A compact neutron generator based on an all-glass helicon wave ion source

Abstract

The present invention discloses a compact neutron generator based on an all-glass helicon wave ion source, which belongs to the field of accelerator neutron sources. The neutron generator includes a helicon wave ion source part, a cavity part and a target part. First, deuterium gas is introduced into the ion source chamber, and then the deuterium gas is excited by an antenna, thereby generating a helicon wave plasma. Under the constraint of a magnetic field, the potential difference between an extraction electrode and an ion source cover plate is first extracted in the form of a beam, and then accelerated by the electric field between the extraction electrode and a titanium target. Finally, the deuterium ion beam bombards the titanium target, and a deuterium-deuterium fusion reaction occurs to generate neutrons. At the same time, an arc magnet and a resistor are used to suppress the secondary electrons generated by the target, so as to prevent the secondary electrons from being reversely accelerated and entering the ion source chamber. The present invention has the advantages of low energy consumption, compact structure, high plasma density, autonomous cooling, good secondary electron suppression effect, high extraction beam intensity, and high neutron yield.

Description

Technical Field

[0001] The invention belongs to the field of accelerator neutron sources, and in particular relates to a compact neutron generator based on an all-glass helicon wave ion source. Background Art

[0002] A deuterium-deuterium neutron generator is a nuclear technology device that uses deuterium nuclear fusion reactions to produce neutrons. It produces high-energy neutrons by accelerating deuterium ions and colliding them with target materials. The technical principles of a deuterium-deuterium neutron generator mainly include three aspects: ion source technology, accelerator technology, and fusion reaction. Among them, the accelerator neutron source uses an accelerator ion source to generate ions, and uses a high-voltage electric field to accelerate and bombard the target material. After the target material is bombarded by a high-energy proton beam, a deuterium-deuterium fusion reaction will occur, releasing neutrons in the 4π direction. Compared with radioactive neutron sources that use radioactive nuclides to produce neutrons, accelerator neutron sources have the advantages of high safety, good controllability, and long service life. However, improving the beam intensity and neutron yield of neutron generators is still a difficult problem. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a compact neutron generator based on an all-glass helicon wave ion source. The device adopts an all-glass helicon wave ion source to increase the plasma density, and uses a copper-based solid deuterium self-target. At the same time, magnets and resistors are used to suppress secondary electrons, thereby ensuring that the overall device is compact, simple in structure, and convenient for parts processing, while satisfying the requirements of confining the ion beam and suppressing the secondary electrons, thereby obtaining a high-current ion beam and increasing the neutron yield.

[0004] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0005] A compact neutron generator based on an all-glass helicon wave ion source, the neutron generator comprising an ion source part, a chamber part, a target part and its supporting vacuum pumping system, a high-voltage feed system, a radio frequency system, a cooling system and a gas supply system; the ion source part, the chamber part and the target part are connected in sequence from top to bottom, wherein:

[0006] The ion source part is used to receive the gas fed by the gas supply system, and is connected to the matcher of the radio frequency system based on the antenna, and controls the radio frequency power so that the antenna excites the fed gas to generate helicon wave plasma;

[0007] The extraction part is used to introduce the plasma into the chamber part in the form of an ion beam;

[0008] The chamber part is used to create a vacuum environment for the ion beam in combination with a matching vacuum pumping system;

[0009] The target part is used to concentrate the ion beam in a vacuum environment, and generate neutrons by a deuterium-deuterium fusion reaction through a high-voltage feed system;

[0010] The cooling system provides cooling channels for the ion source part and the target part respectively.

[0011] Furthermore, the ion source part is fixed by bolting between the ion source cover plate and the upper cover plate of the chamber; the ion source chamber is a cylindrical body with an upper round cover capped, a small protruding hollow cylinder and a lower opening; the ion source chamber is fixed by bolting between the glass cover plate and the ion source cover plate; an antenna and a magnet are placed outside the ion source chamber; after the coil is connected to the radio frequency system, the gas inside the ion source chamber is excited to generate helicon wave plasma, and the magnet confines the helicon wave plasma.

[0012] Furthermore, the chamber body of the chamber part is cylindrical in shape, and the chamber upper cover and the chamber lower cover are connected by bolts. Sealing rings are used between the upper and lower covers and the chamber for vacuum sealing. An exhaust port is provided around the chamber, and a vacuum pumping system is installed at the exhaust port to provide a vacuum environment inside the chamber.

[0013] Furthermore, the target body part includes a coaxial lead-out electrode, a target, a connecting frame, a target support column, a target base, etc. The target support column is fixed to the target base by a fixing screw at the bottom edge, the connecting frame and the target support column are fixed by bolt connection, the target and the connecting frame are fixed by bolt connection, the lead-out electrode is fixed to the connecting frame by embedding, the target base is connected to the lower cover plate of the chamber by bolts, a magnet is placed inside the lead-out electrode to suppress secondary electrons, a resistor is placed at the connecting frame to also suppress secondary electrons, and a high-voltage channel is opened inside the target base for the high-voltage feeding system to feed high voltage to the target through a high-voltage feeding line.

