阅读说明：本技术 一种中子产生靶 (Neutron generation target ) 是由 童剑飞 欧阳华甫 朱凌波 张锐强 赵崇光 梁天骄 于 2021-06-23 设计创作，主要内容包括：本发明涉及产生加速器驱动的靶体技术领域,尤其涉及一种具有高效冷却功能、温度与束斑监控功能的用于加速器驱动的高功率中子产生靶；所述的中子产生靶包括顺序贴合连接的靶材层、粒子迁移层、微通道基底层和盖板层,形成一体式的多层结构靶体,靶体上设置有多组热电偶组件；所述的微通道基底层表面加工有多排肋片,相邻的肋片间形成微小散热通道；本发明解决了靶体周围的高剂量辐射环境下红外成像摄像头无法长期工作的问题；利用微小散热通道结构对中子产生靶进行冷却,有利于对于质子束斑形状的预测,实现靶材的温度监测；采用均匀分布的热电偶,其距离靶材表面的距离一致,以此形成均匀测量的温度场,有利于束斑形状预测。(The invention relates to the technical field of target bodies driven by an accelerator, in particular to a high-power neutron generation target for driving the accelerator, which has the functions of efficient cooling and monitoring temperature and beam spot; the neutron generation target comprises a target material layer, a particle migration layer, a micro-channel substrate layer and a cover plate layer which are sequentially attached and connected to form an integrated multi-layer structure target body, and a plurality of groups of thermocouple assemblies are arranged on the target body; a plurality of rows of fins are processed on the surface of the micro-channel basal layer, and a micro heat dissipation channel is formed between adjacent fins; the invention solves the problem that the infrared imaging camera can not work for a long time under the high-dose radiation environment around the target body; the small heat dissipation channel structure is used for cooling the neutron generation target, so that the prediction of the spot shape of the proton beam is facilitated, and the temperature monitoring of the target material is realized; the thermocouples which are uniformly distributed are consistent in distance from the surface of the target material, so that a uniformly measured temperature field is formed, and the shape prediction of the beam spot is facilitated.)

1. A neutron production target, characterized by: the neutron generation target comprises a target material layer, a particle migration layer, a micro-channel substrate layer and a cover plate layer which are sequentially attached and connected to form an integrated multi-layer structure target body, and a plurality of groups of thermocouple assemblies are arranged on the target body; the surface of the micro-channel basal layer is provided with a plurality of rows of fins, and a micro heat dissipation channel is formed between adjacent fins.

2. The neutron generating target of claim 1, wherein: thermocouple subassembly equipartition set up on the target structure, run through the target body from the apron layer until closing to the target layer.

3. The neutron production target of claim 1 or 2, wherein: the thermocouple assembly comprises a thermocouple and a sleeve, the sleeve penetrates through the target body from the cover plate layer until the sleeve is close to the target material layer, and the thermocouple is inserted into the corresponding sleeve so as to be close to the target material as possible and deduce the temperature of the target material.

4. The neutron generating target of claim 1, wherein: the thermocouple penetrates through the target body cover plate layer and the surface fins of the micro-channel basal layer to reach the bottom of the micro-channel basal layer.

5. The neutron generating target of claim 1, wherein: the bottom surface of the cover plate layer is attached to the micro-channel basal layer and is connected with the micro-channel basal layer, the cover plate layer is sealed in a welding or thread fastening mode to surround the micro-channel basal layer at the bottom, and the cover plate layer and the micro-channel basal layer form a cavity structure.

6. The neutron production target of claim 5, wherein: the two ends of the cavity are provided with an inlet and an outlet of a cooling working medium, and an expansion domain is arranged between the inlet and the outlet and the micro-channel structure, so that the flow of fluid entering and exiting each channel is equal or close, and uniform heat exchange is realized.

7. The neutron generating target of claim 1, wherein: the upper surface of the micro-channel basal layer is jointed and connected with the cover plate layer, and the lower surface of the micro-channel basal layer is jointed, diffused and welded or connected in a film coating mode with the particle migration layer.

8. The neutron generating target of claim 1, wherein: the height dimension of the particle migration layer and the target material layer is lower than the dimension of the central cooling area of the substrate layer of the micro-channel.

