Movable D-T neutron generator for marking neutron beam nondestructive testing
阅读说明：本技术 一种用于标记中子束无损检测的移动式d-t中子发生器 (Movable D-T neutron generator for marking neutron beam nondestructive testing ) 是由 陈红涛 张凯 苏明 鲍杰 赵芳 栾广源 阮锡超 侯龙 刘世龙 龚新宝 刘邢宇 于 2020-05-26 设计创作，主要内容包括：本发明属于标记中子束无损检测技术领域,具体涉及一种用于标记中子束无损检测的移动式D-T中子发生器,包括通过加速管(6)连接的高频离子源系统(5)和真空系统及测量单元(7),设置在真空系统及测量单元(7)上的关联束靶系统(8),由高频离子源系统(5)产生并引出的D+离子束通过加速管(6)加速后轰击关联束靶系统(8)中的氚靶(68),通过D-T反应产生14MeV的中子,关联束靶系统(8)同时对中子的产生时间和位置的测量,实现对中子的出射时间和方向的标定；还包括控制高频离子源系统(5)和加速管(6)的控制系统。本发明是可适用于关联束中子照相应用的便携式D-T中子发生器。(The invention belongs to the technical field of neutron beam nondestructive testing, and particularly relates to a mobile D-T neutron generator for neutron beam nondestructive testing, which comprises a high-frequency ion source system (5), a vacuum system and a measuring unit (7) which are connected through an accelerating tube (6), and a related beam target system (8) arranged on the vacuum system and the measuring unit (7), wherein D + ion beams generated and led out by the high-frequency ion source system (5) bombard tritium targets (68) in the related beam target system (8) after being accelerated by the accelerating tube (6), and generate neutrons of 14MeV through D-T reaction, and the related beam target system (8) simultaneously measures the generation time and position of the neutrons to realize the calibration of the emission time and direction of the neutrons; the device also comprises a control system for controlling the high-frequency ion source system (5) and the accelerating tube (6). The present invention is a portable D-T neutron generator that is applicable to related beam neutron photography applications.)
1. A movable D-T neutron generator for marking neutron beam nondestructive detection is characterized in that: the device comprises a high-frequency ion source system (5), a vacuum system and a measuring unit (7) which are connected through an accelerating tube (6), and a related beam target system (8) arranged on the vacuum system and the measuring unit (7), wherein a D + ion beam generated and led out by the high-frequency ion source system (5) bombards a tritium target (68) in the related beam target system (8) after being accelerated through the accelerating tube (6), 14MeV neutrons are generated through D-T reaction, and the related beam target system (8) simultaneously measures the generation time and position of the neutrons, so that the calibration of the emission time and direction of the neutrons is realized; the vacuum system and measurement unit (7) is used for providing a vacuum environment for the associated beam target system (8); and the control system is used for controlling the high-frequency ion source system (5) and the accelerating tube (6).
2. The mobile D-T neutron generator for the non-destructive testing of labeled neutron beams of claim 1, wherein:
the high-frequency ion source system (5), the accelerating tube (6), the vacuum system and the measuring unit (7) are arranged on the high-voltage bin and the supporting structure (1), and the high-frequency ion source system further comprises a high-potential control cabinet (3) and an isolation transformer (4) which are arranged on the high-voltage bin and the supporting structure (1); the device also comprises a ground potential control cabinet (2);
the high potential control cabinet (3) is used for providing and controlling a power supply for the high frequency ion source system (5);
the isolation transformer (4) is used for providing a power supply for the high-potential control cabinet (3);
the ground potential control cabinet (2) is used for providing and controlling a power supply for the vacuum system and the measuring unit (7) and is also used for vacuum measurement and monitoring of the vacuum system and the measuring unit (7).
3. The mobile D-T neutron generator for the non-destructive testing of labeled neutron beams of claim 2, wherein:
the high-voltage bin and supporting structure (1) comprises a moving platform (12) with a plurality of rollers (17) and conical ground feet (18) arranged at the bottom, a high-voltage bin (14) arranged on the moving platform (12) is supported through a plurality of insulating supporting rods (16), and the insulating supporting rods (16) are fixedly connected with the moving platform (12) and the high-voltage bin (14) through fixing grooves (15);
the high-pressure bin (14) is a cubic box body made of stainless steel, 8 corners of the box body are of arc structures, and the sharp end is prevented from being ignited; detachable door plates are arranged on three vertical surfaces of the high-pressure bin (14), and each door plate is provided with 5 ventilation openings; the top of the high-pressure bin (14) is provided with a fan (13) for cooling equipment in the high-pressure bin (14);
the outer surface of the insulating support rod (16) is provided with a skirt edge structure;
the accelerating tube supporting rod (10) is arranged on the moving platform (12) and used for supporting the accelerating tube (6), the accelerating tube supporting rod (10) comprises a height adjusting end (11) located at the bottom end of the accelerating tube supporting rod (10) and a fixing hoop (9) located at the top end of the accelerating tube supporting rod (10), the accelerating tube supporting rod (10) is connected with the height adjusting end (11) through threads, a handle is arranged on the accelerating tube supporting rod (10), and the height of the accelerating tube supporting rod (10) can be adjusted by rotating the accelerating tube supporting rod (10) through the handle; the accelerating tube (6) is fixed by the fixing hoop (9) through an upper U-shaped clamping groove and a lower U-shaped clamping groove, and a high-strength plastic pad is adopted between the U-shaped clamping grooves and the accelerating tube (6) for pressure buffering;
when the conical anchor feet (18) are lifted, the moving platform (12) can move through the rollers (17), and when the conical anchor feet (18) fall, the moving platform (12) is fixed and supported; the height of the conical ground feet (18) is adjusted through rotation.
4. The mobile D-T neutron generator for the non-destructive testing of labeled neutron beams of claim 3, wherein:
the high-frequency ion source system (5) is arranged in the high-pressure chamber (14) and comprises a suction electrode (37) arranged at the tail end and a discharge tube (39) with the top end connected with a deuterium gas cylinder (41), a disc-shaped ion source chassis (36) is arranged at the tail end of the discharge tube (39), and the suction electrode (37) is positioned in the center of the ion source chassis (36); the high-frequency electrode (38) is sleeved on the outer surface of the discharge tube (39) and an anode probe (44) is arranged at the top end of the discharge tube (39);
the absorbing electrode (37) is positioned on the axis of the discharge tube (39) and consists of an aluminum electrode and a quartz sleeve, the aluminum electrode is a cylinder with a round hole in the center, the round hole is a beam lead-out pore channel, and the quartz sleeve is sleeved outside the aluminum electrode;
the ion source chassis (36) is made of stainless steel, one side of the ion source chassis (36) is connected with the tail end of the discharge tube (39) through a fixed pressing ring (50) and an annular gasket (49), and the fixed pressing ring (50) is connected with the ion source chassis (36) through threads; a sealing ring (48) is arranged at the tail end of the discharge tube (39), is positioned between the ion source chassis (36) and the annular gasket (49) and is used for sealing between the discharge tube (39) and the ion source chassis (36); the other side of the ion source chassis (36) is used for being connected with the accelerating tube (6);
the discharge tube (39) is made of high-purity quartz glass, the tail end of the discharge tube (39) is flat, a round hole is formed in the center of the tail end, and the round hole is used for being sleeved on the quartz sleeve of the suction electrode (37); the top end of the discharge tube (39) is provided with an air inlet hole (43), the air inlet hole (43) is connected with the deuterium gas bottle (41) through a vacuum rubber tube and is used for inputting deuterium gas into the discharge tube (39); the anode probe (44) is arranged at the center of the top end of the discharge tube (39) and used for loading an extraction voltage, and a quartz glass baffle is arranged in front of the anode probe (44) and used for preventing electrons from reversely accelerating and bombarding the anode probe (44); the anode probe (44) is made of a tungsten rod;
a needle valve (40) is further arranged between the air inlet hole (43) and the deuterium gas cylinder (41), the needle valve (40) is used for controlling the gas flow, and two ends of the needle valve (40) are respectively connected with the deuterium gas cylinder (41) and the air inlet hole (43) of the discharge tube (39) through the vacuum rubber tube; the deuterium gas cylinder (41) is fixed on a gas cylinder bracket (42) through a hoop, and the gas cylinder bracket (42) is fixedly arranged in the high-pressure bin (14);
the LED lamp further comprises a first shielding box (46) arranged on the periphery of the discharge tube (39), the top end and the tail end of the discharge tube (39) are located outside the first shielding box (46), the first shielding box (46) is made of aluminum, and a plurality of heat dissipation holes are formed in the first shielding box (46);
the high-frequency electrodes (38) are two copper rings with the same size and are separately sleeved on the outer surface of the discharge tube (39); the device also comprises a matcher (47) which is arranged inside the first shielding box (46) and is positioned below the discharge tube (39), wherein an output cable of the matcher (47) is connected with the high-frequency electrode (38), and the high-frequency electrode (38) is used for feeding power into the discharge tube (39); an N-type high-frequency shielding wire interface is arranged outside the first shielding box (46);
the ion source device is characterized by further comprising an annular permanent magnet (45) sleeved outside the discharge tube (39), wherein the permanent magnet (45) is fixedly arranged inside the first shielding box (46) through a clamping groove and is close to the tail end of the discharge tube (39) and the ion source chassis (36);
further comprising a front focusing unit (34) disposed on the ion source chassis (36) through an insulated magnetic column (33); the insulating magnetic column (33) is arranged around the position of the suction electrode (37), the front focusing unit (34) is a metal ring, and the front focusing unit (34) is connected with the insulating magnetic column (33) through threads, so that the front focusing unit (34) is insulated from the ion source chassis (36); the ion source further comprises a front focusing power supply input end (35) arranged on the ion source chassis (36), the front focusing power supply input end (35) is a power supply connector of the front focusing unit (34) and used for feeding focusing voltage, and the tail of the front focusing power supply input end is connected with the front focusing unit (34) through a lead.
