阅读说明：本技术 一种基于电感探针拾取束流相位信号的腔体结构 (Cavity structure for picking up beam phase signals based on inductance probe ) 是由 汪洋 于 2019-11-16 设计创作，主要内容包括：本发明涉及一种基于电感探针拾取束流相位信号的腔体结构,包括筒体状的腔体外导体、腔体内导体,腔体外导体的左端盖、右端盖均与束流运输管道相连通,腔体内导体的左、右端分别与腔体外导体两端连通的束流运输管道相对应,腔体内导体的右端面与腔体外导体的右端盖之间相接触形成短路端,腔体内导体的左端面与腔体外导体的左端盖之间具有水平间距形成开路端,电感式感应探针伸入腔体外导体与腔体内导体之间的环形空腔,并与腔体外导体的右端盖相连接。本发明为非阻拦式的腔体结构,可以实时拾取束流的相位信息,并且可以大大降低加速器设备周围的环境剂量,同时克服了加速器设备空间有限的问题,提高了束流相位信号拾取装置的信噪比。(The invention relates to a cavity structure for picking up beam phase signals based on an inductance probe, which comprises a cylindrical cavity outer conductor and a cylindrical cavity inner conductor, wherein a left end cover and a right end cover of the cavity outer conductor are communicated with a beam flow conveying pipeline, the left end and the right end of the cavity inner conductor correspond to the beam flow conveying pipeline communicated with two ends of the cavity outer conductor respectively, the right end surface of the cavity inner conductor is contacted with the right end cover of the cavity outer conductor to form a short-circuit end, a horizontal space is formed between the left end surface of the cavity inner conductor and the left end cover of the cavity outer conductor to form an open-circuit end, and the inductance probe extends into an annular cavity between the cavity outer conductor and the cavity inner conductor and is connected with the right end cover of the cavity. The non-blocking cavity structure can pick up the phase information of the beam in real time, greatly reduce the environmental dose around the accelerator equipment, overcome the problem of limited space of the accelerator equipment and improve the signal-to-noise ratio of the beam phase signal pick-up device.)

1. The utility model provides a cavity structure based on inductance probe picks up beam phase signal, includes cavity outer conductor (2), cavity inner conductor (1) of barrel form, its characterized in that: the left end cover (21) and the right end cover (22) of the cavity outer conductor (2) are communicated with the beam flow conveying pipeline (3), the left end and the right end of the cavity inner conductor (1) correspond to the beam flow conveying pipeline (3) communicated with the two ends of the cavity outer conductor (2) respectively, a short circuit end (7) is formed by the contact between the right end face (12) of the cavity inner conductor (1) and the right end cover (22) of the cavity outer conductor (2), a horizontal distance is formed between the left end face (11) of the cavity inner conductor (1) and the left end cover (21) of the cavity outer conductor (2) to form an open circuit end (6), and the inductive sensing probe (4) stretches into an annular cavity (5) between the cavity outer conductor (2) and the cavity inner conductor (1) and is connected with the right end cover (22) of the cavity outer conductor (2).

2. The cavity structure for picking up the beam phase signal based on the inductance probe according to claim 1, wherein: the beam transport pipeline (3) and the cavity inner conductor (1) are the same in diameter, and the cavity outer conductor (2) and the cavity inner conductor (1) are coincident with the axis of the beam transport pipeline (3).

3. The cavity structure for picking up the beam phase signal based on the inductance probe as claimed in claim 2, wherein: the diameters of the beam transport pipeline (3) and the inner conductor (1) of the cavity are 190-210 mm, and the wall thickness is 4-6 mm.

4. The cavity structure for picking up the beam phase signal based on the inductance probe as claimed in claim 3, wherein: the diameters of the beam transport pipeline (3) and the conductor (1) in the cavity are both 200mm, and the wall thickness is both 5 mm.

5. The cavity structure for picking up the beam phase signal based on the inductance probe according to claim 1, wherein: the vertical distance between the cavity outer conductor (2) and the cavity inner conductor (1) is 46-48 mm, the horizontal distance between the left end cover (21) of the cavity outer conductor (2) and the left end face (11) of the cavity inner conductor (1) is 8.5-9.5 mm, the length of the cavity outer conductor (2) is 260-264 mm, and the length of the cavity inner conductor (1) is 250-254 mm.

6. The cavity structure for picking up the beam phase signal based on the inductance probe as claimed in claim 5, wherein: the vertical distance between the cavity outer conductor (2) and the cavity inner conductor (1) is 47mm, the horizontal distance between the left end cover (21) of the cavity outer conductor (2) and the left end face (11) of the cavity inner conductor (1) is 10mm, the length of the cavity outer conductor (2) is 262mm, and the length of the cavity inner conductor (1) is 252 mm.

7. The cavity structure for picking up the beam phase signal based on the inductance probe as claimed in claims 5 to 6, wherein: the eigenfrequency of the cavity structure is 142.4 MHz.

8. The cavity structure for picking up the beam phase signal based on the inductance probe according to the claims 1 to 6, characterized in that: the side wall of the cavity outer conductor (2) is communicated with a probe guide pipe (23) close to a right end cover (22), and the inductive sensing probe (4) is positioned in the probe guide pipe (23).

Technical Field

The invention relates to the technical field of cyclotrons, in particular to a cavity structure for picking up beam phase signals based on an inductance probe.