9. The neutron generating target of claim 1, wherein: the fins are arranged at equal intervals and made of heat exchange materials such as copper, aluminum, nickel, iron or alloy thereof, graphite, heat conduction graphite sheets and the like.

10. The neutron generating target of claim 1, wherein: the working medium inlet and outlet of the micro-channel substrate layer are combined with the micro heat dissipation channels to carry out flaring design, so that the flow distribution in each micro heat dissipation channel is the same or close to the flow distribution in each micro heat dissipation channel.

11. The neutron generating target of claim 1, wherein: the target material layer adopts one of lithium, carbon, beryllium, aluminum and tungsten as a raw material.

12. The neutron production target of claim 11, wherein: when the target material layer adopts aluminum as a raw material, neutrons are not generated or are less generated, and residual radioactive elements are less used as a debugging target body.

Technical Field

The invention relates to the technical field of targets for driving an accelerator, in particular to a high-power neutron generation target for driving the accelerator, which has an efficient cooling function and a temperature and beam spot monitoring function.

Background

When particles or rays generated by an accelerator bombard a neutron generation target, particularly low-energy protons, high unit heat flux density, high heat load power and other conditions such as boron neutron capture cancer treatment device, the device adopts protons as incident particles, the energy of the protons is between 2MeV and 10MeV, the power of the proton beam is up to more than 30kW, meanwhile, the range of the protons in metal is short, and the heat flux density is over 100kW/cm 2. Because the proton range is low, the proton irradiated beam current measuring element can be deposited in the beam current measuring element to cause the burning of the beam current measuring element, and therefore, the specific beam spot distribution is difficult to obtain; in addition, when the proton beam power is high and the distribution is concentrated, the heat flow density is high, a low-melting-point material is used as a target material such as a lithium target, the melting point is only 180 ℃, the problem of heat removal of the lithium target is large, and therefore the temperature operation condition of the target body needs to be monitored in real time to ensure uniform irradiation of the proton beam spot and avoid target body damage caused by melting of a lithium layer.

The neutron generation target provided by the invention of the CN106385757A patent detects the temperature of each point on the target body through a temperature sensor, and comprises thermocouple thermometers for detecting the incidence surface of the target body, the edge of the incidence surface of the target body, the vicinity of the joint of the target body and a cooling seat and a cavity pipeline, wherein a plurality of groups of thermometers finish temperature and beam spot monitoring together. In addition, the inside independent cavity that is of cooling seat, with the vacuum cavity of target body not intercommunicate, the target body is kept apart with the cooling water each other, realizes target body cooling function through the fin and the condenser tube that links to each other in the cooling seat of target body bottom. However, there are the following problems: firstly, the temperature measuring wires of the thermocouples in the scheme are led out from the vacuum side and need to be led out through a vacuum wall penetrating piece, the arrangement difficulty is high, and the installation difficulty is high due to the arrangement of the thermocouples at a plurality of different positions; secondly, under the condition of high beam current power, a lead or a thermocouple of a temperature measuring element deep into the center of the beam current can be directly irradiated by the beam current to cause over-high temperature and cause burnout; thirdly, the temperature measuring element goes deep into the center of the beam in vacuum, and the beam directly irradiates the temperature measuring element but not the target body, so that the neutron yield is reduced; fourthly, the temperature measuring elements directly penetrate into the cooling seat from the periphery, damage the cooling structure of the temperature measuring elements to reduce the heat exchange effect, and limit the number of measuring points at the same time, so that the distribution of the reaction beam spots cannot be accurate.

Disclosure of Invention

In view of the above-mentioned shortcomings, the present invention is directed to a neutron generating target, which includes a device for generating neutrons by irradiating the neutron target with particles such as protons, heavy ions, or rays, and more particularly, to a high power neutron generating target for accelerator driving, which has an efficient cooling function, a temperature and beam spot monitoring function.

The technical scheme adopted by the invention is as follows: a neutron generation target comprises a target material layer, a particle migration layer, a micro-channel substrate layer and a cover plate layer which are sequentially attached and connected to form an integrated multi-layer structure target body, wherein a plurality of groups of thermocouple assemblies are arranged on the target body; the surface of the micro-channel basal layer is provided with a plurality of rows of fins, and a micro heat dissipation channel is formed between adjacent fins.