5. The mobile D-T neutron generator for the nondestructive testing of labeled neutron beams as claimed in claim 4, wherein:
the accelerating tube (6) is a stainless steel straight tube and is arranged on the outer side of the high-pressure bin (14), 14 annular equalizing ring fixing pieces (54) coaxial with the accelerating tube (6) are arranged on the outer surface of the accelerating tube, each equalizing ring fixing piece (54) is provided with an equalizing ring (53) through a screw, and adjacent equalizing rings (53) are connected through equalizing resistors (52); an accelerating tube front end flange (51) is arranged at the front end of the accelerating tube (6) and used for being connected with and separated from the ion source chassis (36), so that the accelerating tube (6) is fixed on the high-pressure bin (14); the rear end of the accelerating tube (6) is provided with an accelerating tube rear end flange (55) which is used for connecting the vacuum system and the measuring unit (7);
the accelerating tube (6) is divided into 15 sections of accelerating units by 14 equalizing rings (53), wherein the first section of accelerating unit close to one end of a flange (51) at the front end of the accelerating tube is used as a rear focusing unit and is used for modulating the D + ion beams; and the rest 13 sections of the accelerating units from the rear focusing unit to a rear end flange (55) of the accelerating tube are used as voltage-equalizing accelerating sections to accelerate and focus the D + ion beams.
6. The mobile D-T neutron generator for the non-destructive testing of labeled neutron beams of claim 5, wherein:
the vacuum system and measurement unit (7) comprises a stainless steel tee pipe (59) provided with a four-way vacuum pipe (58) and a molecular pump (63), and a front end port (60) of the tee pipe (59) is in sealing connection with the accelerating tube (6) through a rear end flange (55) of the accelerating tube; the rear end port (61) of the three-way pipeline (59) is in sealing connection with the associated beam target system (8) through a bolt; the middle port (62) of the three-way pipe (59) is connected with the molecular pump (63) in a sealing mode through a flange, and the molecular pump (63) is used for vacuumizing the three-way pipe (59);
one port of the four-way vacuum pipe (58) is hermetically connected with the three-way pipeline (59) through a quick-connection flange, the remaining three ports of the four-way vacuum pipe (58) are respectively connected with a release valve (57) and two vacuum measuring pipes (56) through a quick-connection flange, and the vacuum measuring pipes (56) are full-range metal silicon pipes; the gas release valve (57) is used for releasing the internal vacuum of the three-way pipeline (59); the quick-connection flange is KF40 quick-connection flange.
7. The mobile D-T neutron generator for the non-destructive testing of labeled neutron beams of claim 6, wherein:
the associated beam target system (8) is a beam drift tube (64) provided with an associated alpha array detector (66) and an associated target tube (65);
the beam drift tube (64) is a straight tube type stainless steel tube, and a front end port (60) of the beam drift tube (64) is used for being in sealing connection with the rear end port (61) of the three-way pipeline (59); a water-cooling diaphragm (70) is arranged at a front end port (60) of the beam drift tube (64), and the beam limiting diaphragm (69) is arranged in the beam drift tube (64) and is coaxial with the beam drift tube (64); the tail end of the beam drift tube (64) is of a sealed inclined plane structure, and a tritium target (68) is arranged on the inclined plane structure; an interface (72) is arranged on the side wall of the beam drift tube (64) above the tritium target (68) and is used for connecting the associated alpha array detector (66); connecting the companion target tube (65) next to the interface (72); the D + ion beam emitted from the three-way pipeline (59) sequentially passes through the water-cooling diaphragm (70) and the beam limiting diaphragm (69) and then bombards the tritium target (68) to generate the D-T reaction and generate neutrons; the beam limiting diaphragm (69) and the water-cooling diaphragm (70) are used for limiting the beam of the D + ion beam;
the beam limiting diaphragm (69) is divided into a detachable front section and a detachable rear section, the front section is connected with the rear section through threads, and the rear section is fixed with the beam drift tube (64) through the water-cooling diaphragm (70) by bolts; the front section is disassembled according to actual requirements, so that the distance between a beam limiting hole of the beam limiting diaphragm (69) and the tritium target (68) is adjusted;
the top end of the accompanying target tube (65) is provided with a detector (71) in a column sealing mode, and the tail end of the accompanying target tube (65) is in sealing communication with the beam drift tube (64); two coaxial back scattering diaphragms (67) are arranged in the accompanying target tube (65); the distances between the two backscattering diaphragms (67) and the tritium target (68) are respectively 5cm and 25 cm; the detector (71) is used for monitoring the source intensity of the neutron source in the D-T reaction; the front end of the detector (71) is provided with a beam limiting hole;
the associated alpha array detector (66) comprises a second shielding box (73) provided with an associated beam detector joint (77) at the outer part, and a straight-tube-shaped array detector shell (74) hermetically penetrates through the bottom end of the second shielding box (73), wherein the array detector shell (74) is used as an associated beam pipeline communicated with the beam drift tube (64); a signal readout circuit (75) disposed at an upper end of the array detector housing (74) inside the second shield box (73); two multi-anode photomultiplier tubes (76) are also stacked inside the array detector shell (74); a flange (82) is arranged at the bottom end opening of the array detector shell (74), and the flange (82) is used for the sealed connection of the associated alpha array detector (66) and the interface (72) of the beam current drift tube (64); the array detector is characterized by further comprising sapphire glass (78), a scintillator detector (79), an aluminum foil (80) and a light-proof pressure ring (81) which are sequentially arranged between the array detector shell (74) and the flange (82), wherein the light-proof pressure ring (81) and the aluminum foil (80) are fixed on the scintillator detector (79) through the flange (82), the scintillator detector (79) is optically coupled with the sapphire glass (78) through silicone grease, and the sapphire glass (78) is fixed on the multi-anode photomultiplier (76) through silicone grease; the signal reading circuit (75) is connected with the multi-anode photomultiplier (76) through a socket and is used for reading signals;
the axes of the beam drift tube (64), the accompanying target tube (65) and the associated beam pipeline intersect at the center of the tritium target (68); the associated beam duct is at a 90 DEG angle to the centerline of the beam drift tube (64); the angle between the inclined plane structure and the beam drift tube (64) is 45 degrees; the companion target tube (65) and the associated alpha array detector (66) are located on the same side of the beam drift tube (64);
the target holder of the tritium target (68) is designed to be a concave groove, and an insulating rubber ring is arranged at the inner edge of the target holder and can be used for mounting the solid tritium target; an insulator film is arranged on the inner wall of the target holder to insulate the tritium target (68) from the target holder; the upper end of the target holder is provided with a gas pipe fixing groove for fixing a cooling gas pipe, the outlet of the cooling gas pipe is aligned to the center of the tritium target (68), and the tritium target (68) is cooled in a gas cooling mode under the condition that the D + ion beam is less than 100 mu A; and a water cover installation groove is arranged around the target holder, and the tritium target (68) is cooled in a water cooling mode under the condition that the D + ion beam is more than 100 mu A.
