阅读说明：本技术 一种应用于负氢束的紧凑型气体中性化靶室结构 (Compact gas neutralization target chamber structure applied to negative hydrogen beam ) 是由 闫逸花 王忠明 曹可江 吕伟 王茂成 杨业 王迪 刘卧龙 王敏文 赵铭彤 陈伟 于 2020-05-21 设计创作，主要内容包括：本发明公开了一种应用于负氢束的紧凑型气体中性化靶室结构。该结构包括气体靶、气体靶腔室、进气管、进气管接口、上游真空差分系统以及下游真空差分系统；上游真空差分系统和下游真空差分系统结构相同,且以气体靶腔室的中轴线对称设置；上游真空差分系统包括多级真空差分腔室,第1级真空差分腔室至倒数第二级真空差分腔室采用一个腔室,且通过多个折弯隔板分割构建,该种结构设计使得中性化靶室与加速器束线进行匹配时,引入其真空系统在束流方向的长度大幅度的缩短,解决了现有中性化靶室与加速器匹配时由于空间限制导致的束线物理设计和工程实施难,且不利于靶前及靶后束流传输效率的问题。(The invention discloses a compact gas neutralization target chamber structure applied to negative hydrogen beams. The structure comprises a gas target, a gas target chamber, a gas inlet pipe interface, an upstream vacuum differential system and a downstream vacuum differential system; the upstream vacuum differential system and the downstream vacuum differential system have the same structure and are symmetrically arranged by the central axis of the gas target chamber; the upstream vacuum differential system comprises a plurality of stages of vacuum differential chambers, a chamber is adopted from the 1 st stage of vacuum differential chamber to the penultimate stage of vacuum differential chamber, and the chamber is divided and constructed by a plurality of bending partition plates, when the neutral target chamber is matched with an accelerator beam line by the structural design, the length of the vacuum system in the beam direction is greatly shortened, the problems that the beam line physical design and engineering implementation are difficult due to space limitation when the existing neutral target chamber is matched with an accelerator, and the beam transmission efficiency before and after the target is not favorable are solved.)

1. A compact gas neutralization target chamber structure applied to negative hydrogen beams is characterized in that:

the device comprises a gas target, a gas target chamber, a gas inlet pipe interface, an upstream vacuum differential system and a downstream vacuum differential system;

the upstream vacuum differential system and the downstream vacuum differential system have the same structure and are symmetrically arranged by the central axis of the gas target chamber;

the upstream vacuum differential system comprises a first chamber and a second chamber which are sequentially connected according to the flow direction of the beam; the first chamber is divided into N + 1-stage vacuum differential chambers by arranging N bending partition plates; the second chamber is used as an N +2 stage vacuum differential chamber and is communicated with the upstream beam pipeline interface; the first-stage vacuum differential chamber is communicated with the gas target chamber and each two adjacent stages of vacuum differential chambers through gas resistance pipes; each stage of vacuum differential chamber is connected with a molecular pump through a gate valve; wherein N is more than or equal to 1;

the gas inlet pipe is installed along the central axis of the gas target cavity, the gas target is installed at one end in the gas target cavity, and the gas inlet pipe interface is installed at one end outside the gas target cavity.

2. The compact gas-neutralizing target chamber structure for negative hydrogen beams according to claim 1, wherein: the bending partition plate comprises an inclined section, a first straight section and a second straight section; one end of the inclined section is fixedly connected with the inner wall of one side of the first cavity close to the gas target cavity, the other end of the inclined section is connected with one end of the first straight section, the other end of the first straight section is vertically and fixedly connected with one end of the second straight section, and the other end of the second straight section is fixedly connected with the inner wall of one side of the first cavity far away from the gas target cavity; the air resistance pipe is installed on the first straight section, and the central axis of the air resistance pipe in each bent partition plate is collinear with the central axis of the gas target.

3. The compact gas-neutralizing target chamber structure for negative hydrogen beams according to claim 2, wherein: the gate valve and the molecular pump are arranged at positions which meet the condition that the gas flow direction is vertical to the beam direction when the molecular pump is used for pumping the hole.

