chamber is pumped to 10 <-6 > Pa by using the vacuum pumping unit, and the vacuum test chamber is controlled in a stable state; then opening a flow control valve to introduce deuterated diborane into the vacuum test chamber, adjusting the opening degree of the valve, maintaining the vacuum degree in the vacuum test chamber within 10 <-3 > Pa, and finally measuring the molecular weight and concentration of the introduced gas by using a quadrupole mass spectrometer, so as to distinguish the purity of the deuterated diborane and the purity of the hydrodiborane. According to the method, the purity of the deuterated diborane is determined by detecting the difference between the molecular weights of the hydrogen-substituted diborane and the deuterated diborane through the quadrupole mass spectrometer, and a technical support is provided for a fusion device to carry out pure deuterated diborane boronizing wall treatment.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetic confinement nuclear fusion tokamak wall treatment, and mainly relates to a deuterated diborane gas purity detection system and method in a boronization system of a fusion device. Background Art

[0002] In magnetic confinement fusion tokamaks, boron coating is widely used for pre-plasma discharge first-wall treatment due to its strong adsorption capacity for oxygen impurities. A thin boron film is deposited on the first wall of the vacuum chamber via chemical vapor deposition or plasma-assisted deposition, providing optimal first-wall conditions for plasma discharge in real time. This modifies the vacuum chamber wall and reduces impurities from the wall. Currently, many international fusion devices utilize diborane for wall treatment, such as TEXTOR, DIII-D, and ASDEX-U. This achieves stable control of the first-wall state and facilitates the generation of high-parameter plasmas. In contrast, the domestic fully superconducting tokamak (EAST) utilizes carbon-containing carborane (C2B10H12) for wall treatment. While this effectively suppresses recirculation levels, impurity content, and total radiant power during plasma discharge, the carborane used in this treatment already contains hydrogen and carbon, which introduces additional hydrogen and carbon impurities. This ultimately results in a higher hydrogen-to-deuterium ratio and increased sputtering yield of tungsten impurities during plasma discharge. Experiments have found that after boriding, the plasma density and Dα radiation levels are significantly higher than before boriding, and the hydrogen-deuterium ratio increases. This is due to the high hydrogen content in the working gas. During plasma discharge, a large amount of hydrogen is released into the plasma through isotope exchange, resulting in high hydrogen particle recycling after boriding. This makes it difficult to reduce the hydrogen-deuterium ratio below 25%, making it impossible to provide the optimal hydrogen-deuterium ratio conditions for the ion cyclotron heating system that heats a small number of particles. Therefore, it is urgent to develop a boriding wall treatment system based on deuterated diborane as the working gas to achieve a pure boron film on the first wall of the EAST device. However, most of the diborane gas currently available in China is hydrogenated diborane (B2H6), and only some manufacturers can produce deuterated diborane gas (B2D6). Moreover, the purity of deuterated diborane is difficult to measure. Therefore, there is an urgent need to develop a detection system that can distinguish between hydrogenated and deuterated diborane, so as to realize the purity detection of deuterated diborane and provide technical support for the boronization treatment of the first wall of the fusion device. Summary of the Invention

[0003] The purpose of the present invention is to provide a detection system for the purity of deuterated diborane in fusion devices, detect the ratio of deuterated and hydrogenated diborane in diborane gas, avoid the presence of hydrogenated gas in diborane, and use it as a working material for boronization wall treatment to provide good high-purity boron film wall conditions for plasma discharge.

[0004] The present invention is achieved through the following technical solutions:

[0005] The deuterated diborane purity detection system in the boronization system of the fusion device includes a deuterated diborane gas cylinder, a flow control valve, a vacuum test chamber, a vacuum gauge, a quadrupole mass spectrometer, a vacuum pumping unit and an exhaust gas processor; the deuterated diborane gas cylinder is connected to the vacuum test chamber through an exhaust pipe; both ends of the flow control valve are connected to the vacuum test chamber. 6mm stainless steel pipe; one end of the vacuum test chamber is welded to the exhaust pipe, and the other end is connected to the vacuum exhaust unit through an angle valve, and the two sides are respectively connected to the vacuum gauge and the quadrupole mass spectrometer; the vacuum gauge is connected to the CF35 flange port reserved on one side of the vacuum test chamber; the quadrupole mass spectrometer is connected to the CF35 flange port reserved on the other side of the vacuum test chamber; the vacuum exhaust unit is connected to the vacuum test chamber through a KF40 vacuum angle valve, which includes a turbomolecular pump and a mechanical pump; the exhaust processor is connected to a 1 / 2-inch stainless steel pipe with a vacuum shut-off valve, including a two-stage alkaline spray and an exhaust fan.