8. The mobile D-T neutron generator for the non-destructive testing of labeled neutron beams of claim 7, wherein:
the high-potential control cabinet (3) is arranged in the high-voltage cabin (14), and a radio frequency power supply (25), a rear focusing power supply (26), an anode power supply (27), a power supply controller (28), a front focusing power supply (29) and a high-potential control unit (30) are arranged in the high-potential control cabinet;
the radio frequency power supply (25) is connected with the matcher (47) through a high-frequency feed-in line and is used for generating a high-frequency electric field in the discharge tube (39); the output power supply of the rear focusing power supply (26) is connected with the rear focusing unit and is used for controlling the rear focusing unit;
the output voltage of the anode power supply (27) is connected with the anode probe (44) and is used for providing positive voltage for the extraction of the D + ion beam;
the power supply controller (28) is powered by a 220V power supply output end (31) of the isolation transformer (4) and is used for providing power supply control for the radio frequency power supply (25), the rear focusing power supply (26), the suction electrode power supply (27), the front focusing power supply (29), the high potential control unit (30) and the fan (13); the isolation transformer (4) is arranged on the mobile platform (12) below the outside of the high-voltage cabin (14);
the output end of the front focusing power supply (29) is connected with the input end (35) of the front focusing power supply to provide a beam bunching voltage for the front focusing unit (34);
the high potential control unit (30) is used for converting an optical signal into a second electric signal, the second electric signal is used for controlling the starting and stopping of the power supply controller (28), and is also used for controlling the output of the radio frequency power supply (25), the rear focusing power supply (26), the suction electrode power supply (27) and the front focusing power supply (29).
9. The mobile D-T neutron generator for the non-destructive testing of labeled neutron beams of claim 8, wherein:
a molecular pump controller (19), a ground potential control unit (20), a main power supply controller (21), a high-voltage power supply (22), a vacuum measuring instrument (23) and a mechanical pump (24) are arranged in the ground potential control cabinet (2);
the total power supply controller (21) is used for controlling the power supply of the whole neutron generator system;
the output end of the high-voltage power supply (22) is connected with the high-voltage cabin (14) through a high-voltage feed-in line to provide high voltage for the acceleration of the D + ion beam; the vacuum measuring instrument (23) is connected with the vacuum measuring tube (56) and is used for vacuum measurement and monitoring in the three-way pipeline (59); the vacuum value measured by the vacuum measuring instrument (23) is fed back to the control system and is used for controlling the starting and the closing of the molecular pump (63);
the mechanical pump (24) is used as a pre-pump and is connected with the molecular pump (63) through a corrugated pipe; the molecular pump controller (19) is connected with the molecular pump (63) through a control line and is used for controlling the starting and stopping of the molecular pump (63);
the ground potential control unit (20) is connected with the high potential control unit (30) through an optical fiber, the ground potential control unit (20) converts a first electric signal serving as a control command into the optical signal and transmits the optical signal to the high potential control unit (30) through the optical fiber, and the high potential control unit (30) converts the optical signal into a second electric signal to control equipment of the high potential control cabinet (3).
10. The mobile D-T neutron generator for the non-destructive testing of labeled neutron beams of claim 9, wherein:
the control system comprises control software and a control module, and the control software is arranged in the ground potential control unit (20); the control module comprises a PLC module and a first photoelectric isolation module which are arranged in the ground potential control unit (20), and a second photoelectric isolation module which is arranged in the high potential control unit (30);
the control software controls the first photoelectric isolation module to convert the first electric signal into the optical signal through the PLC module, the optical signal is transmitted to the second photoelectric isolation module through the optical fiber, the second photoelectric isolation module converts the optical signal into the second electric signal, the second electric signal is transmitted to the power supply controller (28), and the power supply controller (28) is connected with the suction power supply (27), the radio frequency power supply (25), the front focusing power supply (29) and the rear focusing power supply (26).
Technical Field
The invention belongs to the technical field of marked neutron beam nondestructive testing, and particularly relates to a movable D-T neutron generator for marked neutron beam nondestructive testing.
Background
The fast neutron generator is an accelerator neutron source which generates monoenergetic neutrons by using fusion reaction of deuterium and tritium (D-D) and utilizes low-energy D + ion beams (energy is less than 400keV) to bombard a deuterium titanium target (DTi) or a tritium Titanium Target (TTi) to respectively generate 2.5MeV or 14MeV monoenergetic neutrons, and can be widely applied to the fields of nuclear data measurement, reactor material shielding experiments, neutron detector scales, fast neutron nondestructive detection and the like.
at present, neutron generators are mainly classified into three types, one type is that a high-voltage multiplier is utilized to accelerate D + ions of several mA to dozens of mA to 300-400keV and then bombard a water-cooled target, and the yield of D-D reaction fast neutrons can reach 0.1-5 × 1010the fast neutron of n/s, D-T reaction can reach 0.1-5 × 1012n/s. The neutron generator has the advantages of large volume, more bunching units, complex accessory equipment and complex operation, and is mainly applied to larger departmentsAnd the laboratory is commonly used for nuclear data measurement, reactor material shielding experiment, neutron activation analysis and the like. The type of the neutron generator has large volume and is not suitable for being used in the environment with small field. In addition, the target spot is larger under high beam current, so that the application of the associated beam neutron detection experiment is not facilitated. The second type is a small sealed neutron tube, which works by accelerating a small beam of D + ion beam to about 100keV, bombarding a deuterium-titanium target (DTi) or a tritium-Titanium Target (TTi) to generate neutrons, and the D-D reaction neutron yield of the neutron tube is generally more than 107The neutron yield of n/s, D-T reaction is generally not more than 109the third type is a compact neutron source with the volume between a high-voltage multiplier and a sealed neutron tube, the neutron source utilizes an external vacuum pump to realize dynamic vacuum in a system, can disassemble a target material, can realize the replacement of the target material and improve the service life, but the target is at a high potential and must be cooled by liquid with high resistivity, Chinese patent (CN105407621A) mentions that pure water is cooled by 20k omega of resistivity, but the water purification equipment is complex, the flow rate is slow, the improvement of the cooling effect is limited, the target is at the high potential, and an associated alpha detector is arranged near the target piece, so that ignition and high-voltage discharge interference are easily caused, and the application of associated beam nondestructive neutron detection is not realized.
Disclosure of Invention
The invention aims to provide a D-T mobile neutron generator which can overcome the defects of the prior art and is suitable for associated beam fast neutron nondestructive testing.
In order to achieve the above purpose, the technical scheme adopted by the invention is a mobile D-T neutron generator for marking neutron beam nondestructive testing, which comprises a high-frequency ion source system, a vacuum system and a measuring unit which are connected through an accelerating tube, and a related beam target system arranged on the vacuum system and the measuring unit, wherein a D + ion beam generated and led out by the high-frequency ion source system bombards a tritium target in the related beam target system after being accelerated by the accelerating tube, 14MeV neutrons are generated through D-T reaction, and the related beam target system simultaneously measures the generation time and position of the neutrons to realize the calibration of the emission time and direction of the neutrons; the vacuum system and the measuring unit are used for providing a vacuum environment for the associated beam target system; the high-frequency ion source system and the control system of the accelerating tube are controlled.