Thermocouple subassembly equipartition set up on the target structure, run through the target body from the apron layer until closing to the target layer.

The thermocouple assembly comprises a thermocouple and a sleeve, the sleeve penetrates through the target body from the cover plate layer until the sleeve is close to the target material layer, and the thermocouple is inserted into the corresponding sleeve so as to be close to the target material as possible and deduce the temperature of the target material.

The thermocouple penetrates through the target body cover plate layer and the surface fins of the micro-channel basal layer to reach the bottom of the micro-channel basal layer.

The bottom surface of the cover plate layer is attached to the micro-channel basal layer and is connected with the micro-channel basal layer, the cover plate layer is sealed in a welding or thread fastening mode to surround the micro-channel basal layer at the bottom, and the cover plate layer and the micro-channel basal layer form a cavity structure.

The two ends of the cavity are provided with an inlet and an outlet of a cooling working medium, and an expansion domain is arranged between the inlet and the outlet and the micro-channel structure, so that the flow of fluid entering and exiting each channel is equal or close, and uniform heat exchange is realized.

The upper surface of the micro-channel basal layer is jointed and connected with the cover plate layer, and the lower surface of the micro-channel basal layer is jointed, diffused and welded or connected in a film coating mode with the particle migration layer.

The height dimension of the particle migration layer and the target material layer is lower than the dimension of the central cooling area of the substrate layer of the micro-channel.

The fins are arranged at equal intervals and made of heat exchange materials such as copper, aluminum, nickel, iron or alloy thereof, graphite, heat conduction graphite sheets and the like.

The working medium inlet and outlet of the micro-channel substrate layer are combined with the micro heat dissipation channels to carry out flaring design, so that the flow distribution in each micro heat dissipation channel is the same or close to the flow distribution in each micro heat dissipation channel.

The target material layer adopts one of lithium, carbon, beryllium, aluminum and tungsten as a raw material.

When the target material layer adopts aluminum as a raw material, neutrons are not generated or are less generated, and residual radioactive elements are less used as a debugging target body.

The invention has the beneficial effects that: according to the invention, the plug-in thermocouple assembly is used for replacing an infrared imaging camera to measure the temperature of the target material, so that the problem that the infrared imaging camera cannot work for a long time in a high-dose radiation environment around the target body is solved; the small heat dissipation channel structure is used for cooling the neutron generation target, the fins are made of heat exchange materials such as copper, aluminum and alloys thereof or graphite, and the heat removal efficiency is high; flaring design is carried out by combining the micro heat dissipation channels with the inlets and the outlets of the micro heat dissipation channels, so that the flow distribution in each micro channel is the same or close to each other, the heat removal capacity of the micro channels is uniformly distributed, and the prediction of the spot shape of a proton beam is facilitated; the thermocouple assembly is extended into the bottom of the micro-channel substrate layer through the target body cover plate layer and the fins on the surface of the micro-channel substrate layer so as to be close to the target material layer as much as possible, realize the temperature monitoring of the target material, simultaneously avoid the influence on a heat exchange structure and avoid the direct irradiation of particles when the target material is measured through vacuum; the drilling depths in the micro-channel basal layer are consistent and uniformly distributed, so that the micro-channel basal layer is beneficial to processing and installation; the thermocouples which are uniformly distributed are uniformly spaced from the surface of the target material, so that a uniformly measured temperature field is formed, the beam spot shape prediction is facilitated, the central positions of all heat exchange flow channels formed among the fins are uniformly provided with the raised structures which are equal in height along the flowing direction of the cooling working medium, the raised structures can increase disturbance, and the heat exchange effect is enhanced.

Drawings

FIG. 1 is a schematic structural view of the present invention.

Fig. 2 is a schematic exploded view of the present invention.

FIG. 3 is a side view of the present invention.

Fig. 4 is a schematic view of the present invention in a longitudinal sectional view.

Fig. 5 is a schematic view of the present invention in a transverse cross-section.

Fig. 6 is a schematic structural diagram of a micro-channel substrate layer according to an embodiment of the invention.