[0014] Furthermore, the chamber of the chamber part is made of metal, the shape and size of the chamber are determined according to the target diameter and the installation environment, functional ports are opened around the chamber for exhaust, observation and measurement, and flanges are welded at both ends of the chamber.

[0015] Furthermore, the chamber upper cover is a flange with a middle opening as a whole, the diameter of the middle opening is larger than the diameter of the lead-out tube head and smaller than the outer diameter of the ion source cover, and the chamber upper cover is made of the same material as the chamber of the chamber part.

[0016] Furthermore, the ion source chamber is made of non-metallic material, with a round cover on the upper end and a protruding hollow cylinder on which a portion of the reaction gas can enter the ion source chamber, a hollow cylinder in the middle, and a disc with a portion extending outward and a partial protrusion at the bottom. The shape of the end face is changed according to the sealing method, and the upper and lower surfaces of the lower end are respectively in contact with the glass cover plate and the ion source cover plate.

[0017] Furthermore, the ion source chamber is fixed by squeezing the glass cover plate and the ion source cover plate, and the ion source is vacuum-sealed due to the squeezing and deformation of the sealing ring.

[0018] Furthermore, the antenna is a Helicon type antenna.

[0019] Furthermore, the antenna is made of materials with excellent thermal conductivity and high electrical conductivity, a cooling channel is provided inside the antenna, and the cross section of the antenna is a hollow ring.

[0020] Furthermore, the gas is deuterium gas, which is stored in a gas storage container, and the container itself has a gas pressure gauge, a needle valve, and a pressure reducing valve.

[0021] Furthermore, an air inlet pipe is provided at the upper end of the ion source chamber, and a gas controller is installed on the air inlet pipe to control the flow rate of deuterium gas released into the ion source chamber and the opening and closing of the gas path.

[0022] Furthermore, three centrally symmetrical threaded holes and L-shaped grooves are machined on the end surface of the glass cover plate, which are used to screw in the threaded pillars and fix the annular magnet and make it coaxial with the ion source chamber, and two sealing grooves are machined on the lower end surface.

[0023] Furthermore, the protruding magnet chuck is machined with a circular hole for passing through the ion source chamber, and three through holes corresponding to the three threaded holes of the glass cover are machined at the edge. A raised circular ring is machined on one end face for fixing the antenna and making the antenna and the ion source chamber coaxial, and an L-shaped groove is machined on the other end face for fixing the annular magnet and making it coaxial with the ion source chamber.

[0024] Furthermore, a circular hole is machined in the center of the planar magnet chuck for passing through the ion source chamber, three through holes are machined at the edge corresponding to the three threaded holes of the glass cover, an L-shaped groove is machined on one end surface for fixing the magnet and making it coaxial with the ion source chamber, and the other end surface is a plane.

[0025] Furthermore, the ion source cover is made of a metal material with good thermal conductivity, has a disc shape, and has a straight ion beam extraction hole in the center, which acts as a plasma electrode and forms a vacuum seal through a sealing ring between the cover and the chamber.

[0026] Furthermore, a hollow annular cooling channel is provided inside the ion source cover plate, and a protruding cylindrical internal threaded hole is welded on the upper end surface.

[0027] Furthermore, the ion source part, the threaded support, the nut, the glass cover, the bolt, the protruding magnet chuck, and the planar magnet chuck are made of PEEK material.

[0028] Furthermore, the target base and the lower cover plate of the chamber are fixed by bolt connection.

[0029] Furthermore, the target base is made of insulating material, and is generally a small concave hollow cylinder at the upper end, a large cylinder at the lower end, and a convex disc edge at the junction of the upper and lower ends. There are 12 through holes on the convex disc edge and an L-shaped circular channel inside.

[0030] Furthermore, a high-pressure feed-in channel is machined on the lower end surface of the target base, and the high-pressure channel is cylindrical as a whole and has an internal thread at the lower end.

[0031] Furthermore, the high-pressure sealing pipe as a whole is cylindrical at both ends and a regular hexagonal flat plate in the middle. The outside of the cylinder is threaded, the upper cylinder is machined with a cylindrical hole, and the lower cylinder is machined with a conical hole; the high-pressure sealing cover as a whole is a regular hexagon on the outside, a hollow internally threaded cylinder on the inside, and a circular hole on the end face; a circular through hole is provided in the middle of the conical rubber plug.

[0032] Furthermore, the target body support column is cylindrical as a whole, has a protruding edge at the lower end, and is provided with a circular through channel inside. The protruding edge has circumferentially distributed through holes, and the upper end surface has circumferentially distributed threaded holes. The target body support column is fixed to the target base by screw connections, and the lower end surface has threaded holes.