Further, in the present invention,
the high-frequency ion source system, the accelerating tube, the vacuum system and the measuring unit are arranged on a high-voltage cabin and a supporting structure, and the high-frequency ion source system further comprises a high-potential control cabinet and an isolation transformer which are arranged on the high-voltage cabin and the supporting structure; the device also comprises a ground potential control cabinet;
the high potential control cabinet is used for providing and controlling a power supply for the high frequency ion source system;
the isolation transformer is used for providing a power supply for the high-potential control cabinet;
the ground potential control cabinet is used for providing and controlling power supplies for the vacuum system and the measuring unit and is also used for vacuum measurement and monitoring of the vacuum system and the measuring unit.
Further, in the present invention,
the high-voltage bin and supporting structure comprises a moving platform, the bottom of the moving platform is provided with a plurality of rollers and conical ground feet, the high-voltage bin arranged on the moving platform is supported by a plurality of insulating supporting rods, and the insulating supporting rods are fixedly connected with the moving platform and the high-voltage bin through fixing grooves;
the high-pressure bin is a cubic box body made of stainless steel, 8 corners of the box body are of arc structures, and the sharp end is prevented from being ignited; detachable door plates are arranged on three vertical surfaces of the high-pressure cabin, and each door plate is provided with 5 ventilation openings; the top of the high-pressure cabin is provided with a fan for cooling equipment in the high-pressure cabin;
the outer surface of the insulating support rod is provided with a skirt structure;
the accelerating tube supporting rod is arranged on the moving platform and used for supporting the accelerating tube, the accelerating tube supporting rod comprises a height adjusting end positioned at the bottom end of the accelerating tube supporting rod and a fixing hoop positioned at the top end of the accelerating tube supporting rod, the accelerating tube supporting rod is connected with the height adjusting end through threads, a handle is arranged on the accelerating tube supporting rod, and the height of the accelerating tube supporting rod can be adjusted by rotating the accelerating tube supporting rod through the handle; the accelerating tube is fixed by the fixing hoop through an upper U-shaped clamping groove and a lower U-shaped clamping groove, and a high-strength plastic pad is adopted between the U-shaped clamping grooves and the accelerating tube for pressure buffering;
when the conical ground feet are lifted up, the moving platform can move through the rollers, and when the conical ground feet are fallen down, the moving platform is fixed and supported; the height of the conical ground feet is adjusted through rotation.
Further, in the present invention,
the high-frequency ion source system is arranged in the high-voltage bin and comprises a discharge tube, the tail end of the discharge tube is provided with a suction electrode, the top end of the discharge tube is connected with a deuterium gas cylinder, the tail end of the discharge tube is provided with a disc-shaped ion source chassis, and the suction electrode is positioned in the center of the ion source chassis; the high-frequency probe is sleeved on the outer surface of the discharge tube;
the absorbing electrode is positioned on the axis of the discharge tube and consists of an aluminum electrode and a quartz sleeve, the aluminum electrode is a cylinder with a round hole in the center, the round hole is a beam leading-out pore channel, and the quartz sleeve is sleeved outside the aluminum electrode;
the ion source chassis is made of stainless steel, one side of the ion source chassis is connected with the tail end of the discharge tube through a fixed compression ring and an annular gasket, and the fixed compression ring is connected with the ion source chassis through threads; a sealing ring is arranged at the tail end of the discharge tube, is positioned between the ion source chassis and the annular gasket and is used for sealing the discharge tube and the ion source chassis; the other side of the ion source chassis is used for being connected with the accelerating tube;
the discharge tube is made of high-purity quartz glass, the tail end of the discharge tube is flat, and a round hole is formed in the center of the tail end and used for being sleeved on the quartz sleeve of the suction electrode; the top end of the discharge tube is provided with an air inlet hole, and the air inlet hole is connected with the deuterium gas cylinder through a vacuum rubber tube and used for inputting deuterium gas into the discharge tube; the anode probe is arranged at the center of the top end of the discharge tube and used for loading an extraction voltage, and a quartz glass blocking piece is arranged in front of the anode probe and used for preventing electrons from reversely accelerating and bombarding the anode probe; the anode probe is made of a tungsten rod;
a needle valve is further arranged between the air inlet hole and the deuterium gas cylinder and used for controlling the gas flow, and two ends of the needle valve are respectively connected with the deuterium gas cylinder and the air inlet hole of the discharge tube through the vacuum rubber tube; the deuterium gas cylinder is fixed on a gas cylinder bracket through a hoop, and the gas cylinder bracket is fixedly arranged in the high-pressure bin;
the discharge tube is characterized by also comprising a first shielding box arranged on the periphery of the discharge tube, wherein the top end and the tail end of the discharge tube are positioned outside the first shielding box, the first shielding box is made of aluminum, and a plurality of heat dissipation holes are formed in the first shielding box;
the high-frequency electrodes are two copper rings with the same size and are separately sleeved on the outer surface of the discharge tube; the first shielding box is arranged in the discharge tube, and the first shielding box is arranged in the discharge tube and is used for shielding the discharge tube; an N-type high-frequency shielding wire interface is arranged outside the first shielding box;
the ion source device also comprises an annular permanent magnet sleeved outside the discharge tube, wherein the permanent magnet is fixedly arranged inside the first shielding box through a clamping groove and is close to the tail end of the discharge tube and the ion source chassis;
the front focusing unit is arranged on the ion source chassis through an insulating magnetic column; the insulating magnetic column is arranged around the position of the magnetic pole, the front focusing unit is a metal ring, and the front focusing unit is connected with the insulating magnetic column through threads, so that the front focusing unit is insulated from the ion source chassis; the ion source comprises an ion source chassis, and is characterized by further comprising a front focusing power supply input end arranged on the ion source chassis, wherein the front focusing power supply input end is a power supply connector of the front focusing unit and used for feeding focusing voltage, and the tail of the front focusing power supply input end is connected with the front focusing unit through a lead.
Further, in the present invention,
the accelerating tube is a stainless steel straight tube and is arranged on the outer side of the high-pressure bin, 14 annular grading ring fixing pieces coaxial with the accelerating tube are arranged on the outer surface of the accelerating tube, each grading ring fixing piece is provided with a grading ring through a screw, and adjacent grading rings are connected through a grading resistor; the front end of the accelerating tube is provided with an accelerating tube front end flange which is used for connecting and disconnecting the ion source chassis, so that the accelerating tube is fixed on the high-pressure bin; the rear end of the accelerating tube is provided with an accelerating tube rear end flange which is used for connecting the vacuum system and the measuring unit;
the accelerating tube is divided into 15 sections of accelerating units by the 14 equalizing rings, wherein the first section of accelerating unit close to one end of a flange at the front end of the accelerating tube is used as a rear focusing unit and is used for modulating the D + ion beams; and the rest 13 sections of the accelerating units from the rear focusing unit to the rear end flange of the accelerating tube are used as voltage-equalizing accelerating sections to accelerate and focus the D + ion beams.
Further, in the present invention,
the vacuum system and the measuring unit comprise a stainless steel three-way pipeline provided with a four-way vacuum pipe and a molecular pump, and the front end port of the three-way pipeline is hermetically connected with the accelerating pipe through a flange at the rear end of the accelerating pipe; the rear end port of the three-way pipeline is in sealing connection with the associated beam target system through a bolt; the middle port of the three-way pipeline is hermetically connected with the molecular pump through a flange, and the molecular pump is used for vacuumizing the three-way pipeline;
one port of the four-way vacuum tube is hermetically connected with the three-way pipeline through a quick-connection flange, the remaining three ports of the four-way vacuum tube are respectively connected with a release valve and two vacuum measuring tubes through a quick-connection flange, and the vacuum measuring tubes are full-range metal silicon tubes; the air release valve is used for releasing the internal vacuum of the three-way pipeline; the quick-connection flange is KF40 quick-connection flange.