4. The compact gas-neutralizing target chamber structure for negative hydrogen beams according to claim 3, wherein: the difference ratio of each stage of air resistance pipe is 0.01-0.1.

5. The compact gas-neutralizing target chamber structure for negative hydrogen beams according to claim 4, wherein: the gas resistance pipe is installed on the first straight section of gas target chamber lateral wall, the baffle of bending and the first chamber lateral wall through flange plate to between flange plate and the gas target chamber lateral wall, fixed flange dish with all be equipped with O type sealing washer between the first straight section and between fixed flange dish and the first chamber lateral wall.

6. The compact gas-neutralizing target chamber structure for negative hydrogen beams according to claim 5, wherein: the gas-bearing gas.

7. The compact gas-neutralizing target chamber structure for negative hydrogen beams according to claim 6, wherein: the device also comprises a needle valve arranged at the inlet of the air inlet pipe and a first resistance gauge arranged on the air inlet pipe.

8. The compact gas-neutralizing target chamber structure for negative hydrogen beams according to claim 7, wherein: the vacuum plasma generating device also comprises a second resistance gauge on the gas target chamber and an ionization gauge arranged on each stage of vacuum differential chamber.

9. The compact gas-neutralizing target chamber structure for negative hydrogen beams according to claim 8, wherein: the pumping speed of the molecular pump connected with the 1 st to the N +1 th vacuum differential chambers is 1000L/s, and the pumping speed of the molecular pump connected with the N +1 th vacuum differential chambers is 350L/s.

10. The compact gas-neutralizing target chamber structure for negative hydrogen beams according to claim 9, wherein: the gas target chamber is cylindrical, the first chamber is rectangular, and the second chamber is cylindrical.

Technical Field

The invention relates to a neutralization target chamber, in particular to a compact gas neutralization target chamber structure applied to negative hydrogen beams.

Background

When neutral hydrogen atom beams are generated by negative hydrogen ions in a particle accelerator, the neutral hydrogen atom beams can be obtained by solid stripping or gas stripping. When solid stripping is adopted, the problems that the service life of the stripped foil is limited and the foil needs to be replaced from time to time exist; the gas target can maintain the mass thickness of the gas target at a constant value by means of real-time gas supplement, so that stable neutralization efficiency is achieved.

In order to avoid that negative hydrogen ions are stripped before entering a gas target chamber and neutral hydrogen atoms leaving the gas target are further stripped by gas molecules of a downstream pipeline to be changed into protons, the vacuum on the upstream and downstream beam pipelines of the gas target needs to be quickly raised to a high level. The vacuum degree on the accelerator beam line is higher, and is generally 1E^-5～1E^-6Pa magnitude, and the vacuum degree of the gas target is low, usually about several Pa, so that the transition from the gas target to the vacuum of the beam pipeline needs to be realized by using a gas resistance pipe.

Because the vacuum of the gas target and the beam pipeline is usually 5-6 orders of magnitude different, a very long air resistance pipe is needed to be used, the length of the pipeline along the beam line direction is too long, and therefore the transmission of upstream negative hydrogen ions and downstream neutral hydrogen atomic beams is not facilitated, and meanwhile, extra burden is brought to physical design and engineering implementation of a neutral beam line.

Disclosure of Invention

The invention provides a compact gas neutralization target chamber structure applied to negative hydrogen beams, aiming at solving the problems that when the existing gas neutralization target chamber is matched with an accelerator beam line, the introduced vacuum system formed by a gas resistance pipe and a vacuum pump is longer, the beam line physical design and engineering implementation are not facilitated, and the beam flow transmission efficiency before and after the target is not facilitated.