Fig. 7 is a schematic structural diagram of a micro-channel substrate layer according to a second embodiment of the present invention.

Reference is made to the accompanying drawings in which: 1-target layer, 2-particle transport layer, 3-microchannel base layer, 4-cover plate layer, 5-thermocouple assembly, 31-fins, 32-outlet, 33-inlet, 34-protrusion structure.

Detailed Description

The following detailed description of the embodiments of the invention is provided in conjunction with the drawings of the specification:

as shown in fig. 1-5, a neutron generation target includes a target material layer 1, a particle migration layer 2, a microchannel substrate layer 3, and a cover plate layer 4, which are sequentially attached and connected to form an integrated target body with a multilayer structure, and a plurality of thermocouple assemblies 5 are disposed on the target body; the surface of the microchannel substrate layer 3 is processed with a plurality of rows of fins 31, and micro heat dissipation channels, referred to as microchannels, are formed between adjacent fins 31.

In the invention, the neutron generating target detects the temperature of each point on the target body through the plug-in thermocouple assembly 5, and deduces whether the temperature of the target material exceeds the limit or not by using the temperature value of each point on the target body layer, thereby realizing real-time temperature monitoring and avoiding the operation accidents of the target body.

According to the invention, the beam spot shape is judged by utilizing the temperature values of the plurality of thermocouple assemblies 5 which are uniformly distributed, so that the beam spot monitoring function is realized; wherein the sleeve of the thermocouple assembly 5 is connected through the cover plate layer 4, the microchannel base layer 3, the particle transport layer 2 and the target layer 1, and the thermocouple is inserted into the corresponding sleeve to approach the target as close as possible and infer the target temperature.

According to the invention, the cover plate layer 4 encloses the microchannel substrate layer 3 at the bottom in a closed manner by welding or screw fastening, and forms a cavity structure, multiple rows of fins 31 arranged at equal intervals are processed on the surface of the microchannel substrate layer 3, a micro heat dissipation channel is formed between adjacent fins 31, an inlet 33 and an outlet 32 of a cooling working medium are arranged at two ends of the cavity, an expansion area is arranged between the inlet 33 and the outlet 32 and the microchannel structure, so that the flow of fluid entering and exiting each channel is equal or close to the flow of fluid entering and exiting each channel to form uniform heat exchange, the microchannel substrate layer 3 is connected with the particle migration layer 2, the particle migration layer 2 is connected with the target material layer 1, and the sizes of the particle migration layer 2 and the target material layer 1 are lower than that of a central cooling area of the microchannel substrate.

When the beam spot irradiates the target, the neutron generated in the target damages partial energy and damages the whole energy in the particle migration layer 2, and simultaneously, a large amount of energy deposited in the particle migration layer 2 is transmitted to the micro-channel substrate layer 3 in a heat conduction mode, so that the micro-channel substrate layer 3 which is tightly connected is utilized for efficient thermal deposition and removal; cooling working media uniformly flow through each channel of the microchannel after expanding the flow section through the inlet 33, the heat dissipation channel structures distributed on the surface of the substrate at equal intervals form a uniform distribution effect on the working media, and further increase the heat exchange area through the microchannel, so that the heat exchange capacity of the working media is increased; finally, the cooling medium of each heat dissipation channel is collected at the outlet 32 at the other side and discharged.

At this time, the principle of judging the beam spot shape on the target surface is as follows: a uniformly distributed heat exchange structure is formed through the micro-channel, and the thermocouple enters the target body through the cover plate layer 4 at the rear part of the target body to measure the temperature so as to avoid, reduce or form a consistent temperature difference; when the beam spots are uniformly distributed, the temperature values of all thermocouples are kept consistent as the heat exchange structure and the thermal resistance are the same and the thermocouples are the same; when the beam deflection phenomenon occurs, the beam spot deflects, which causes the integral migration of the thermocouple temperature value. When the beam is not uniform and is locally focused, the temperature of the focused area of the beam is higher. Therefore, the beam offset direction and the beam focusing condition can be judged by comparing the thermocouple temperature values on the surface of the target, the offset degree focusing degree of the beam spot can be inferred by detecting the thermocouple temperature value in the center of the surface of the target, and the real-time condition of the beam spot on the surface of the target can be inferred by using a plurality of thermocouples together.

