A kind of accelerator pole adjustable radial extraction penning ion source neutron tube structure

Abstract

The application discloses a kind of neutron tube structures of accelerating polar adjustable radial extraction penning ion source, including sleeve, the one end inside sleeve is equipped with anode cylinder, the outer embedding of the cylinder body of anode cylinder is equipped with insulator, radial extraction hole is opened in the side of anode and insulator, the outside of radial extraction hole is coaxially equipped with acceleration cylinder with insulator, copper target is equipped at the tail end of acceleration cylinder;When using, adjusting nut, lengthening or compressing corrugated expansion pipe, the distance between acceleration cylinder and discharge cavity is adjusted, then external circuit is added voltage to anode cylinder, under the joint action of electric and magnetic field, gas ionizes, generates ion, ion is extracted through radial extraction hole, at this time, acceleration cylinder applies positive high voltage, ion is accelerated and extracted, and neutron is generated by hitting copper target;The present application is more easily extracted by setting radial extraction hole and configuring corrugated expansion pipe around acceleration cylinder, improves acceleration performance, controls the area of ion beam hitting copper target, improves copper target utilization rate, and improves neutron yield.

Description

Technical Field

[0001] This invention relates to the field of neutron tube technology, specifically to a neutron tube structure for a radially extracted Penning ion source with an adjustable accelerating electrode. Background Technology

[0002] The Penning ion source is a type of ion source that generates a large number of ions within a chamber through the Penning effect. It can stably discharge under low-pressure conditions and has advantages such as simple structure and stable operation. The ion source provides a continuous supply of ions to be accelerated for neutron tube accelerators. Neutron tubes have numerous applications in oil well logging. Currently, mature neutron logging technology exists, where ions provided by the ion source are accelerated by an acceleration system to obtain high-energy particles. These particles then undergo nuclear fusion with target materials to produce a 14 MeV neutron flux. Different nuclei react with different underground materials, releasing different gamma rays, characteristic times, and energy spectra to distinguish different material layers.

[0003] Patent application number [CN202111289817.1] entitled "A Neutron Tube Structure for a Conical Penning Ion Source" provides a neutron tube structure for a conical Penning ion source, including an insulating ceramic tube. One end of the insulating ceramic tube is provided with a first permanent magnet. A first cathode is fixed inside the first permanent magnet through a first ceramic ring. The inner side of the first cathode is connected to one end of a conical anode tube. The other end of the conical anode tube is connected to a second cathode and together embedded in a second ceramic ring. The outer side of the second cathode and the second ceramic ring is connected to the inner side of the second permanent magnet. By changing the shape of the anode tube, a more compact and efficient miniature ion source can be obtained.

[0004] However, existing Penning ion source neutron tubes typically employ axial ion extraction followed by target firing. During the extraction of negative ions, the low proportion of negative deuterium ions within the source results in a low total neutron yield. On the other hand, ions are accelerated by an accelerator during extraction and undergo nuclear reactions on a copper target to produce neutrons. However, the distance between the ion source discharge cavity and the accelerator significantly affects the optical properties of the ion beam and the area of ​​the ions hitting the target, thereby reducing the intensity of the extracted ion beam and the utilization rate of the copper target, leading to insufficient neutron yield. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, the present invention aims to provide a neutron tube structure for a radially adjustable accelerating electrode Penning ion source. By setting the negative ion extraction hole in the radial direction of the anode tube and arranging a corrugated telescopic tube around the accelerating tube, negative ions are more easily extracted, accelerating performance is improved, the area of ​​the ion beam hitting the copper target is controlled, the extraction beam intensity of the extracted ions is increased, the utilization rate of the copper target in the neutron tube is improved, and thus the neutron yield is increased.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] An adjustable accelerating electrode radial extraction Penning ion source neutron tube structure includes a sleeve 5. An anode tube 4 is disposed at one end inside the sleeve 5. An insulator 11 is embedded outside the body of the anode tube 4. A first radial extraction hole 15 is opened at the middle position of the body of the anode tube 4. A second radial extraction hole 18 is opened at the same position as the first radial extraction hole 15 on the side of the insulator 11. An accelerating tube 12 is disposed coaxially with the insulator 11 outside the second radial extraction hole 18. A copper target 14 is disposed at the tail end of the accelerating tube 12.