[0006] Furthermore, the deuterated diborane gas cylinder is a stainless steel cylinder with an internal pressure greater than 12 MPa, which is used to store and provide a deuterated diborane sample gas source during testing.

[0007] Furthermore, the flow control range of the flow control valve is 5.0×10 -6 ~ 1.25×10 3 mbar·L / s, flow rate adjustment scale value is 1.3×10 -9 mbar·L / s, working pressure range is 1.0×10 -8 mbar~2.5 bar, used for flow control and regulation of deuterated diborane gas cylinders and back-end vacuum test chambers.

[0008] Furthermore, the vacuum test chamber is a stainless steel cylinder; one end of which is welded to the exhaust pipe, one end is provided with a KF40 flange port, and both sides are provided with CF35 flange ports.

[0009] Furthermore, the vacuum gauge range is 10 -8 ~10 5 Pa, and then connect a vacuum gauge to display the vacuum reading for real-time monitoring of the vacuum changes in the chamber.

[0010] Furthermore, the working range of the quadrupole mass spectrometer should be within the vacuum range of 10 -3 Below Pa, the molecular weight of diborane is 28 and that of deuterated diborane is 32. The difference in their molecular weights is used to measure the purity of deuterated diborane samples at different flow rates.

[0011] Furthermore, the vacuum pumping unit is connected to the vacuum test chamber via a vacuum angle valve, and the leakage rate of the vacuum angle valve is less than 1.3×10 -7 Pa·L / s The turbomolecular pump has a pumping speed of 200 L / s, and the mechanical pump has a pumping speed of 20 L / s, which are used to provide a vacuum pumping function for the vacuum test chamber.

[0012] Furthermore, the exhaust gas processor is connected to a stainless steel pipe with an inner diameter of 1 / 2 inch, and the vacuum shut-off valve leakage rate is < 1.3×10 -7 Pa·L / s, the whole is in a slightly negative pressure state, the two-stage alkaline spray is continuously sprayed, and the exhaust fan is in the normally open state, which is used to neutralize the exhaust gas of the deuterated diborane sample during and after the test and for subsequent discharge.

[0013] Furthermore, the deuterated diborane gas cylinder has an inner diameter of Φ200 mm, a height of 1500 mm, a volume of 40 L, and an internal pressure greater than 12 MPa. To prevent decomposition of the deuterated diborane sample, it is stored in a frozen or low-temperature environment.

[0014] Furthermore, the vacuum test chamber has an inner diameter of A stainless steel cylinder with a diameter of 100 mm, a wall thickness of 3 mm, and a length of 500 mm has a 6 mm exhaust pipe welded to one end and a KF40 flange port on the other end for connecting to the subsequent exhaust unit; CF35 flange ports are left on both sides for connecting to the subsequent vacuum gauge and quadrupole mass spectrometer.

[0015] Furthermore, the flow control valve is connected to the 6mm stainless steel exhaust line using a sleeve to ensure vacuum tightness. The flow control valve is primarily used to control the flow rate of the deuterated diborane sample and to isolate and connect the deuterated diborane cylinder to the back-end vacuum test chamber. During the deuterated diborane sample test, the flow control valve remains open to control the flow rate of the deuterated diborane sample. At the end of the deuterated diborane sample test, in a high vacuum environment, the flow control valve is closed to isolate the deuterated diborane cylinder from the vacuum test chamber.

[0016] Furthermore, the vacuum gauge and the vacuum test chamber are sealed using a CF35 knife-edge flange and an oxygen-free copper seal. During the vacuum test chamber pumping process, the vacuum gauge remains open, and the vacuum level inside the vacuum test chamber is constantly monitored by a vacuum gauge at the rear.