Further, in the present invention,
the associated beam target system is provided with an associated alpha array detector and a beam drift tube along with a target tube;
the beam drift tube is a straight tube type stainless steel tube, and the front end port of the beam drift tube is used for being in sealing connection with the rear end port of the three-way pipeline; the front end port of the beam drift tube is provided with a water-cooling diaphragm, and the beam drift tube also comprises a beam limiting diaphragm which is arranged in the beam drift tube and is coaxial with the beam drift tube; the tail end of the beam drift tube is a sealed inclined plane structure, and a tritium target is arranged on the inclined plane structure; an interface is arranged on the side wall of the beam drift tube above the tritium target and is used for connecting the associated alpha array detector; connecting the companion target tube adjacent the interface; the D + ion beam emitted from the three-way pipeline sequentially passes through the water-cooling diaphragm and the beam limiting diaphragm and then bombards the tritium target to generate the D-T reaction and generate neutrons; the beam limiting diaphragm and the water-cooling diaphragm are used for limiting the beam of the D + ion beam;
the beam limiting diaphragm is divided into a detachable front section and a detachable rear section, the front section is connected with the rear section through threads, and the rear section is fixed with the beam drift tube through the water-cooling diaphragm by using bolts; disassembling the front section according to actual needs, so as to adjust the distance between a beam limiting hole of the beam limiting diaphragm and the tritium target;
the top end of the accompanying target tube is provided with a detector in a column sealing mode, and the tail end of the accompanying target tube is in sealing communication with the beam drift tube connected with the detector; two coaxial anti-scattering diaphragms are arranged in the accompanying target tube; the distances between the two backscattering diaphragms and the tritium target are respectively 5cm and 25 cm; the detector is used for monitoring the source intensity of the neutron source in the D-T reaction; the front end of the detector is provided with a beam limiting hole;
the associated alpha array detector comprises a second shielding box, a straight-tube-shaped array detector shell and an associated beam pipeline, wherein an associated beam detector joint is arranged outside the second shielding box, the straight-tube-shaped array detector shell is hermetically arranged at the bottom end of the second shielding box in a penetrating mode, and the array detector shell is used as the associated beam pipeline communicated with the beam drift tube; the signal reading circuit is arranged at the upper end of the array detector shell and is positioned in the second shielding box; two multi-anode photomultiplier tubes are also stacked in the array detector shell; a flange is arranged at an opening at the bottom end of the array detector shell and used for sealing connection between the associated alpha array detector and the interface of the beam drift tube; the array detector further comprises sapphire glass, a scintillator detector, an aluminum foil and a light-proof pressure ring which are sequentially arranged between the array detector shell and the flange, wherein the light-proof pressure ring and the aluminum foil are fixed on the scintillator detector by the flange, the scintillator detector is optically coupled with the sapphire glass through silicone grease, and the sapphire glass is fixed on the multi-anode photomultiplier through the silicone grease; the signal reading circuit is connected with the multi-anode photomultiplier through a socket and is used for reading signals;
the axes of the beam drift tube, the accompanying target tube and the associated beam pipeline are intersected at the center of the tritium target; the associated beam pipeline and the central line of the beam drift tube form an angle of 90 degrees; the inclined plane structure and the beam drift tube form an angle of 45 degrees; the adjoint target tube and the associated alpha array detector are positioned on the same side of the beam drift tube;
the target holder of the tritium target is designed to be a concave groove, and an insulating rubber ring is arranged at the inner edge of the target holder and can be used for mounting the solid tritium target; an insulator film is arranged on the inner wall of the target holder to insulate the tritium target from the target holder; the upper end of the target holder is provided with a gas pipe fixing groove for fixing a cooling gas pipe, the outlet of the cooling gas pipe is aligned to the center of the tritium target, and the tritium target is cooled in an air cooling mode under the condition that the D + ion beam is less than 100 muA; and a water cover installation groove is arranged around the target holder, and the tritium target is cooled in a water cooling mode under the condition that the D + ion beam is more than 100 mu A.
Further, in the present invention,
the high-potential control cabinet is arranged in the high-voltage cabin, and a radio frequency power supply, a rear focusing power supply, a suction electrode power supply, a power supply controller, a front focusing power supply and a high-potential control unit are arranged in the high-potential control cabinet;
the radio frequency power supply is connected with the matcher through a high-frequency feed-in wire and is used for generating a high-frequency electric field in the discharge tube;
the rear focusing power supply output power supply is connected with the rear focusing unit and used for controlling the rear focusing unit;
the output voltage of the anode power supply is connected with the anode probe and is used for providing positive voltage for leading out the D + ion beam;
the power supply controller is powered by a 220V power supply output end of the isolation transformer and is used for providing power supply control for the radio frequency power supply, the rear focusing power supply, the suction electrode power supply, the front focusing power supply, the high potential control unit and the fan; the isolation transformer is arranged on the mobile platform below the outside of the high-voltage cabin;
the output end of the front focusing power supply is connected with the input end of the front focusing power supply and provides bunching voltage for the front focusing unit;
the high potential control unit is used for converting an optical signal into a second electric signal, the second electric signal is used for controlling the starting and stopping of the power supply controller and is also used for controlling the output of the radio frequency power supply, the rear focusing power supply, the suction electrode power supply and the front focusing power supply.
Further, in the present invention,
a molecular pump controller, a ground potential control unit, a main power supply controller, a high-voltage power supply, a vacuum measuring instrument and a mechanical pump are arranged in the ground potential control cabinet;
the main power controller is used for controlling the power supply of the whole neutron generator system;
the output end of the high-voltage power supply is connected with the high-voltage cabin through a high-voltage feed-in line to provide high voltage for the acceleration of the D + ion beam;
the vacuum measuring instrument is connected with the vacuum measuring tube and is used for vacuum measurement and monitoring in the three-way pipeline; the vacuum value measured by the vacuum measuring instrument is fed back to the control system and is used for controlling the starting and the closing of the molecular pump;
the mechanical pump is used as a backing pump and is connected with the molecular pump through a corrugated pipe;
the molecular pump controller is connected with the molecular pump through a control line and is used for controlling the starting and stopping of the molecular pump;
the ground potential control unit is connected with the high potential control unit through an optical fiber, converts a first electric signal serving as a control command into the optical signal and transmits the optical signal to the high potential control unit through the optical fiber, and the high potential control unit converts the optical signal into a second electric signal to control equipment of the high potential control cabinet.
Further, in the present invention,
the control system comprises control software and a control module, and the control software is arranged in the ground potential control unit; the control module comprises a PLC module and a first photoelectric isolation module which are arranged in the ground potential control unit, and a second photoelectric isolation module which is arranged in the high potential control unit;
the control software controls the first photoelectric isolation module to convert the first electric signal into the optical signal through the PLC module, the optical signal is transmitted to the second photoelectric isolation module through the optical fiber, the second photoelectric isolation module converts the optical signal into the second electric signal, the second electric signal is transmitted to the power supply controller, and the power supply controller is connected with the suction power supply, the radio frequency power supply, the front focusing power supply and the rear focusing power supply.
The invention has the beneficial effects that:
1. the neutron generator provided by the invention is a portable D-T neutron generator which can be suitable for marked neutron beam nondestructive testing application.
2. The neutron generator provided by the invention adopts a compact design, a front focusing unit 34 is arranged on an ion source chassis 36, a first section of accelerating unit of an accelerating tube 6 is arranged as a rear focusing unit, and the two focusing units can realize beam bunching of a D + ion beam under a short light path. Under the conditions of high voltage of 120kV and beam intensity of less than 3mA, the diameter of the target spot can be less than 2 mm.
3. The neutron generator provided by the invention adopts a high-frequency ion source, and the quartz sleeve of the suction electrode 37 is integrally formed with the discharge tube 9, so that the falling risk of the suction electrode 37 is avoided, and the mounting stability and reliability are improved.