According to the invention, the plug-in thermocouple assembly 5 is used for replacing an infrared imaging camera to measure the temperature of the target material, so that the problem that the infrared imaging camera cannot work for a long time in a high-dose radiation environment around the target body is solved; the neutron generation target is cooled by utilizing a micro heat dissipation channel structure, and the fins 31 are made of heat exchange materials such as copper, aluminum and alloys thereof or graphite, so that the heat removal efficiency is high; flaring design is carried out by combining the micro heat dissipation channels with the inlet and outlet 33 of the micro heat dissipation channels, so that the flow distribution in each micro channel is the same or close to each other, the heat removal capacity of the micro channels is uniformly distributed, and the prediction of the spot shape of the proton beam is facilitated; the thermocouple assembly 5 is deeply inserted into the bottom of the micro-channel substrate through the target body cover plate layer 4 and the fins 31 on the surface of the micro-channel substrate layer 3 so as to be close to the target material layer 1 as much as possible, the temperature monitoring of the target material is realized, meanwhile, the influence on a heat exchange structure is avoided, and the direct irradiation of particles during the measurement of the target material through vacuum is avoided; the drilling depths in the micro-channel substrate layer 3 are consistent and uniformly distributed, so that the micro-channel substrate is beneficial to processing and installation; the thermocouples which are uniformly distributed are consistent in distance from the surface of the target material, so that a uniformly measured temperature field is formed, and the shape prediction of the beam spot is facilitated.

The first embodiment is as follows: lithium is used as a target material layer 1, wherein the target body fins 31 have the same height, specifically 3mm, the spacing is 1mm, and the width is 1 mm; the inlet and outlet 32 is a semicircular structure with the diameter of 40mm, and the distance between the periphery of the thermocouple is 20 mm.

As shown in fig. 1-6, a neutron generation target, the neutron generation target include target layer 1, particle migration layer 2, microchannel substrate layer 3 and apron layer 4 that the order laminating is connected, form the multilayer structure target body of integral type, apron layer 4 seal microchannel substrate layer 3 through welding or screw fastening's mode and surround in the bottom to constitute cavity structures, cavity structures both ends are provided with and supply the entry 33 and the export 32 that cooling working medium flows, have guaranteed to connect mechanical strength.

Wherein, microchannel stratum basale 3 is used for cooling target material layer 1, and microchannel stratum basale 3 surface finish has multirow fin 31, forms small heat dissipation channel between adjacent fin 31, and the cavity structures is used for holding fin 31 structure, is provided with multiunit thermocouple subassembly 5 on the target body for monitor target material surface temperature.

Wherein, thermocouple subassembly 5 equipartition set up in target body structure, run through the target body from cover plate layer 4 until approaching target material layer 1, the drilling is unified to microchannel stratum basale 3 and cover plate layer 4 structure, inserts the sleeve that one end is sealed in to corresponding drilling, fastens through welding or screw thread mode, later deepens its bottom with the thermocouple in each sleeve to this is close as far as possible and measures target material layer 1 temperature. Wherein the drilling holes are evenly distributed in a square shape and account for 25; one end of the sleeve is of a sealed structure, so that the sealing cooling water is prevented from leaking through the sleeve; the thermocouple external connection leads a signal through the back end of the sleeve and into the measurement system.

The cover plate layer 4 is tightly and hermetically surrounded on the micro-channel substrate layer 3 in a welding mode or in a threaded fastening mode, a cavity structure is formed, multiple rows of ribs 31 arranged at equal intervals are processed on the surface of the micro-channel substrate, the intervals between every two adjacent ribs 31 are equal, equidistant tiny heat dissipation channels are formed, and the lengths of the channels are the same along the flowing direction; an inlet 33 and an outlet 32 of a cooling working medium are arranged at the left end and the right end of the cavity, wherein the inlet 33 and the outlet 32 are distributed in a flaring manner and are communicated with the micro-channel structure of the cavity, the micro-channel substrate layer 3 is connected with the bottom of the particle migration layer 2 in a diffusion welding manner, when lithium is used as a target material, the particle migration layer 2 is connected with the particle migration layer 2 through a coating film, and the particle migration layer 2 is connected with the micro-channel structure in a diffusion welding manner; wherein the size of the central cooling area of the micro-channel substrate layer 3 is higher than that of the proton beam spot and the particle migration layer 2.