[0017] Furthermore, the quadrupole mass spectrometer and the vacuum test chamber are sealed with a CF35 knife-edge flange and an oxygen-free copper sealing ring. -3 Pa, the quadrupole mass spectrometer can be turned on to detect the deuterated diborane sample in the vacuum test chamber.

[0018] Furthermore, the turbomolecular pump is mainly used to provide a higher vacuum environment for the vacuum test chamber. The front stage of the turbomolecular pump is equipped with a mechanical pump with a pumping speed of 20L / s. It is connected in series with the turbomolecular pump and is mainly used to provide pumping capacity during the initial pumping of the vacuum test chamber and to start the front stage pump of the molecular pump after the airflow in the vacuum test chamber stabilizes.

[0019] Furthermore, the exhaust gas processor is connected to the exhaust gas emission pipeline, and the stainless steel pipeline and the vacuum shut-off valve are connected and sealed via a threaded connection to ensure the vacuum airtightness requirements of the exhaust gas emission pipeline. The vacuum shut-off valve is mainly used to control the inflow and outflow of exhaust gas and the isolation and connection between the vacuum test chamber and the back-end exhaust gas processor. During and at the end of the deuterated diborane sample testing process, the vacuum shut-off valve remains open; at the end of the exhaust gas treatment, the vacuum shut-off valve is closed to isolate the vacuum test chamber from the back-end exhaust gas processor. The exhaust gas processor includes a two-stage alkaline spray for neutralizing the exhaust gas of the deuterated diborane sample. The back end is connected to the exhaust gas blower; after the exhaust gas is fully treated, it is discharged through the exhaust gas blower.

[0020] Beneficial effects:

[0021] The present invention provides a simple, economical and effective detection system for deuterated diborane purity. It can effectively detect the purity of diborane in boronization, avoid contamination by other impurities in the sample and ensure the safety of future experiments. More importantly, it provides a new type of pure working material for the boronization wall treatment system of fusion devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of the present invention.

[0023] In the figure, 1 is a deuterated diborane gas cylinder; 2 is an exhaust pipe; 3 is a flow control valve; 4 is a vacuum test chamber; 5 is a vacuum gauge; 6 is a quadrupole mass spectrometer; 7 is a vacuum angle valve; 8 is a turbomolecular pump; 9 is a mechanical pump; 10 is an exhaust pipe; 11 is a vacuum shut-off valve; and 12 is an exhaust processor. DETAILED DESCRIPTION

[0024] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. However, the following embodiments are intended only to explain the present invention, and the scope of protection of the present invention should include the entire contents of the claims. Moreover, through the description of the following embodiments, those skilled in the art can fully implement the entire contents of the claims of the present invention.

[0025] like Figure 1As shown, a deuterated diborane purity detection system for a fusion device boronization system includes a deuterated diborane gas cylinder 1, a flow control valve 3, a vacuum test chamber 4, a vacuum gauge 5, a quadrupole mass spectrometer 6, a vacuum pumping unit, and an exhaust gas processor 12. The deuterated diborane gas cylinder 1 is connected to the vacuum test chamber 4 via an exhaust pipe 2; the flow control valve 3 is mounted on the exhaust pipe 2; the vacuum test chamber 4 is the evacuated chamber of the present invention; the vacuum gauge 5 is connected to the vacuum test chamber 4 via a CF35 flange, the rear end of which is connected to a vacuum gauge; the quadrupole mass spectrometer 6 is connected to the vacuum test chamber 4 via a CF35 flange, the rear end of which is connected to a common machine; the vacuum pumping unit is connected to the vacuum test chamber 4 via a vacuum angle valve 7 and mainly includes a turbomolecular pump 8 and a mechanical pump 9; and the exhaust gas processor 12 is connected to an exhaust gas discharge pipe 10 equipped with a vacuum shut-off valve 11.

[0026] The inner diameter of the deuterated diborane cylinder 1 is 200mm, 1500mm high, 40L volume, internal pressure greater than 12MPa. When the vacuum test chamber 4 is evacuated, the deuterated diborane gas cylinder 1 is in a closed state. After the test is completed, the gas cylinder is immediately closed.