4. The high frequency ion source system 5 employs a self-shielded design (i.e., shielded by means of the first shielding box 46), which can reduce the power interference of high frequency signals to the neutron generator head region (the neutron generator head region refers to the region including the ion source chassis 36, the anode 37, the front focusing unit 34, etc.).
5. The insulating support rod 16 of the high-voltage head is made of a polyester rod material, and compared with a traditional ceramic material, the insulating support rod has better plasticity, small density and light weight, and is favorable for reducing the overall quality of the neutron generator under the condition of ensuring high-voltage insulation.
6. The correlated beam target system 8 employs a compact dual-adjoint design, with a 150 ° dihedral gold silicon surface barrier type detector (i.e., detector 71) to monitor neutron yield, and a 90 ° dihedral angle associated alpha array detector 66 to achieve neutron tagging.
7. A beam limiting diaphragm 69 is added at a position 5cm away from the tritium target 68, the beam limiting diaphragm 69 and the beam drift tube 64 adopt a close fit collimation design, and a through hole in the center of the diaphragm is located in the center of the beam drift tube 64.
8. The neutron generator provided by the invention adopts the compact dry-
Drawings
FIG. 1 is a schematic diagram of a mobile D-T neutron generator for marking neutron beam non-destructive testing according to an embodiment of the present invention;
FIG. 2 is a schematic view of a high pressure silo and a support structure 1 according to an embodiment of the present invention;
fig. 3 is a schematic diagram of the ground potential control cabinet 2 according to the embodiment of the present invention;
fig. 4 is a schematic diagram of the high-potential control cabinet 3 according to the embodiment of the present invention;
fig. 5 is a schematic diagram of an
FIG. 6 is a schematic diagram of a high frequency ion source system 5 according to an embodiment of the present invention;
FIG. 7 is an enlarged partial schematic view of area A of FIG. 6;
FIG. 8 is a schematic view of an acceleration tube 6 according to an embodiment of the present invention;
FIG. 9 is a schematic view of a vacuum system and measurement unit 7 according to an embodiment of the present invention;
FIG. 10 is a schematic view of an associated beam target system 8 according to an embodiment of the present invention;
FIG. 11 is a cross-sectional view of an associated beam target system 8 according to an embodiment of the present invention;
FIG. 12 is a cross-sectional view of an associated alpha array detector 66 according to an embodiment of the present invention;
FIG. 13 is an enlarged partial schematic view of region C of FIG. 12;
FIG. 14 is a view from the B direction of FIG. 12;
in the figure: 1-high-voltage bin and supporting structure, 2-ground potential control cabinet, 3-high potential control cabinet, 4-isolation transformer, 5-high-frequency ion source system, 6-accelerating tube, 7-vacuum system and measuring unit, 8-associated beam target system, 9-fixed hoop, 10-accelerating tube supporting rod, 11-height adjusting end, 12-moving platform, 13-fan, 14-high-voltage bin, 15-fixed groove, 16-insulating supporting rod, 17-roller, 18-conical foot margin, 19-molecular pump controller, 20-ground potential control unit, 21-total power controller, 22-high-voltage power supply, 23-vacuum measuring instrument, 24-mechanical pump, 25-radio frequency power supply, 26-rear focusing power supply, 27-a suction electrode power supply, 28-a power supply controller, 29-a front focusing power supply, 30-a high potential control unit, 31-220V power supply output end, 32-220V power supply input end, 33-an insulating magnetic column, 34-a front focusing unit, 35-a front focusing power supply input end, 36-an ion source chassis, 37-a suction electrode, 38-a high frequency electrode, 39-a discharge tube, 40-a needle valve, 41-a deuterium gas cylinder, 42-a gas cylinder bracket, 43-a gas inlet hole, 44-an anode probe, 45-a permanent magnet, 46-a first shielding box, 47-a matcher, 48-a sealing ring, 49-an annular gasket, 50-a fixed pressure ring, 51-an accelerating tube front end flange, 52-a voltage-equalizing resistor, 53-a voltage equalizing ring and 54-a voltage equalizing ring fixing piece, 55-accelerating tube rear end flange, 56-vacuum measuring tube, 57-air release valve, 58-four-way vacuum tube, 59-three-way tube, 60-front end port, 61-rear end port, 62-middle port, 63-molecular pump, 64-beam drift tube, 65-adjoint target tube, 66-associated alpha array detector, 67-back scattering diaphragm, 68-tritium target, 69-beam limiting diaphragm, 70-water cooling diaphragm, 71-detector, 72-interface, 73-second shielding box, 74-array detector shell, 75-signal reading circuit, 76-multi-anode photomultiplier, 77-associated beam detector joint, 78-sapphire glass, 79-scintillator detector, 80-aluminum foil, 81-light-shielding pressure ring, 82-flange.
Detailed Description
The invention is further described below with reference to the figures and examples.
As shown in fig. 1, the mobile D-T neutron generator for nondestructive testing of labeled neutron beam provided by the invention comprises a high-voltage cabin and supporting structure 1, a ground potential control cabinet 2, a high potential control cabinet 3, an
The high-frequency ion source system 5 is connected with the vacuum system and the measuring unit 7 through the accelerating tube 6, the associated beam target system 8 is arranged on the vacuum system and the measuring unit 7, the D + ion beam generated and led out by the high-frequency ion source system 5 is accelerated through the accelerating tube 6 and then bombards the tritium target 68 in the associated beam target system 8, and neutrons of 14MeV are generated on the tritium target 68 through D-T reaction; the associated beam target system 8 simultaneously measures the generation time and position of neutrons (namely alpha particles), so as to realize the calibration of the emission time and direction of the neutrons; the vacuum system and measurement unit 7 is used to provide a vacuum environment for the associated beam target system 8.
The high-frequency ion source system 5, the accelerating tube 6, the vacuum system and the measuring unit 7 are arranged on the high-voltage cabin and the supporting structure 1, and the high-potential control cabinet 3 and the
the high potential control cabinet 3 is used for providing and controlling a power supply for the high frequency ion source system 5;
the
the ground potential control cabinet 2 is used for providing and controlling power supply for the vacuum system and the measuring unit 7, and is also used for vacuum measurement and monitoring of the vacuum system and the measuring unit 7.
As shown in fig. 2, the high-voltage bin and supporting structure 1 includes a moving platform 12 having a plurality of rollers 17 and tapered feet 18 at the bottom, the high-voltage bin 14 disposed on the moving platform 12 is supported by a plurality of insulating supporting rods 16, and the insulating supporting rods 16 are fixedly connected with the moving platform 12 and the high-voltage bin 14 by fixing grooves 15;
the high-pressure bin 14 is a cubic box body made of stainless steel with the thickness of 3mm, and 8 corners of the box body are of arc structures, so that the sharp end is prevented from being ignited; three vertical surfaces of the high-pressure chamber 14 are provided with detachable door plates, and each door plate is provided with 5 ventilation openings; the top of the high-pressure cabin 14 is provided with a fan 13 for cooling the equipment in the high-pressure cabin 14;
the insulating support rod 16 is made of epoxy resin material, has the characteristic of good insulating property, has certain toughness compared with the traditional magnetic column, is not easy to break, and has lighter weight; the size of the insulating support rod 16 is phi 100mm multiplied by 800mm, and in order to increase the creepage distance, the outer surface is provided with a skirt edge structure;
the accelerating tube support bar 10 comprises a height adjusting end 11 positioned at the bottom end of the accelerating tube support bar 10 and a fixing hoop 9 positioned at the top end of the accelerating tube support bar 10, the accelerating tube support bar 10 is in threaded connection with the height adjusting end 11, a handle is arranged on the accelerating tube support bar 10, and the height of the accelerating tube support bar 10 can be adjusted by rotating the accelerating tube support bar 10 through the handle; the fixed hoop 9 fixes the rear end of the accelerating tube 6 through the upper U-shaped clamping groove and the lower U-shaped clamping groove, and a high-strength plastic pad is adopted between the U-shaped clamping grooves and the accelerating tube 6 for pressure buffering, so that the accelerating tube 6 is prevented from being broken due to strong torsion;
the moving platform 12 is an aluminum plate with the thickness of 5cm, has smaller mass under the condition of ensuring enough mechanical strength, and has the size of 1m multiplied by 2m multiplied by 0.05 m; when the conical anchor 18 rises, the movable platform 12 can move through the roller 17, and when the conical anchor 18 falls, the movable platform 12 is fixed and supported; the height of the conical anchor 18 is adjusted through rotation, and the conical anchor 18 is made of high-strength stainless steel.