[0033] Furthermore, the high-pressure sealing tube is fastened to the target base by threads, the high-pressure wire is inserted into the high-pressure feed-in channel, the head wire of the high-pressure wire is fixed by the connection between the threaded holes on the lower end surface of the bolt target body support column, and then fixed to the target base by the radial force of the conical rubber plug and the axial force of the high-pressure sealing cover, and a sealing groove is provided on the side of the high-pressure sealing pipe that contacts the target base.

[0034] Furthermore, the upper and lower ends of the connecting frame are disc-shaped, both of which are provided with circumferentially distributed through holes, and the middle part is a rectangular parallelepiped with rounded corners and has two circular through channels inside. The connecting frame is fixed to the target support column by screw connection.

[0035] Furthermore, the lower shielding cover as a whole is an L-shaped cylinder with a through opening at the lower end and an inwardly extending upper end, and the upper end is provided with circumferentially distributed through holes, and the lower shielding cover is fixed to the lower end of the connecting frame by bolts; the upper shielding cover as a whole is a through opening at the lower end, and the upper end extends outward with an L-shaped outer edge, and the upper end is provided with circumferentially distributed through holes, and the upper shielding cover is fixed to the upper end of the connecting frame by bolts.

[0036] Furthermore, the resistance element is fixed by bolts between the upper and lower ends of the connecting frame.

[0037] Furthermore, the target is based on oxygen-free copper and has a coating on the surface, wherein the coating is a titanium film, and the coating area and thickness are set according to ion beam and neutron parameters.

[0038] Furthermore, the target and the connecting frame are fixed by bolt connection.

[0039] Furthermore, the high-voltage sealing cover and the high-voltage sealing tube are made of insulating material and are used to press the high-voltage feed line onto the target support.

[0040] Furthermore, the lead-out electrode is divided into two parts, the lead-out electrode head and the lead-out electrode straight tube, the two parts are matched and fixed by a slot, the lead-out electrode head is provided with a circular hole, and an inner concave ring is provided inside the upper end of the lead-out electrode straight tube.

[0041] Furthermore, the magnet bracket is fixed by being placed on the concave circular ring inside the lead-out electrode straight cylinder, and the magnet bracket is provided with two symmetrical square holes.

[0042] Furthermore, the magnet box is a rectangular parallelepiped with a hollow interior and no cover on the upper part, and the upper part has a protruding frame, and the magnet box cover is a rectangular parallelepiped with no upper cover plate and a hollow interior.

[0043] Furthermore, the lead-out electrode straight tube is fixedly matched with the target support column through a slot.

[0044] Furthermore, the annular magnet is made of NdFeB or SmCo, the core provides a 1.1T magnetic field, and the upper and lower end surfaces are magnetized surfaces; the rectangular magnet is made of NdFeB or SmCo, the core provides a 1.1T magnetic field, and the two largest rectangular surfaces are magnetized surfaces.

[0045] Furthermore, the target body part, the target body support column, the connecting frame, the target body, and the lead-out electrode are all made of materials with good conductive effects, and the high-voltage sealing cover and the high-voltage sealing tube are made of insulating materials.

[0046] Furthermore, a 90 kV high voltage is applied to the target support column, and the high voltage is transmitted to the target and the extraction electrode. The potential on the target and the extraction electrode is 90 kV. There is no high voltage on the ion source cover (plasma electrode), and the potential is 0. An electric field is generated between the extraction electrode, the target and the ion source cover (plasma electrode), and the ion beam is drawn into the chamber and bombards the target.

[0047] Furthermore, an inclined fluorinated liquid inlet channel and a horizontal fluorinated liquid outflow channel are opened on the side of the high-pressure channel.

[0048] Furthermore, the ion source partial cooling system includes antenna and ion source cover cooling.

[0049] Furthermore, the target body partial cooling system has target cooling, the coolant enters through the coolant inlet channel, flows out through the coolant outflow channel, flows through the target base, the target body support column, the connecting frame and the target, and the channels between the target base and the target body support column, the target body support column and the connecting frame, and the connecting frame and the target are water-sealed by sealing rings to prevent the coolant from leaking.

[0050] Furthermore, the resistivity of the coolant is greater than or equal to 4MΩ·cm, ensuring that the target surface temperature is less than 120°C and the overall temperature of the coil is less than 50°C. The coolant is pumped into the cooling part through a cooler, and the coolant pressure, flow rate and temperature are set by the cooler.

[0051] Furthermore, the sealing ring is made of fluororubber, with a circular or rectangular cross-section, and is placed in the sealing groove. After being squeezed under pressure, it fills the sealing groove to form a vacuum seal. A cooling circulation channel is set between the ion source chamber and the plasma water-cooled cover to achieve cooling of the ion source upper and lower cover plates, the ion source chamber and the coil.