[0027] The flow control range of the flow control valve 3 is 5.0×10 -6 ~ 1.25×10 3 mbar·L / s, flow rate adjustment scale value is 1.3×10 -9 mbar·L / s, working pressure range is 1.0×10 -8 mbar~2.5 bar, installed On the 6 mm exhaust pipe 2, before testing the deuterated diborane sample, the flow control valve 3 is in the closed state.

[0028] The inner diameter of the vacuum test chamber 4 The chamber is 100mm wide, 3mm thick, and 500mm long. In order to fix the chamber, a welding bracket is placed at its bottom. One end of the chamber is welded to the exhaust pipe for passing the deuterated diborane sample. Since the deuterated diborane sample is toxic and harmful to the human body once leaked, the vacuum degree of the chamber needs to be monitored in real time.

[0029] The range of the vacuum gauge 5 is 10 -8 ~10 5The quadrupole mass spectrometer 6 is connected to the test chamber using a knife-edge flange and an oxygen-free copper seal. It remains open during chamber evacuation and testing of deuterated diborane samples, and a vacuum gauge monitors changes in the chamber vacuum level in real time. The quadrupole mass spectrometer 6 is also connected to the test chamber using a knife-edge flange and an oxygen-free copper seal. To ensure its service life and test accuracy, it is turned on to test the deuterated diborane sample when the chamber vacuum level drops below 10-3 Pa.

[0030] The vacuum pumping unit passes through a CF40, with a leakage rate of < 1.3×10 -7 A Pa·L / s vacuum angle valve 7 is connected to the vacuum test chamber 4. It primarily comprises a 200 L / s turbomolecular pump 8 and a 20 L / s mechanical pump 9. During initial evacuation of the vacuum test chamber 4, only the mechanical pump 9 is activated to provide vacuum pumping capacity. Once the vacuum level within the vacuum test chamber 4 is sufficient for turbomolecular pump 8 to activate, the turbomolecular pump 8 can be directly activated to achieve a better vacuum environment.

[0031] The exhaust gas processor 12 is connected to the mechanical pump 9 via the exhaust gas discharge line 10, which includes a two-stage alkaline spray and an exhaust gas blower. The exhaust gas discharge line 10 has an inner diameter of 1 / 2 inch, a wall thickness of 3mm, and is made of stainless steel. A 12.7mm diameter, leak rate < 1.3×10 -7 Before the deuterated diborane sample is introduced into the vacuum test chamber 4, the vacuum shutoff valve 11 is in the open state, the secondary alkaline nozzle continues to spray, and the exhaust fan is in the normally open state, thereby ensuring sufficient absorption and discharge of exhaust gas during the test.

[0032] The specific working process of the boronized diborane detection system is as follows: First, open the vacuum angle valve 7, vacuum stop valve 11 and vacuum gauge 5 in the system, close the flow control valve 3, turn on the mechanical pump 9 to pump the vacuum degree of the vacuum test chamber 4 to about 10Pa, then turn on the molecular pump 8 to pump the vacuum degree of the vacuum test chamber 4 to 10 -6The deuterated diborane gas cylinder 1 is opened and the flow control valve 3 is adjusted. The deuterated diborane sample is introduced from the exhaust pipe 2. The quadrupole mass spectrometer 6 is turned on to scan the deuterated diborane sample multiple times and a stable full spectrum is displayed on the public machine. The detection results of each component of the sample at this flow rate can be obtained; the flow control valve 3 is then adjusted to control the flow rate of the sample, and the detection results of each component of the sample at different flow rates can be obtained. After the test is completed, the deuterated diborane gas cylinder 1 and the flow control valve 3 are closed. The deuterated diborane sample exhaust gas enters the exhaust processor 12 through the exhaust pipe 10. After the internal secondary alkaline spray treatment, it is discharged by the exhaust blower, and the purity test of the deuterated diborane sample is completed.

[0033] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.