[0008] The top of the anode cylinder 4 is sequentially provided with an upper cathode 3, an upper permanent magnet 2, and an upper washer 1; the bottom of the anode cylinder 4 is sequentially provided with a lower cathode 10, a lower permanent magnet 9, and a lower washer 8.

[0009] The acceleration cylinder 12 is placed on the support frame 17 located at the other end of the sleeve 5. The inner side of the support frame 17 is connected to one end of the corrugated expansion tube 13, and the other end of the corrugated expansion tube 13 is connected to the inner side of the flange 16.

[0010] The sleeve 5, the first radial lead-out hole 15, the second radial lead-out hole 18, the flange 16, the acceleration cylinder 12, and the copper target 14 are coaxial.

[0011] The first radial lead-out hole 15 and the second radial lead-out hole 18 have the same diameter.

[0012] The two ends of the corrugated expansion tube 13 are respectively sealed and welded to the flange 16 and the support frame 17; the tail end of the acceleration cylinder 12 is sealed and welded to the flange 16.

[0013] The acceleration cylinder 12 and the copper target 14 are fixed together by threads, and there is a gap between the head end of the acceleration cylinder 12 and the support frame 17.

[0014] The insulator 11 is made of ceramic material, and the upper washer 1 and the lower washer 8 are made of rubber material.

[0015] The corrugated expansion tube 13 is made of aluminum, the sleeve 5 and nut 7 are made of alloy, and the flange 16 and acceleration cylinder 12 are made of stainless steel.

[0016] The anode cylinder 4, the insulator 11, the upper cathode 3, the upper permanent magnet 2, the upper washer 1 arranged at the top of the anode cylinder 4, and the lower cathode 10, the lower permanent magnet 9, the lower washer 8 arranged at the bottom of the anode cylinder 4 are coaxial.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] 1. This invention improves the ionization rate of the ion source by radially extracting Penning ions from the anode cylinder, thus eliminating their rotational symmetry. Furthermore, since the negative ions generated during the discharge process within the ion source move towards the anode cylinder under the influence of the electric field, radial extraction from one side of the anode cylinder is more advantageous for extracting the negative ions.

[0019] 2. This invention adjusts the position of the nut on the screw, causing the corrugated telescopic tube welded to the flange to extend and retract radially, while simultaneously causing the accelerating cylinder welded to the flange to reciprocate. This makes the distance between the accelerating cylinder and the ion source discharge cavity adjustable, increasing the intensity of the extracted ion beam and the area of ​​the ion beam hitting the copper target, thereby improving the utilization rate of the copper target and increasing the neutron yield.

[0020] 3. In this invention, the two ends of the corrugated telescopic tube are sealed and welded to the flange and the support frame, and the acceleration cylinder is sealed and welded to the flange. This allows the invention to ensure the vacuum tightness of the neutron tube under low pressure working conditions while allowing the position of the acceleration cylinder to be adjusted at any time. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structural principle of the present invention.

[0022] Figure 2 This is a three-dimensional structural diagram of the present invention.

[0023] Figure 3 This is a structural diagram of the insulator of the present invention.

[0024] In the diagram: 1 is the upper washer, 2 is the upper permanent magnet, 3 is the upper cathode, 4 is the anode cylinder, 5 is the sleeve, 6 is the screw, 7 is the nut, 8 is the lower washer, 9 is the lower permanent magnet, 10 is the lower cathode, 11 is the insulator, 12 is the acceleration cylinder, 13 is the corrugated telescopic tube, 14 is the copper target, 15 is the first radial lead-out hole, 16 is the flange, 17 is the support frame, and 18 is the second radial lead-out hole. Detailed Implementation

[0025] The structural and working principles of the present invention will be described in detail below with reference to the accompanying drawings.