In the embodiment, under the high-power condition, the high-efficiency cooling heat exchange of the micro-channel is beneficial to reducing the temperature of the target body and improving the heat removal capability, and particularly, when low-melting-point target materials such as lithium targets and the like are adopted under the high-power condition, the melting of lithium is avoided through the real-time monitoring of the temperature and beam spots, so that the target body is damaged; meanwhile, the micro-channel technology is adopted to effectively cool the target body under the high heat flux density generated when the target body is generated by particle bombardment neutrons, and the energy deposition of the target body is removed in time; the method is characterized in that a straight pipe with a sealed bottom is arranged on the back cover plate layer 4 of the target body and penetrates through the fins 31 of the micro-channel to measure the temperature of the surface close to the target body, so that the influence of blocking in the channel is avoided, and the influence on a cooling structure is small; in practice, the temperature sensing element is placed through the fins 31 of the microchannel at the back of the neutron producing target to measure the true temperature close to the target material, closer to the target material; the uniform cooling capacity is provided for the target material through the uniform micro-channel structure and the uniformly distributed cooling working medium in the micro-channel, the uniform matrix type temperature measuring elements are combined for arrangement, the beam spot distribution feedback of the surface of the target produced by neutrons is realized through temperature distribution, and the reference is provided for beam adjustment of the accelerator.

Example two, lithium oxide was used as the target layer 1, wherein the target fins 31 were equal in height, specifically 5mm, 120mm in length, 2mm in width, and 2mm apart from each other for each fin 31.

The second embodiment is different from the first embodiment in that lithium is used as a target in the first embodiment, and even if heat dissipation is performed to a certain extent by the microchannel technology, melting of lithium due to too high temperature of the target is inevitable. In addition, the heat dissipation technology in the first embodiment adopts a conventional micro-channel structure, and when extreme conditions such as a high beam concentration degree occur, the heat dissipation effect may not achieve an ideal effect. In the second embodiment shown in fig. 7, lithium oxide is used as the target layer 1, wherein the target fins 31 have the same height, specifically 5mm, length 120mm, width 2mm, and the spacing between the fins 31 is 2 mm; the central position of each heat exchange flow channel formed between the fins 31 is provided with a bulge structure 34 along the flowing direction of the cooling working medium, the bulge structures are blade-shaped and are uniformly distributed between every two fins 31, six blade-shaped bulge structures 34 with equal height are uniformly distributed in the embodiment, the equal height can ensure the assembly performance and the sealing performance, the bulge structures 34 can increase the disturbance and enhance the heat exchange effect, specifically, the heat exchange effect is 1mm, and the distance between two adjacent bulge structures 34 is 20 mm.

In the second embodiment, lithium oxide is used as a target material, and feasibility of replacing lithium by the material is demonstrated in an AB-BNCT neutron target physical design analysis document, wherein although the yield of the neutron is reduced compared with that of lithium, the reduction range is not large, the melting point is remarkably improved from 180 ℃ to 1567 ℃, the heat resistance of the target material is fully improved, and the safe operation of a target body at high temperature is ensured. In addition, the flow velocity of the cooling working medium and the flowing turbulence intensity are increased by uniformly arranging the blade-shaped protruding structures in the micro-channel, so that the overall heat exchange effect of the micro-channel is further enhanced, and the heat dissipation requirement under a special working condition is met.

The target material can adopt one of lithium, carbon, beryllium, aluminum and tungsten, wherein when the aluminum is adopted, neutrons are not or less generated, and residual radioactive elements are less as a debugging target body; and a particle migration layer 2 is arranged between the target material and the target body micro-channel substrate layer 3, and the material of the particle migration layer is one of vanadium, tantalum and iron.

The above embodiments are only specific embodiments of the present invention, and the description thereof is specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications are possible without departing from the inventive concept, and such obvious alternatives fall within the scope of the invention.