[0052] The beneficial effects of the present invention are:

[0053] 1. The present invention adopts an all-glass helicon wave ion source and a copper-based solid deuterium self-target. It can not only ensure the overall device is compact, low in energy consumption, and simple in structure, but also increase the plasma density, thereby obtaining a high-current ion beam and increasing the neutron yield;

[0054] 2. The present invention adopts a combination of magnet and resistor to suppress secondary electrons, which greatly enhances the effect of suppressing secondary electrons;

[0055] 2. The present invention can draw out a beam current of 10 mA under a high voltage of 90 kV, and the neutron yield can reach more than 2E9 n / s;

[0056] 3. The present invention as a whole adopts a common sealing method, a convenient quick-insert connector, and a convenient threaded connection, which can be easily assembled and replaced with parts later, thus reducing production and use costs and facilitating commercialization. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 It is a cross-sectional schematic diagram of a compact neutron generator based on an all-glass helicon wave ion source of the present invention;

[0058] Figure 2 This is a schematic diagram of the assembly of the ion source;

[0059] Figure 3 is a partial cross-sectional view of the ion source;

[0060] Figure 4 is a schematic diagram of the antenna;

[0061] Figure 5 is a schematic diagram of the chamber;

[0062] Figure 6 It is one of the cross-sectional views of the target part;

[0063] Figure 7 This is a schematic diagram of the fixed assembly of rectangular magnets;

[0064] Figure 8 This is the second partial cross-sectional view of the target body;

[0065] Fig. 9 This is the third partial cross-sectional view of the target body;

[0066] Fig.10 It is a cross-sectional view of the connection frame, target and shielding cover;

[0067] Fig.11 This is the fourth partial cross-sectional view of the target body.

[0068] Figure numerals: 1, ion source part; 2, chamber part; 3, target part; 101, air inlet pipe; 102, flow meter; 103, quartz tube sleeve; 104, threaded support; 105, planar magnet chuck; 106, ion source chamber; 107, antenna; 108, glass cover; 109, ion source cover; 110, protruding magnet chuck; 111, annular magnet; 201, chamber upper cover; 202, chamber; 203, chamber lower cover; 204, molecular pump; 301, extraction electrode head; 302, Magnet holder; 303, rectangular magnet; 304, upper shielding cover; 305, lead-out electrode straight cylinder; 306, target; 307, resistor element; 308, connecting frame; 309, high-pressure sealing tube; 310, high-pressure sealing cover; 311, conical rubber plug; 312, target base; 313, target body support column; 314, lower shielding cover; 315, magnet box cover; 316, magnet box; 317, coolant inflow channel; 318, coolant outflow channel; 319, fluoride liquid inflow channel; 320, fluoride liquid outflow channel. DETAILED DESCRIPTION

[0069] The present invention is described in detail below in conjunction with the embodiments shown in the accompanying drawings:

[0070] like Figure 1As shown, the present invention provides a compact neutron generator based on an all-glass helicon wave ion source, which is mainly divided from top to bottom into an ion source part 1, a chamber part 2, a target part 3, and its supporting vacuum system, high-voltage feeding system, radio frequency system, cooling system and gas supply system; its working principle is: first, the gas supply system introduces reaction gas into the ion source, and then the ion source ionizes the gas through the radio frequency system to generate an ion beam flow, and the ion beam is guided into the chamber by the suspended potential carried by the extraction electrode, and finally the target part accelerates and constrains the ion beam with the help of the accelerating electrode and the high voltage on the target, and then bombards the target, so that a deuterium-deuterium fusion reaction occurs and neutrons are generated.

[0071] refer to Figure 1 and Figure 5 The main body of the neutron generator is a cylindrical chamber 202, the upper and lower ends of the chamber 202 are connected by bolts to the chamber upper cover 201 and the chamber lower cover 203, and a sealing ring is used for vacuum sealing. The chamber 202 is provided with an air extraction port, which is sealed with a copper ring and connected to the molecular pump 204 by bolts.

[0072] See also Figure 1 , Figure 2 and Figure 3 , Figure 4 The upper end of the ion source chamber 106 is capped with a round cover and a hollow cylinder protruding from it, on which a hollow cylinder is placed so that the reaction gas can enter the ion source chamber 106 from here, the middle part is a hollow cylinder, the lower end is a disc that extends outward and has a part of protrusion at the bottom, and the end face shape is changed according to the sealing method. The gas is fed in by the gas supply system through the air inlet pipe 101, and the air inlet pipe 101 is connected to a flow meter 102, and the air intake amount is controlled by the flow meter 102. The air inlet pipe 101 and the ion source chamber 106 are connected through a quartz tube sleeve 103. The two sides of the protruding disc at the lower end of the ion source chamber 106 are squeezed by the glass cover plate 108 and the ion source cover plate 109, and the squeezing force comes from the bolt connection between the fixed glass cover plate 108 and the ion source cover plate 109, and the glass cover plate 108 and the ion source cover plate 109 are sealed with a sealing ring at the contact between the ion source chamber 106. One of the annular magnets 111 is placed in the groove on the upper end surface of the glass cover plate 108, and is fixed on the upper side by a protruding magnet chuck 110 and a threaded support 104 and a matching nut. The other annular magnet is fixed by a threaded support 104, a protruding magnet chuck 110 and a planar magnet chuck 105 and a matching nut. The antenna 107 is fixed by two protruding magnet chucks, and the cooling liquid inlet and outlet of the antenna 107 are equipped with a quartz tube sleeve 103 for inserting a water pipe and passing the cooling liquid. An annular cooling liquid channel is formed inside the ion source cover plate 109, and a protruding internal threaded ring is welded on the upper end surface, on which a quick-connect plug is assembled for inserting a water pipe and passing the cooling liquid.