Claims

1. A deuterated diborane gas purity detection system in a fusion device boronization system, characterized in that: It includes a deuterated diborane gas cylinder, a flow control valve, a vacuum test chamber, a vacuum gauge, a quadrupole mass spectrometer, a vacuum exhaust unit and an exhaust gas processor; the deuterated diborane gas cylinder is connected to the vacuum test chamber through a stainless steel exhaust pipe; the flow control valve is connected to the exhaust pipe; one end of the vacuum test chamber is connected to the flow control valve, and the other end is connected to the exhaust unit through a vacuum angle valve, and is respectively connected to the vacuum gauge and the quadrupole mass spectrometer on both sides of the vacuum test chamber; the vacuum gauge is connected to the vacuum test chamber through a CF35 flange port; the quadrupole mass spectrometer is connected to the vacuum test chamber through a CF35 flange port; the vacuum exhaust unit is connected to the vacuum test chamber through a KF40 angle valve, which includes a turbomolecular pump and an oil-free mechanical pump; the exhaust gas processor is connected to the exhaust port of the vacuum exhaust unit through a stainless steel pipe equipped with a vacuum shut-off valve.

2. The deuterated diborane gas purity detection system in the boronization system of the fusion device according to claim 1, characterized in that: The deuterated diborane gas cylinder is a stainless steel gas cylinder used for storing deuterated diborane gas source.

3. The deuterated diborane gas purity detection system in the boronization system of the fusion device according to claim 1, characterized in that: The flow control range of the flow control valve is 5.0×10 -6 ~1.25×10 3 mbar·L / s, flow rate adjustment scale value is 1.3×10 -9 mbar·L / s, working pressure range is 1.0×10 -8 mbar~2.5 bar, used for gas flow control and regulation between deuterated diborane cylinder and back-end vacuum test chamber.

4. The deuterated diborane gas purity detection system in the boronization system of a fusion device according to claim 1, characterized in that: The vacuum test chamber is a stainless steel cylinder with an inner diameter of 100 mm, 500 mm long; one end is welded to a 6 mm stainless steel gas pipe, one end has a KF40 flange, and both sides have CF35 flanges for the chamber used for deuterated diborane sample testing.

5. The deuterated diborane gas purity detection system in the boronization system of a fusion device according to claim 1, characterized in that: The vacuum gauge range is 10 -8 ~10 5 Pa, and a vacuum gauge is connected at the rear to monitor the vacuum degree changes in the vacuum test chamber in real time.

6. The deuterated diborane gas purity detection system in the boronization system of a fusion device according to claim 1, characterized in that: The working range of the quadrupole mass spectrometer is 10 -3 Below Pa, the molecular weight of hydrogenated diborane is 28 and that of deuterated diborane is 32. The purity of deuterated and hydrogenated diborane in gas samples is measured by taking advantage of the principle that the difference in their molecular weights leads to different gyration radii in the mass spectrometer.

7. The deuterated diborane gas purity detection system in the boronization system of a fusion device according to claim 1, characterized in that: The vacuum pumping unit is connected to the vacuum test chamber via a vacuum angle valve, and the leakage rate of the vacuum angle valve is less than 1.3×10 -7 Pa·L / s, the pumping speed of the turbomolecular pump is 200L / s, and the pumping speed of the mechanical pump is 20L / s, which are used to provide high vacuum for the test system.

8. The deuterated diborane gas purity detection system in the boronization system of a fusion device according to claim 1, characterized in that: The exhaust gas processor is connected to the vacuum pump unit through a stainless steel pipe with an inner diameter of 1 / 2 inch. The whole unit is in a slightly negative pressure state, and the leakage rate of the vacuum stop valve is less than 1.3×10 -7 Pa·L / s, which contains two stages of alkaline spray to neutralize the diborane gas sample. After treatment, it is discharged through the exhaust blower to treat and discharge the exhaust gas of the deuterated diborane sample after the test.

9. The deuterated diborane gas purity detection system in the boronization system of a fusion device according to claim 1, characterized in that: Flange connections use oxygen-free copper sealing rings, and pipeline connections meet vacuum airtightness requirements.

10. A method for detecting the purity of deuterated diborane, characterized in that: The system according to any one of claims 1 to 9 comprises the steps of: Start the vacuum pumping unit to pump the vacuum test chamber to ≤10 -6 Pa; Open the flow control valve to introduce deuterated diborane and maintain the chamber vacuum ≤ 10 -3 Pa; The purity of deuterated diborane was calculated by measuring the intensity ratio of the peaks with molecular weights of 28 and 32 using a quadrupole mass spectrometer; The tail gas is discharged after being neutralized by two-stage alkaline spraying.

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