The technical scheme provided by the invention is as follows: the invention provides a compact gas neutral target chamber structure applied to negative hydrogen beams, which comprises a gas target, a gas target chamber, a gas inlet pipe interface, an upstream vacuum differential system and a downstream vacuum differential system, wherein the gas target chamber is provided with a gas inlet pipe;

the upstream vacuum differential system and the downstream vacuum differential system have the same structure and are symmetrically arranged by the central axis of the gas target chamber;

the upstream vacuum differential system comprises a first chamber and a second chamber which are sequentially connected according to the flow direction of the beam; the first chamber is divided into N + 1-stage vacuum differential chambers by arranging N bending partition plates; the second chamber is used as an N +2 stage vacuum differential chamber and is communicated with the upstream beam pipeline interface; the first-stage vacuum differential chamber is communicated with the gas target chamber and each two adjacent stages of vacuum differential chambers through gas resistance pipes; each stage of vacuum differential chamber is connected with a molecular pump through a gate valve; wherein N is more than or equal to 1;

the gas inlet pipe is installed along the central axis of the gas target cavity, the gas target is installed at one end in the gas target cavity, and the gas inlet pipe interface is installed at one end outside the gas target cavity.

Furthermore, the bending partition plate comprises an inclined section, a first straight section and a second straight section; one end of the inclined section is fixedly connected with the inner wall of one side of the first cavity close to the gas target cavity, the other end of the inclined section is connected with one end of the first flat section, the other end of the first flat section is vertically and fixedly connected with one end of the second flat section, and the other end of the second flat section is fixedly connected with the inner wall of one side of the first cavity far away from the gas target cavity; the air resistance pipe is installed on the first straight section, and the central axis of the air resistance pipe in each bent partition plate is collinear with the central axis of the gas target.

Furthermore, the difference ratio of each stage of air resistance pipe is 0.01-0.1.

Furthermore, in order to make better use of space for the layout of the neutral target chamber, the gate valve and the molecular pump are arranged at positions which meet the condition that the gas flow direction is vertical to the beam flow direction when the molecular pump is used for evacuating the hole.

Further, in order to carry out vacuum isolation between the first-stage vacuum differential chamber and the gas target chamber and between each stage of vacuum differential chamber, the gas resistance pipe is installed on the side wall of the gas target chamber, the first straight section of the bent partition plate and the side wall of the first chamber through a fixed flange plate, and O-shaped sealing rings are arranged between the fixed flange plate and the side wall of the gas target chamber, between the fixed flange plate and the first straight section and between the fixed flange plate and the side wall of the first chamber. Further, the neutralization target chamber structure also comprises a roots pump which is used for pumping away the gas carrier overflowing from the gas target.

Further, the above-mentioned neutralization target chamber structure still includes the needle valve of setting in the intake pipe entrance and sets up the vacuum gauge on the intake pipe.

Further, the above-mentioned neutralization target chamber structure also includes a resistance gauge on the gas target chamber, and an ionization gauge disposed on each stage of vacuum differential chamber.

Furthermore, the pumping speed of the molecular pump connected with the 1 st to the N +1 st vacuum differential chambers is 1000L/s, and the pumping speed of the molecular pump connected with the N +1 st vacuum differential chambers is 350L/s.

The invention has the beneficial effects that:

the invention adopts the multistage vacuum differential systems symmetrically arranged at the upper and lower streams of the gas target chamber, and the vacuum differential chamber from the 1 st stage to the penultimate stage is constructed by dividing one chamber through a plurality of bent partition plates, so that the length of the vacuum system in the beam direction is greatly shortened when the neutral target chamber is matched with the accelerator beam, and the problems that the beam physical design and engineering implementation are difficult and the beam transmission efficiency before and after the target is not favorable due to space limitation when the existing neutral target chamber is matched with the accelerator are solved.

Drawings

Fig. 1 is a schematic structural diagram of the embodiment.

Fig. 2 is a top view of fig. 1.

Fig. 3 is a sectional view taken along the line a of fig. 2.

Fig. 4 is a partial enlarged view of the gas barrier tube.