[0026] See Figure 1An adjustable accelerating electrode radial extraction Penning ion source neutron tube structure includes a sleeve 5. An anode tube 4 is disposed at one end inside the sleeve 5. An insulator 11 is embedded outside the body of the anode tube 4. A first radial extraction hole 15 is opened in the middle of the body of the anode tube 4. A second radial extraction hole 18 is opened on the side of the insulator 11 at the same position as the first radial extraction hole 15. An accelerating tube 12 is disposed on the outer side of the second radial extraction hole 18 and coaxially with the insulator 11. A copper target 14 is disposed at the tail end of the accelerating tube 12. By radially extracting Penning ions from the anode tube 4, the rotational symmetry of the ion source is eliminated, thereby improving the ionization rate of the ion source. Furthermore, since the negative ions generated during the discharge process in the ion source will move towards the anode tube 4 under the action of the electric field, radial extraction from one side of the anode tube 4 is more advantageous for extracting negative ions.

[0027] The top of the anode cylinder 4 is sequentially provided with an upper cathode 3, an upper permanent magnet 2, and an upper washer 1; the bottom of the anode cylinder 4 is sequentially provided with a lower cathode 10, a lower permanent magnet 9, and a lower washer 8.

[0028] The accelerating cylinder 12 is placed on a support frame 17 located at the other end of the sleeve 5. The inner side of the support frame 17 is connected to one end of the corrugated telescopic tube 13, and the other end of the corrugated telescopic tube 13 is connected to the inner side of the flange 16. The flange 16 is fixed to one end of the sleeve 5 by a screw 6 and a nut 7. By adjusting the position of the nut 7 on the screw 6, the corrugated telescopic tube 13 welded to the flange 16 is driven to retract radially, and at the same time, the accelerating cylinder 12 welded to the flange 16 is driven to reciprocate. This makes the distance between the accelerating cylinder 12 and the ion source discharge cavity adjustable, increases the intensity of the extracted ion beam, increases the area of ​​the ion beam hitting the copper target 14, improves the utilization rate of the copper target 14, and increases the neutron yield.

[0029] See Figure 2 The sleeve 5, the first radial lead-out hole 15, the second radial lead-out hole 18, the flange 16, the acceleration cylinder 12, and the copper target 14 are coaxial.

[0030] The first radial lead-out hole 15 and the second radial lead-out hole 18 have the same diameter.

[0031] The two ends of the corrugated telescopic tube 13 are respectively sealed and welded to the flange 16 and the support frame 17; the tail end of the acceleration cylinder 12 is sealed and welded to the flange 16, so that the position of the acceleration cylinder 12 can be adjusted at any time, while ensuring the vacuum tightness of the neutron tube under low pressure working conditions.

[0032] The acceleration cylinder 12 and the copper target 14 are fixed together by threads. There is a gap between the head end of the acceleration cylinder 12 and the support frame 17, so that the acceleration cylinder 12 can be smoothly adjusted to a suitable position.

[0033] The insulator 11 is made of ceramic material, and the upper washer 1 and the lower washer 8 are made of rubber material.

[0034] The corrugated expansion tube 13 is made of aluminum, the sleeve 5 and nut 7 are made of alloy, and the flange 16 and acceleration cylinder 12 are made of stainless steel.

[0035] The anode cylinder 4, the insulator 11, the upper cathode 3, the upper permanent magnet 2, the upper washer 1 arranged at the top of the anode cylinder 4, and the lower cathode 10, the lower permanent magnet 9, the lower washer 8 arranged at the bottom of the anode cylinder 4 are coaxial.

[0036] See Figure 3 A first radial lead-out hole 15 is provided at the middle position of the outer side of the anode cylinder 4, and a second radial lead-out hole 18 is provided at the same position as the first radial lead-out hole 15 on the side of the insulator 11. The first radial lead-out hole 15 and the second radial lead-out hole 18 are in the same position and connected to each other.