[0073] See also Figure 1, Figure 6 , Figure 7 , Figure 8 , Fig. 9 , Fig.10 and Fig.11 The target body part 3 is composed of a target base 312, a target support column 313, a connecting frame 308, a target 306, an extraction electrode, etc. The extraction electrode is divided into two parts, the upper part is the extraction electrode head 301, and the lower part is the extraction electrode cylinder 305, and the two parts are clamped and fixed by a slot. The extraction electrode and the target support column 313 are fixed by clamping the slot. The rectangular magnet 303 is fixed to the extraction electrode cylinder 305 through the magnet holder 302, and the magnet holder 302 is fixed by contacting the convex circular ring inside the extraction electrode cylinder 305. The rectangular magnet 303 is placed in the magnet box 316, and then covered with the magnet box cover 315, and the magnet box 316 is fixed by contacting the edge of the rectangular hole of the magnet holder 302 with its convex edge. The connecting frame 308 is fixed to the target support column 313 through the through hole at the bottom edge thereof by bolt connection, and the target 306 is fixed to the connecting frame 308 through the through hole at the edge thereof by bolt connection. The upper shielding cover 304 is fixed by fixing bolts with the connecting frame 308 and the target 306, the lower shielding cover 314 is fixed by fixing bolts with the connecting frame 308 and the target support column 313, and the resistor element 307 is fixed by fixing bolts with the connecting frame 308, the target 306 and the target support column 313. The target support column 313 is fixed to the target base 312 through the through hole at the gas edge by screw connection. The target base 312 and the lower cover plate 203 of the chamber are fixed by bolt connection. The high-pressure sealing tube 309 is screwed into the target base 312 through its external thread and fixed in a threaded connection manner. The high-pressure wire is inserted into the high-pressure sealing cover 310 and the conical rubber plug 311. The head of the high-pressure wire is fixed to the target support column 313 by bolt connection. The high-pressure sealing cover 310 is screwed on the high-pressure sealing tube 309, so that the high-pressure wire is fixed to the target base 312 by the radial force of the conical rubber plug 311 and the axial force of the high-pressure sealing cover 310. A stepped channel is formed inside the target base 312, and an inclined fluoride liquid inflow channel 319 and a horizontal fluoride liquid outflow channel 320 are formed on both sides of the channel. Two L-shaped channels are formed inside the target base 312, which together with the internal channels between the target support column 313, the connecting frame 308 and the target 306 constitute a coolant inlet channel 317 and a coolant outlet channel 318. The contact surfaces between the target base 312, the target support column 313, the connecting frame 308 and the target 306 are sealed with sealing rings to prevent coolant leakage.

[0074] Preferably, the chamber 202 is made of metal with certain strength and good processing performance such as SUS304 / SUS316 / aluminum, and the chamber 202 can withstand pressure changes and has a small leakage rate. The chamber 202 is provided with a suction port, an observation port, and a measurement port as required. The functional ports provided on the chamber 202 and the flange specifications at both ends refer to GB / T 6070-2007 and GB / T 6071-2003. The diameter of the chamber 202 can be changed according to the target diameter and the installation environment. In this example, the diameter is 250 mm and the length is 472 mm.

[0075] Preferably, the vacuum system is composed of a molecular pump 204 and a chamber 202 , and the air in the chamber 202 is pumped out by the molecular pump 204 , thereby achieving a vacuum environment.

[0076] Preferably, the chamber upper cover plate 201 is made of the same material as the chamber 202, and is a flange with a central opening, and the flange specifications refer to GB / T 6070-2007. The diameter of the central through hole should be much larger than the diameter of the extraction electrode head 301 and smaller than the outer diameter of the ion source cover plate 109, which is 250 mm in this example.

[0077] Preferably, the ion source chamber 106 is made of non-metallic materials, such as quartz glass and boron nitride. The inner diameter of the ion source chamber 106 is 40 mm, and the wall thickness should not be too thick under the conditions of meeting the pressure bearing and sealing properties. In this example, the wall thickness is 5 mm.

[0078] Preferably, the cross-sectional outer diameter of the antenna 107 is 6 mm and the inner diameter is 3 mm, and the antenna 107 is a helicon type. The antenna diameter and height affect the electron density of the excited plasma, and can be adjusted according to the required ion beam performance and the diameter of the chamber 202. The antenna 107 should be made of a material with excellent thermal conductivity and high electrical conductivity, and in this example, the material is copper.