The high-frequency ion source system 5 (shown in figure 6) is arranged in the high-voltage chamber 14 and comprises an absorbing pole 37 arranged at the tail end and a discharge tube 39 connected with a deuterium gas bottle 41 at the top end, a disc-shaped ion source chassis 36 is arranged at the tail end of the discharge tube 39, and the absorbing pole 37 is positioned in the center of the ion source chassis 36; further comprises a high-frequency electrode 38 fitted around the outer surface of the discharge tube 39 and an anode probe 44 provided at the tip of the discharge tube 39;
the anode 37 is positioned on the axis of the discharge tube 39 and consists of an aluminum electrode and a quartz sleeve, the aluminum electrode is a cylinder with a round hole in the center, the round hole is a beam lead-out pore channel, and the quartz sleeve is sleeved outside the aluminum electrode;
the ion source chassis 36 is made of stainless steel, as shown in fig. 7, one side of the ion source chassis 36 is connected with the tail end of the discharge tube 39 through a fixed press ring 50 and an annular gasket 49, and the fixed press ring 50 is connected with the ion source chassis 36 through threads; a sealing ring 48 is arranged at the tail end of the discharge tube 39, is positioned between the ion source chassis 36 and an annular gasket 49 and is used for sealing between the discharge tube 39 and the ion source chassis 36 (namely, the discharge tube 39 is arranged on the ion source chassis 36 in a column sealing mode, and the suction electrode 37 is positioned between the discharge tube 39 and the ion source chassis 36); the other side of the ion source chassis 36 is used for connecting with the accelerating tube 6;
the discharge tube 39 is made of high-purity quartz glass, the tail end of the discharge tube 39 is flat, and a round hole is formed in the center of the tail end and used for being sleeved on a quartz sleeve of the suction electrode 37; the top end of the discharge tube 39 is provided with an air inlet hole 43, the air inlet hole 43 is connected with the deuterium bottle 41 through a vacuum rubber tube and is used for inputting deuterium into the discharge tube 39; the anode probe 44 is arranged at the center of the top end of the discharge tube 39 and is used for loading an extraction voltage (namely, the extraction voltage is fed into the discharge tube 39), and a quartz glass baffle is arranged in front of the anode probe 44 and is used for preventing electrons from reversely accelerating and bombarding the anode probe 44; the anode probe 44 is made of a tungsten rod;
a needle valve 40 is also arranged between the air inlet hole 43 and the deuterium gas bottle 41, the needle valve 40 is used for controlling the gas flow, and two ends of the needle valve 40 are respectively connected with the deuterium gas bottle 41 and the air inlet hole 43 of the discharge tube 39 through vacuum rubber tubes; the deuterium gas cylinder 41 is fixed on the gas cylinder bracket 42 through a hoop, and the gas cylinder bracket 42 is fixedly arranged in the high-pressure bin 14;
the LED lamp further comprises a first shielding box 46 arranged at the periphery of the discharge tube 39, the top end and the tail end of the discharge tube 39 are positioned outside the first shielding box 46, the first shielding box 46 is made of aluminum, and a plurality of heat dissipation holes are formed in the first shielding box 46;
the high-frequency electrodes 38 are two copper rings with the same size, are separately sleeved on the outer surface of the discharge tube 39, and are spaced by 2-5cm according to the actual use condition; a matching unit 47 disposed inside the first shielding box 46 and below the discharge tube 39, wherein an output cable of the matching unit 47 is connected to the high-frequency electrode 38 by brazing, and the high-frequency electrode 38 feeds power into the discharge tube 39; an N-type high-frequency shielding wire interface is arranged outside the first shielding box 46 and is used for connecting an output cable of the radio-frequency power supply 25;
the ion source further comprises an annular permanent magnet 45 sleeved outside the discharge tube 39, wherein the permanent magnet 45 is fixedly arranged inside a first shielding box 46 through a clamping groove and is close to the tail end of the discharge tube 39 and the ion source chassis 36; the matcher 47, the permanent magnet 45, the high-frequency electrode 38 and the top end of the discharge tube 39 are all arranged in a first shielding box 46, and the first shielding box 46 is used for shielding high-frequency signals;
a front focusing unit 34 disposed on the ion source chassis 36 through an insulating magnetic column 33; the insulating magnetic column 33 is welded around the position of the magnetic pole 37, the outer part of the insulating magnetic column 33 is provided with threads, the front focusing unit 34 is a metal ring, the inner ring is provided with a thread structure, and the front focusing unit 34 is connected with the insulating magnetic column 33 through the threads, so that the front focusing unit 34 is insulated from the ion source chassis 36; the ion source further comprises a front focusing power supply input end 35 arranged on the ion source chassis 36, wherein the front focusing power supply input end 35 is a power supply connector (connected with the front focusing power supply 29) of the front focusing unit 34 and is used for feeding focusing voltage, and the tail part of the front focusing power supply input end is connected with the front focusing unit 34 through a lead.
The accelerating tube 6 (see fig. 8) is a stainless steel straight tube, and is arranged outside the high-pressure bin 14, the outer surface of the accelerating tube is provided with 14 annular equalizing ring fixing pieces 54 which are coaxial with the accelerating tube 6, each equalizing ring fixing piece 54 is provided with an equalizing ring 53 through a screw, and adjacent equalizing rings 53 are connected through equalizing resistors 52; the front end of the accelerating tube 6 is provided with an accelerating tube front end flange 51 which is used for connecting and disconnecting the ion source chassis 36, so that the accelerating tube 6 is fixed on the high-pressure bin 14; the rear end of the accelerating tube 6 is provided with an accelerating tube rear end flange 55 which is used for connecting a vacuum system and the measuring unit 7;
the accelerating tube 6 is divided into 15 sections of accelerating units by 14 equalizing rings 53, wherein a first section of accelerating unit (connected with a rear focusing power supply 26) close to one end of a flange 51 at the front end of the accelerating tube is used as a rear focusing unit and used for modulating the D + ion beam; the rest 13 sections of accelerating units from the rear focusing unit to the flange 55 at the rear end of the accelerating tube are used as voltage-sharing accelerating sections to accelerate and focus the D + ion beam; the total length of the accelerating tube 6 is 0.44 meter, and the length of each equalizing ring 53 is 24.8 mm.
As shown in fig. 9, the vacuum system and measurement unit 7 includes a tee pipe 59 made of stainless steel and provided with a four-way vacuum pipe 58 and a molecular pump 63, and a front end port 60 of the tee pipe 59 is hermetically connected with the accelerating tube 6 through an accelerating tube rear end flange 55; the rear end port 61 of the three-way pipeline 59 is in sealing connection with the associated beam target system 8 through a bolt; the middle port 62 of the three-way pipeline 59 is in sealing connection with the molecular pump 63 through a flange, and the molecular pump 63 is used for vacuumizing the three-way pipeline 59;
one port of the four-way vacuum tube 58 is hermetically connected with the three-way pipeline 59 through a quick-connection flange, the remaining three ports of the four-way vacuum tube 58 are respectively connected with the air release valve 57 and the two vacuum measuring tubes 56 through a quick-connection flange, the vacuum measuring tubes 56 are full-range metal silicon tubes, and the vacuum measuring tubes 56 and the vacuum measuring instrument 23 form a digital vacuum monitoring system; the air relief valve 57 is used for releasing the internal vacuum of the tee pipe 59; the quick-connection flange is KF40 quick-connection flange; the pumping speed of the molecular pump 63 was 300L/min.