[0037] The working principle of this invention is as follows: During use, the nut 7 on the adjusting screw 6 is used to extend or compress the corrugated telescopic tube 13, which drives the accelerating cylinder 12 to "push" or "pull" and reciprocate radially, thereby adjusting the distance between the accelerating cylinder 13 and the discharge cavity to a suitable level. Subsequently, a certain voltage (about 2kV) is applied to the anode cylinder 4 through an external circuit, resulting in glow discharge. Under the combined action of the electric field and magnetic field, the upper cathode 3 and the lower cathode 10 emit electrons into the cavity, ionizing the neutral gas inside the anode cylinder 4. The negative ions generated by ionization move towards the anode cylinder 4 under the action of the electric field force. Then, the ions are drawn out through the second radial lead-out hole 18 on the side of the anode cylinder 4 and the first radial lead-out hole 15 on the side of the insulator 11 and enter the accelerating cylinder 12. At this time, the accelerating cylinder 12 is subjected to a positive high voltage (about 100kV). Under the action of the accelerating electric field, the generated negative ions are radially accelerated and drawn out to bombard the copper target 14, producing neutrons.

Claims

1. A neutron tube structure for a radially extractable Penning ion source with an adjustable accelerating electrode, comprising a sleeve (5), characterized in that, An anode cylinder (4) is provided at one end of the sleeve (5). An insulator (11) is embedded in the outer side of the cylinder body of the anode cylinder (4). A first radial lead-out hole (15) is provided in the middle of the cylinder body of the anode cylinder (4). A second radial lead-out hole (18) is provided on the side of the insulator (11) at the same position as the first radial lead-out hole (15). An acceleration cylinder (12) is provided on the outer side of the second radial lead-out hole (18) and coaxially with the insulator (11). A copper target (14) is provided at the tail end of the acceleration cylinder (12). The top end of the anode cylinder (4) is provided with an upper cathode (3), an upper permanent magnet (2), and an upper washer (1) in sequence; the bottom end of the anode cylinder (4) is provided with a lower cathode (10), a lower permanent magnet (9), and a lower washer (8) in sequence. The acceleration cylinder (12) is placed on a support frame (17) located at the other end of the sleeve (5). The inner side of the support frame (17) is connected to one end of the corrugated expansion tube (13), and the other end of the corrugated expansion tube (13) is connected to the inner side of the flange (16). The flange (16) is fixed to one end of the sleeve (5) by a screw (6) and a nut (7). The sleeve (5), the first radial lead-out hole (15), the second radial lead-out hole (18), the flange (16), the acceleration cylinder (12), and the copper target (14) are coaxial.

2. The neutron tube structure of a radially extracted Penning ion source with an adjustable accelerating electrode according to claim 1, characterized in that, The first radial lead-out hole (15) and the second radial lead-out hole (18) have the same diameter.

3. The neutron tube structure of a radially extracted Penning ion source with an adjustable accelerating electrode according to claim 1, characterized in that, The two ends of the corrugated expansion tube (13) are respectively sealed and welded to the flange (16) and the support frame (17); the tail end of the acceleration cylinder (12) is sealed and welded to the flange (16).

4. The neutron tube structure of a radially extracted Penning ion source with an adjustable accelerating electrode according to claim 1, characterized in that, The acceleration cylinder (12) and the copper target (14) are fixed together by threads, and there is a gap between the head end of the acceleration cylinder (12) and the support frame (17).

5. The neutron tube structure of a radially extracted Penning ion source with an adjustable accelerating electrode according to claim 1, characterized in that, The insulator (11) is made of ceramic material, and the upper washer (1) and lower washer (8) are made of rubber material.

6. The neutron tube structure of a radially extracted Penning ion source with an adjustable accelerating electrode according to claim 1, characterized in that, The corrugated expansion tube (13) is made of aluminum, the sleeve (5) and nut (7) are made of alloy, and the flange (16) and acceleration cylinder (12) are made of stainless steel.

7. The neutron tube structure of a radially extracted Penning ion source with an adjustable accelerating electrode according to claim 1, characterized in that, The anode cylinder (4), insulator (11) and the upper cathode (3), upper permanent magnet (2), upper washer (1) disposed at the top of the anode cylinder (4) and the lower cathode (10), lower permanent magnet (9), lower washer (8) disposed at the bottom of the anode cylinder (4) are coaxial.

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