[0079] Preferably, the radio frequency system is connected to the antenna 107 via a matcher, and the radio frequency power is adjusted via a radio frequency power supply.

[0080] Preferably, in the gas supply system, the gas introduced into the gas inlet pipe 101 is deuterium gas, which is stored in a gas storage bottle and flows into the ion source chamber 106 through the gas inlet pipe 101 .

[0081] Preferably, the flow meter 102 is installed on the air inlet pipe 101 to control the flow rate of the hydrogen isotope gas released into the ion source chamber 106 , and the flow rate in this example is 15 SCCM.

[0082] Preferably, the upper end surface of the glass cover plate 108 is machined with three centrally symmetrical threaded holes and an L-shaped groove, which are used to screw in the threaded support 104 and fix the annular magnet 111 and make it coaxial with the ion source chamber 106, and the lower end surface is machined with two sealing grooves for sealing the vacuum.

[0083] Preferably, the protruding magnet chuck 110 is machined with a circular hole for passing through the ion source chamber 106, and three through holes corresponding to the three threaded holes of the glass cover 108 are machined at the edge. One end face has a raised circular ring for fixing the antenna 107 and making the antenna 107 and the ion source chamber 106 coaxial, and the other end face has an L-shaped groove for fixing the annular magnet 111 and making it coaxial with the ion source chamber 106.

[0084] Preferably, a circular hole is machined in the center of the planar magnet chuck 105 for passing the ion source chamber 106, three through holes are machined at the edge corresponding to the three threaded holes of the glass cover 108, an L-shaped groove is machined on one end face for fixing the annular magnet 111 and making it coaxial with the ion source chamber 106, and the other end face is a plane.

[0085] Preferably, the ion source cover plate 109 is made of 304 stainless steel material and has a disc shape. A straight ion beam extraction hole with a diameter of 6 mm is opened in the center, which acts as a plasma electrode. A vacuum seal is formed by sealing with the sealing ring between the chamber upper cover plate 201. A hollow annular cooling channel is provided inside the ion source cover plate 109. The cross-section of the cooling channel is a rectangle of 8 mm×15 mm, and a protruding cylindrical internal threaded hole is welded on the upper end face.

[0086] Preferably, the ion source part 1, the threaded support 104, the nut, the glass cover 108, the bolt, the protruding magnet chuck 110, and the planar magnet chuck 105 are made of PEEK material.

[0087] Preferably, the target base 312 is made of polyformaldehyde material, and is generally a small concave hollow cylinder at the upper end, a large cylinder at the lower end, and a convex disc edge at the junction of the upper and lower ends. The convex disc edge has 12 through holes and an L-shaped circular channel is provided inside.

[0088] Preferably, a high-pressure feed-in channel is machined on the lower end surface of the target base 312, and the high-pressure channel is cylindrical as a whole and has an internal thread at the lower end.

[0089] Preferably, the high-pressure sealing tube 309 is a whole with cylinders at both ends and a regular hexagonal flat plate in the middle, the outside of the cylinder is threaded, the upper cylinder is machined with a cylindrical hole, and the lower cylinder is machined with a conical hole; the high-pressure sealing cover 310 is a whole with a regular hexagonal outside and a hollow internally threaded cylinder inside, and a circular hole is machined on the end face; the conical rubber plug 311 is provided with a circular through hole in the middle, with a diameter of 8.8 mm.

[0090] Preferably, the target support column 313 is cylindrical as a whole, has a protruding edge at the lower end, and is provided with a circular through channel inside. The protruding edge has circumferentially distributed through holes, and the upper end surface has circumferentially distributed threaded holes. The target support column 313 is fixed to the target base 312 by screw connection, and the lower end surface has threaded holes.

[0091] Preferably, the high-pressure sealing tube 309 is fastened to the target base 312 by threads, the high-pressure wire is inserted into the high-pressure feed-in channel, the head wire of the high-pressure wire is fixed by the connection between the threaded holes on the lower end surface of the bolt target body support column 313, and then fixed to the target base 312 by means of the radial force of the conical rubber plug 311 and the axial force of the high-pressure sealing cover 310, and a sealing groove is provided on the side of the high-pressure sealing pipe that contacts the target base 312.

[0092] Preferably, the upper and lower ends of the connecting frame 308 are disc-shaped, both of which are provided with circumferentially distributed through holes, and the middle part is a rectangular parallelepiped with rounded corners and has two circular through-channels inside. The connecting frame 308 is fixed to the target support column 313 by screw connection.