The reference numbers are as follows:

the vacuum valve comprises a 1-gas target, a 2-gas target chamber, a 3-gas inlet pipe, a 4-gas inlet pipe interface, a 5-upstream vacuum differential system, a 6-downstream vacuum differential system, a 7-first chamber, a 8-second chamber, a 9-bent partition plate, a 10-first-stage vacuum differential chamber, a 11-second-stage vacuum differential chamber, a 12-third-stage vacuum differential chamber, a 13-inclined section, a 14-first straight section, a 15-second straight section, a 16-gas resistance pipe, a 17-fixed flange plate, an 18-O-shaped sealing ring, a 19-gate valve, a 20-molecular pump, a 21-roots pump, a 22-needle valve, a 23-first resistance gauge, a 24-second resistance gauge and a 25-ionization gauge.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should also be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

The invention provides a specific embodiment of a compact gas neutralization target chamber structure applied to negative hydrogen beams, which comprises a gas target 1, a gas target chamber 2, a gas inlet pipe 3, a gas inlet pipe interface 4, an upstream vacuum differential system 5 and a downstream vacuum differential system 6, as shown in fig. 1 to 3;

the gas inlet pipe 3 is arranged along the central axis of the gas target chamber 2, one end positioned in the gas target chamber 2 is provided with the gas target 1, and the other end positioned outside the gas target chamber 2 is provided with the gas inlet pipe connector 4; in this embodiment, the gas target chamber is designed to be cylindrical;

the upstream vacuum differential system 5 and the downstream vacuum differential system 6 have the same structure and are symmetrically arranged by the central axis of the gas target chamber 2; since the upstream vacuum differential system 5 and the downstream vacuum differential system 6 have the same structure, for the sake of space saving, the embodiment is only described by taking the upstream vacuum differential system as an example;

the upstream vacuum differential system 5 includes a first chamber 7 and a second chamber 8 (in this embodiment, the first chamber 7 is rectangular, and the second chamber is cylindrical) which are connected in sequence in the flow direction of the beam; the first chamber 7 is divided into N + 1-stage vacuum differential chambers by arranging N bending partition plates 9; the second chamber 8 is used as an N +2 stage vacuum differential chamber and is communicated with the upstream beam pipeline interface; n is greater than or equal to 1, where N is 1 in this embodiment, the upstream vacuum differential system has a total three-stage vacuum differential chamber, which is a first-stage vacuum differential chamber 10, a second-stage vacuum differential chamber 11, and a third-stage vacuum differential chamber 12 in sequence according to the flow direction of the beam, and the following structures are all described by taking the three-stage vacuum chamber as an example (when the value of N can also be determined according to the vacuum magnitude difference between the gas target and the beam pipeline):

in this embodiment, the specific structure of the bending partition plate 8 includes an inclined section 13, a first straight section 14, and a second straight section 15; one end of the inclined section 13 is fixedly connected with the inner wall of one side of the first chamber 7 close to the gas target chamber 2, the other end of the inclined section is connected with one end of the first straight section 14, the other end of the first straight section 14 is vertically and fixedly connected with one end of the second straight section 15, and the other end of the second straight section 15 is fixedly connected with the inner wall of one side of the first chamber 7 far away from the gas target chamber, so that the first chamber 7 is divided into two independent vacuum differential chambers (namely a first-stage vacuum differential chamber 10 and a second-stage vacuum differential chamber 11);

the first stage vacuum differential chamber 10 is communicated with the gas target chamber 2, the first stage vacuum differential chamber and the second stage vacuum differential chamber, and the second stage vacuum differential chamber and the third stage vacuum differential chamber through a gas resistance pipe 16; specifically, the method comprises the following steps: the gas resistance pipe 16 communicated with the first-stage vacuum differential chamber 10 is arranged on the gas target chamber 2, the gas resistance pipe 16 communicated with the first-stage vacuum differential chamber 10 and the second-stage vacuum differential chamber 11 is arranged on the first straight section 14 of the bending partition plate 9, and the gas resistance pipe 16 communicated with the second-stage vacuum differential chamber 11 and the third-stage vacuum differential chamber 12 is arranged on the side wall of the first chamber 7; and the central axis of each stage of air resistance pipe 16 is collinear with the central axis of the gas target 1, and the difference ratio of each stage of air resistance pipe 16 is 0.01-0.1.