As shown in fig. 10 and 11, the correlated beam target system 8 is a beam drift tube 64 provided with a correlated α array detector 66 and a companion target tube 65;
the beam drift tube 64 is a straight tube type stainless steel tube, and the front end port 60 of the beam drift tube 64 is used for being in sealing connection with the rear end port 61 of the three-way pipeline 59 and used for ensuring the smoothness and the vacuum maintenance of the beam pipeline; a water-cooling diaphragm 70 is arranged at the front end port 60 of the beam drift tube 64, and the beam limiting diaphragm 69 is arranged in the beam drift tube 64 and is coaxial with the beam drift tube 64; the tail end of the beam drift tube 64 is a sealed inclined plane structure, and a tritium target 68 is arranged on the inclined plane structure; an interface 72 is arranged on the side wall of the beam drift tube 64 above the tritium target 68 and used for connecting the associated alpha array detector 66; an accompanying target tube 65 is connected to the interface 72; d + ion beams emitted from the three-way pipeline 59 sequentially pass through a water-cooling diaphragm 70 and a beam limiting diaphragm 69 and then bombard a tritium target 68 to generate a D-T reaction and generate neutrons; the beam limiting diaphragm 69 and the water-cooling diaphragm 70 are used for limiting the beam of the D + ion beam;
the beam limiting diaphragm 69 is divided into a detachable front section and a detachable rear section, the front section and the rear section are connected through threads, and the rear section is fixed with the beam drift tube 64 through a water-cooling diaphragm 70 by bolts; the front section is disassembled according to actual requirements, so that the distance between a beam limiting hole of the beam limiting diaphragm 69 and the tritium target 68 is adjusted; (the front section of the beam limiting diaphragm 69 is connected with the beam drift tube 64 through tight fit.)
A detector 71 (the detector 71 is a SiC detector and serves as an accompanying detector in the invention) is arranged at the top end of the accompanying target tube 65 in a column sealing mode, and the tail end of the accompanying target tube 65 is in sealing communication with the beam drift tube 64; two coaxial back scattering diaphragms 67 are arranged in the accompanying target tube 65, the thickness is 3mm, and the aperture is 8 mm; the distances between the two back-scattering diaphragms 67 and the tritium target 68 are 5cm and 25cm respectively; the accompanying target tube 65 and the central line of the beam drift tube 64 form an angle of 30 degrees; the accompanying target tube 65 is 50cm long and 3cm in inner diameter, and is made of stainless steel; the detector 71 is used for monitoring the source intensity of a neutron source in the D-T reaction; the detector 71 adopts a gold silicon surface barrier type detector, and in order to reduce the counting rate of the detector and reduce the dead time, the front end of the detector 71 is provided with a beam limiting hole with the diameter of 1 mm;
as shown in fig. 12, the associated α array detector 66 includes a
as shown in fig. 13, the multi-anode photomultiplier tube further includes a sapphire glass 78, a scintillator detector 79, an aluminum foil 80 and a light-shielding pressure ring 81, which are sequentially disposed between the
the axes of the beam drift tube 64, the accompanying target tube 65 and the associated beam tube intersect at the center of the tritium target 68; the associated beam duct makes a 90 ° angle with the center line of the beam drift tube 64; the angle between the inclined plane structure and the beam drift tube 64 is 45 degrees, so that the detector 71 and the associated alpha array detector 66 can conveniently detect alpha particles; the companion target tube 65 and the associated alpha array detector 66 are located on the same side of the beam drift tube 64;
the target holder of the tritium target 68 adopts a concave groove design, and an insulating rubber ring is arranged at the inner edge of the target holder and can be used for mounting a solid tritium target with the diameter of 50 mm; an insulator film with the thickness of 0.1mm is arranged on the inner wall of the target holder, so that the tritium target 68 is insulated from the target holder, and the measurement of a D + ion beam reaching the tritium target 68 is facilitated; the upper end of the target holder is provided with an air pipe fixing groove for fixing a cooling air pipe, the outlet of the cooling air pipe is aligned to the center of the tritium target 68, and the tritium target 68 is cooled in an air cooling mode under the condition that the D + ion beam is less than 100 muA; a water cover installation groove is arranged around the target holder, and the tritium target 68 is cooled in a water cooling mode under the condition that the D + ion beam is larger than 100 muA.
As shown in fig. 14, the associated
The high potential control cabinet 3 (see fig. 4) is arranged in the high voltage cabin 14, and a radio frequency power supply 25, a rear focusing power supply 26, a suction electrode power supply 27, a power supply controller 28, a front focusing power supply 29 and a high potential control unit 30 are arranged in the high voltage cabin;
the radio frequency power supply 25 is connected with the matcher 47 through a high frequency feed-in line and is used for generating a high frequency electric field, namely an oscillation electric field, in the discharge tube 39; the output frequency of the radio frequency power supply 25 is 108MHz, and the output power is 0-300W;
the output power of the back focusing power supply 26 is connected with the back focusing unit and is used for controlling the back focusing unit;
the output voltage of the anode power supply 27 is connected with the anode probe 44 and is used for providing positive voltage for leading out the D + ion beam; the anode power supply 27 and the radio frequency power supply 25 jointly form an auxiliary power supply of the high-frequency ion source system 5;
the power supply controller 28 is powered by a 220V power
the output end of the front focusing power supply 29 is connected with the input end 35 of the front focusing power supply to provide a beam-bunching voltage for the front focusing unit 34;
the high-potential control unit 30 is configured to convert the optical signal into a second electrical signal, where the second electrical signal is used to control the on/off of the power supply controller 28, and is further used to control the outputs of the radio frequency power supply 25, the back focusing power supply 26, the suction electrode power supply 27, and the front focusing power supply 29.
A molecular pump controller 19, a ground potential control unit 20, a general power controller 21, a high-voltage power supply 22, a vacuum measuring instrument 23 and a mechanical pump 24 are arranged in the ground potential control cabinet 2 (see fig. 3);
the main power controller 21 is used for power supply control of the whole neutron generator system;
the output end of the high-voltage power supply 22 is connected with the high-voltage cabin 14 through a high-voltage feed-in line to provide high voltage for the acceleration of the D + ion beam; the high voltage power supply 22 is a 130kV/6.5mA box power supply;
the vacuum measuring instrument 23 is connected with the vacuum measuring tube 56 and is used for vacuum measurement and monitoring in the three-way pipeline 59; the vacuum value measured by the vacuum measuring instrument 23 is fed back to the control system for controlling the starting and the closing of the molecular pump 63;
the mechanical pump 24 is used as a backing pump and is connected with the molecular pump 63 through a corrugated pipe; the pumping speed of the mechanical pump 24 is 3L/s;
the molecular pump controller 19 is connected with the molecular pump 63 through a control line and is used for controlling the starting and stopping of the molecular pump 63;
the ground potential control unit 20 is connected to the high potential control unit 30 through an optical fiber, the ground potential control unit 20 converts the first electrical signal as a control command into an optical signal, and transmits the optical signal to the high potential control unit 30 through the optical fiber, and the high potential control unit 30 converts the optical signal into a second electrical signal to control the equipment of the high potential control cabinet 3.
The control system comprises control software and a control module, and the control software is arranged in the ground potential control unit 20; the control module comprises a PLC module and a first photoelectric isolation module which are arranged in the ground potential control unit 20, and a second photoelectric isolation module which is arranged in the high potential control unit 30;
the control software controls the first photoelectric isolation module to convert the first electric signal into an optical signal through the PLC module, the optical signal is transmitted to the second photoelectric isolation module through the optical fiber, the second photoelectric isolation module converts the optical signal into a second electric signal, the second electric signal is transmitted to the power supply controller 28, and the power supply controller 28 is connected with the suction power supply 27, the radio frequency power supply 25, the front focusing power supply 29 and the rear focusing power supply 26.
The device according to the present invention is not limited to the embodiments described in the specific embodiments, and those skilled in the art can derive other embodiments according to the technical solutions of the present invention, and also belong to the technical innovation scope of the present invention.