[0093] Preferably, the lower shielding cover 314 is an L-shaped cylinder with a lower opening and an upper end extending inward, and the upper end is provided with circumferentially distributed through holes. The lower shielding cover 314 is fixed to the lower end of the connecting frame 308 by bolts; the upper shielding cover 304 is an L-shaped cylinder with a lower opening and an L-shaped outer edge extending outward at the upper end, and the upper end is provided with circumferentially distributed through holes. The upper shielding cover 304 is fixed to the upper end of the connecting frame 308 by bolts.

[0094] Preferably, the resistance element 307 is fixed by bolts between the upper and lower ends of the connecting frame 308. The resistance element 307 is a resistor with a resistance value of 601 kΩ, and the number is 12.

[0095] Preferably, the target 306 is based on oxygen-free copper and is coated on the surface. The coating is a titanium film with a coating diameter of 58 mm and a coating thickness of 10 um.

[0096] Preferably, the high-pressure sealing cover 310 and the high-pressure sealing tube 309 are made of peek material, and are used to press the high-pressure feed line onto the target support.

[0097] Preferably, the lead-out electrode is divided into two parts, the lead-out electrode head 301 and the lead-out electrode straight tube 305, the two parts are matched and fixed by a slot, the lead-out electrode head 301 is machined with a circular hole with a diameter of 12 mm, and the upper end of the lead-out electrode straight tube 305 is provided with an inner concave ring.

[0098] Preferably, the magnet support 302 is fixed by being placed on the concave ring inside the lead-out electrode cylinder 305, and the magnet support 302 has two symmetrical square holes.

[0099] Preferably, the magnet box 316 is a rectangular parallelepiped with a hollow interior and no cover on the upper part, and the upper part has a protruding frame, and the magnet box cover 315 is a rectangular parallelepiped with no upper cover and a hollow interior.

[0100] Preferably, the annular magnet 111 is made of neodymium iron boron or samarium cobalt, the core provides a 1.1T magnetic field, the upper and lower end surfaces are magnetized surfaces, and the magnetic field at the center of the ion source chamber 106 is 400Gs; the rectangular magnet 303 is made of neodymium iron boron or samarium cobalt, the core provides a 1.1T magnetic field, the two largest rectangular surfaces are magnetized surfaces, and the magnetic field at the center of the lead-out electrode straight cylinder 305 is 30Gs.

[0101] Preferably, the target body part 3, the target body support column 313, the connecting frame 308, the target 306, and the lead-out electrode are all made of 304 stainless steel.

[0102] Preferably, the target support column 313 is connected to a 90 kV high voltage, which is further transmitted to the target 306 and the extraction electrode. The potential on the target 306 and the extraction electrode is 90 kV. The ion source cover 109 (plasma electrode) is not connected to a high voltage, and the potential is 0. An electric field is generated between the extraction electrode and the target 306 and the ion source cover 109 (plasma electrode), and the ion beam is drawn into the chamber and bombards the target.

[0103] Preferably, an inclined fluoride liquid inlet channel 319 and a horizontal fluoride liquid outflow channel 320 are opened on the side of the high-pressure channel, and the high-voltage line is immersed in the flowing fluoride liquid to achieve high-voltage arc extinguishing to prevent sparks. In this example, the cooling liquid speed at the inlet of the fluoride liquid channel is 15L / min.

[0104] Preferably, the cooling system of the ion source part 1 includes cooling of the antenna 107 and the ion source cover 109. In this example, the cooling liquid velocity at the inlet of the cooling liquid channel is 15 L / min.

[0105] Preferably, the target body partial cooling system has target cooling, the coolant enters through the coolant inlet channel 317, flows out through the coolant outflow channel 318, flows through the target base 312, the target body support column 313, the connecting frame 308 and the target 306, the channels between the target base 312 and the target body support column 313, the target body support column 313 and the connecting frame 308, and the connecting frame 308 and the target 306 are water-sealed by sealing rings to prevent the coolant from leaking. In this example, the coolant speed at the inlet of the coolant channel is 15L / min.

[0106] Preferably, the coolant is deionized water, and its resistivity should be greater than or equal to 16, to ensure that the surface temperature of the target 306 is less than 120° C. and the overall temperature of the antenna 107 is less than 50° C. The coolant is pumped into the cooling part by a cooler, and the coolant pressure, flow rate, and temperature can be set by the cooler.

[0107] Preferably, the sealing ring is made of fluororubber and has a circular or rectangular cross section. It is placed in the sealing groove and fills the sealing groove to form a vacuum seal after being squeezed by pressure.

[0108] In summary, the present invention sets up a helicon wave ion source based on all glass. The traditional stainless steel ion source upper cover plate and the ion source chamber 106 with double-ended through holes are eliminated, and a new ion source chamber with a through hole at one end and a gas supply system at the other end is adopted. The glass cover plate 108 made of PEEK material and the ion source cover plate 109 made of metal material are pressed against each other to fix the ion source chamber 106, eliminating the capacitance at both ends of the ion source chamber 106, making radio frequency matching easier.

[0109] The target part 3 is provided with a magnet and a resistor to achieve double suppression of secondary electrons, thereby enhancing the secondary electron suppression effect.