As shown in fig. 4, in order to perform vacuum isolation between the first stage vacuum differential chamber 10 and the gas target chamber 2, the gas barrier tube 16 is mounted on the sidewall of the gas target chamber 2, the first straight section 14 of the bent partition plate 9, and the sidewall of the first chamber 7 through a fixed flange 17, and O-rings 18 are respectively disposed between the fixed flange 17 and the sidewall of the gas target chamber 2, between the fixed flange 17 and the first straight section 14 of the bent partition plate 9, and between the fixed flange 17 and the sidewall of the first chamber 7.

Each stage of vacuum differential chamber is connected with a molecular pump 20 through a gate valve 19, so that the gradual increase of the vacuum degree is realized, specifically, a molecular pump with high pumping speed (the pumping speed is about 1000L/s) is arranged on the first stage of vacuum differential chamber and the second stage of vacuum differential chamber, and a small molecular pump (the pumping speed is about 350L/s) is arranged on the third stage of vacuum differential chamber; in order to make better use of space in the layout of the neutralization target chamber, the gate valve 19 and the molecular pump 20 are arranged at positions such that the gas flow direction is perpendicular to the beam direction when the molecular pump evacuates the hole.

The gas target chamber 2 is also provided with a roots pump 21 for pumping away gas load overflowing from the gas target, the inlet of the gas inlet pipe 3 is provided with a needle valve 22 and a vacuum gauge 23 arranged on the gas inlet pipe 3, the gas target chamber 2 is provided with a resistance gauge 24, and each stage of vacuum differential chamber is provided with an ionization gauge 25.

According to the specific description of the structure of the neutralization target chamber in the above embodiments, it can be seen that the target chamber has the following characteristics:

1. the structure of the neutral target chamber adopts three-stage vacuum differential systems at the upstream and the downstream of the beam, when the neutral target chamber is matched with an accelerator beam by adopting a chamber which is constructed by dividing a plurality of bent partition plates in the 1 st-stage vacuum differential chamber and the second-stage vacuum differential chamber, the multiplexing of three sections of spaces (a gas target chamber, a first-stage differential chamber and a second-stage differential chamber) is realized along the beam direction, a proper space is also provided for an outer side molecular pump interface, the length of the chamber along the beam direction is greatly compressed, the compact structural design is realized, the difficulty of beam physical design and the influence on engineering implementation are reduced, the influence of upstream vacuum on negative hydrogen beams in front of the target is reduced, the influence of downstream vacuum on neutral hydrogen atomic beams behind the target is reduced, and the maximum transmission efficiency of each section of beam is realized.

The difference ratio of each stage of air resistance tube is 0.01-0.1, the sizes of the air resistance tubes selected in the embodiment are d is larger than or equal to 15mm and smaller than or equal to 20mm in inner diameter and L is larger than or equal to 18mm and smaller than or equal to 67mm in length, vacuum transition from a gas target to beam current vacuum can be realized within a short distance, the requirement on beam spot size is considered, and the influence on beam loss is reduced.

2. Each stage of air resistance pipe is fixedly installed through an O-shaped sealing ring and a fixed flange disc, so that vacuum isolation among different vacuum chambers is realized.

3. A roots pump is arranged below the gas target chamber, so that most of gas load overflowing from the gas target can be pumped away; the first-stage and second-stage vacuum differential chambers are provided with molecular pumps with high pumping speed (pumping speed is about 1000L/s), the third-stage differential chamber is provided with small molecular pumps (pumping speed is about 350L/s), and the vacuum degree of the gas target beam can be improved step by matching with the size of the differential tubes, so that the vacuum degree of the gas target beam can be improved within a short distance.

4. The inlet of the air inlet pipe can accurately control the air inlet flow through a needle valve, a first resistance gauge 23 is arranged on the air inlet pipe, and the mass thickness of the gas target can be effectively estimated through monitoring the air pressure.

5. The second resistance gauge 24 is arranged on the gas target cavity, so that low vacuum monitoring in the cavity can be realized, and calculation of the diffusion length of the gas target is facilitated; the ionization gauges 25 are respectively arranged on the first-stage vacuum differential chamber, the second-stage vacuum differential chamber and the third-stage vacuum differential chamber, so that high vacuum monitoring can be realized.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.