[0110] The ion source part 1 and the target part 3 are provided with an active cooling system.

[0111] The high-voltage channel is set up with insulation conditions. The high-voltage wire is immersed in flowing fluorinated liquid to achieve insulation conditions.

[0112] The present invention has the advantages of low energy consumption, compact structure, high plasma density, good secondary electron suppression effect, high beam intensity, high neutron yield, etc. At the same time, the whole device adopts simple thread matching and quick connectors to connect the components, which is convenient for assembly and later maintenance, and reduces production and use costs.

[0113] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. 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 compact neutron generator based on an all-glass helicon wave ion source, characterized in that: It includes an ion source part, a chamber part and a target part; the ion source part, the chamber part and the target part are connected in sequence from top to bottom; The ion source part is used to receive the fed gas, and the antenna is used to excite the fed gas to generate spiral wave plasma by controlling the radio frequency power; the ion source part is fixed by bolting between the ion source cover plate and the upper cover plate of the chamber, the ion source chamber is a cylindrical body with an upper round cover capping, a small protruding hollow cylinder and a lower opening, the ion source chamber is fixed by bolting between the glass cover plate and the ion source cover plate, and an antenna and a magnet are placed outside the ion source chamber; The chamber part is used to create a vacuum environment for the ion beam; the chamber body of the chamber part is cylindrical in shape, and the upper cover plate and the lower cover plate of the chamber are connected by bolts. The upper cover plate, the lower cover plate and the chamber body are vacuum-sealed by sealing rings, and a vacuum port is provided around the chamber body, and a vacuum pumping system is installed at the vacuum port; The target body is used to extract the plasma inside the ion source chamber and concentrate the ion beam under the vacuum environment, so as to generate a deuterium-deuterium fusion reaction to produce neutrons. The target body includes a coaxial extraction electrode, a target, a connecting frame, a target body support column and a target base. The target body support column is connected to the target base, the connecting frame is connected to the target body support column, the target is connected to the connecting frame, the extraction electrode is connected to the connecting frame, the target base is connected to the lower cover plate of the chamber, a magnet is placed inside the extraction electrode, a resistor is placed at the connecting frame, and a high-voltage channel is opened inside the target base; The gas is deuterium gas, which is stored in a gas storage container having a gas pressure gauge, a needle valve, and a pressure reducing valve; The lead-out electrode is divided into two parts, the lead-out electrode head and the lead-out electrode straight tube. The two parts are matched and fixed by a slot. The lead-out electrode head is provided with a circular hole, and the upper end of the lead-out electrode straight tube is provided with an inner concave ring. High voltage electricity is passed through the target support column, which is transmitted to the target and the extraction electrode. An electric field is generated between the extraction electrode and the target and the ion source cover electrode, which draws the ion beam into the chamber and bombards the target.

2. A compact neutron generator based on an all-glass helicon wave ion source according to claim 1, characterized in that: The upper end surface of the glass cover is machined with three centrally symmetrical threaded holes and L-shaped grooves, which are used to screw in the threaded pillars and fix the magnets and make them coaxial with the ion source chamber. The lower end surface is machined with two sealing grooves.

3. A compact neutron generator based on an all-glass helicon wave ion source according to claim 1, characterized in that: Functional ports are set around the chamber body for exhaust, observation and measurement, and flanges are welded at both ends of the chamber.

4. A compact neutron generator based on an all-glass helicon wave ion source according to claim 1, characterized in that: The upper and lower ends of the connecting frame are disc-shaped, both of which are machined with circumferentially distributed through holes. The middle part is a rectangular parallelepiped with rounded corners and has two circular through channels inside. The connecting frame is fixed to the target support column by screws.

5. A compact neutron generator based on an all-glass helicon wave ion source according to claim 1, characterized in that: The lower shielding cover is an L-shaped cylinder with a through opening at the lower end and an inwardly extending upper end, and the upper end is provided with through holes distributed circumferentially. The lower shielding cover is fixed to the lower end of the connecting frame by bolts; the upper shielding cover as a whole is a through opening at the lower end, and the upper end extends outward in an L-shaped outer edge, and the upper end is provided with through holes distributed circumferentially. The upper shielding cover is fixed to the upper end of the connecting frame by bolts.

6. A compact neutron generator based on an all-glass helicon wave ion source according to claim 1, characterized in that: An inclined fluoride liquid inlet channel and a horizontal fluoride liquid outflow channel are opened on the side of the high-pressure channel.

7. A compact neutron generator based on an all-glass helicon wave ion source according to claim 1, characterized in that: The coolant of the cooling system of the target body part enters through the coolant inlet channel, flows out through the coolant outflow channel, flows through the target base, the target body support column, the connecting frame and the target, and the channels between the target base and the target body support column, the target body support column and the connecting frame, and the connecting frame and the target are water-sealed by sealing rings to prevent the coolant from leaking out.

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