Background

In the application of the cyclotron for proton treatment, the requirements of the treatment process on the intensity, the stability and the extraction efficiency of beams are higher. In the actual operation process of the cyclotron, factors such as heat loss of a high-frequency system, external temperature change, instability of a power supply and the like can affect the magnetic field strength of the cyclotron, cause detuning of the magnetic field, and affect the stability and extraction efficiency of the beam current, which are adverse factors for cyclotron equipment, startup operators for daily maintenance and patients needing radiotherapy.

Therefore, in order to study beam phase stabilization control of the isochronous accelerator, an auto-tuning beam phase stabilization system was realized. It is necessary to develop and design a cavity structure for picking up a beam phase signal, and to consider the problems of reducing the environmental dose around the accelerator device, and the limited space of the accelerator device.

Disclosure of Invention

The invention aims to provide a cavity structure for picking up beam phase signals based on an inductance probe, the non-blocked cavity structure can pick up the phase information of beams in real time, greatly reduce the environmental dose around accelerator equipment, overcome the problem of limited space of the accelerator equipment, and improve the signal-to-noise ratio of a beam phase signal picking device.

The above object of the present invention is achieved by the following technical solutions:

a cavity structure based on an inductance probe for picking up beam phase signals comprises a cylindrical cavity outer conductor and a cylindrical cavity inner conductor, wherein a left end cover and a right end cover of the cavity outer conductor are communicated with a beam transport pipeline, the left end and the right end of the cavity inner conductor correspond to the beam transport pipeline communicated with the two ends of the cavity outer conductor respectively, the right end face of the cavity inner conductor is in contact with the right end cover of the cavity outer conductor to form a short-circuit end, a horizontal distance is reserved between the left end face of the cavity inner conductor and the left end cover of the cavity outer conductor to form an open-circuit end, and an inductance type induction probe extends into an annular cavity between the cavity outer conductor and the cavity inner conductor and is connected with the right end cover of the cavity outer conductor.

By adopting the technical scheme, the cavity structure for picking up the beam phase signal is arranged on a beam transport pipeline of the cyclotron, the specific size parameters of the cavity outer conductor and the cavity inner conductor of the cavity structure adopt the optimized design, when the beam passes through the cavity structure, the resonance of the cavity structure can be excited, the inductive induction probe at the short-circuit end of the cavity structure can pick up the beam phase signal, the beam phase signal is subjected to phase discrimination with the reference phase signal of the high-frequency accelerating electric field, the exciting current of a main magnet power supply is adjusted through the output result curve of the phase discrimination, so that the magnetic field intensity of the cyclotron is stabilized, the condition that the extracted beam particles are accelerated every time when passing through the accelerating electric field is ensured, and the stability and the extraction efficiency of the beam extracted by the cyclotron are improved. The cavity structure for picking up the beam phase signals is used for picking up high-precision beam phase signals, belongs to research equipment of a beam phase stability control system, and provides necessary conditions for picking up beams with different energy.

The invention is further configured to: the beam transport pipeline and the inner conductor of the cavity have the same diameter, and the axial leads of the outer conductor of the cavity, the inner conductor of the cavity and the beam transport pipeline are coincided.

By adopting the technical scheme, the diameters of the inner conductor of the cavity structure and the beam transport pipeline are kept consistent, so that when the extracted beam passes through the cavity structure for picking up the beam phase signal, the resonance of the cavity of the beam phase probe can be excited, the beam phase signal is picked up, and conditions are provided for the research of beam phase stability control of the isochronous accelerator.

The invention is further configured to: the diameters of the beam transport pipeline and the conductor in the cavity are 190-210 mm, and the wall thickness is 4-6 mm.

By adopting the technical scheme, the diameters of the conductor in the cavity and the beam transportation pipeline are kept consistent, so that when the extracted beam passes through the cavity structure for picking up the beam phase signal, the resonance of the cavity of the beam phase probe can be excited, and the beam phase signal is picked up.

The invention is further configured to: the diameters of the beam transport pipeline and the conductor in the cavity are both 200mm, and the wall thickness is both 5 mm.

By adopting the technical scheme, the diameters of the beam transport pipeline and the inner conductor of the cavity are limited to 200mm, and the wall thickness is 5mm, so that when the extracted beam passes through the cavity structure for picking up the beam phase signal, the resonance of the cavity structure can be excited, and the beam phase signal can be picked up.

The invention is further configured to: the vertical distance between the cavity outer conductor and the cavity inner conductor is 46-48 mm, the horizontal distance between the left end cover of the cavity outer conductor and the left end face of the cavity inner conductor is 8.5-9.5 mm, the length of the cavity outer conductor is 260-264 mm, and the length of the cavity inner conductor is 250-254 mm.

By adopting the technical scheme, the vertical distance, the horizontal distance and the length of the outer conductor of the cavity structure for picking up the beam phase signal influence the eigen frequency of the cavity structure, the larger the vertical distance between the outer conductor of the cavity and the inner conductor of the cavity is, the smaller the eigen frequency of the cavity structure for picking up the beam phase signal is, the larger the horizontal distance between the outer conductor of the cavity and the inner conductor of the cavity is, namely, the larger the capacitance at the open end is, the larger the eigen frequency of the cavity structure for picking up the beam phase signal is, the longer the lengths of the outer conductor of the cavity and the inner conductor of the cavity are, and the smaller the eigen frequency of the cavity structure for picking up the beam phase signal.

The invention is further configured to: the vertical distance between the cavity outer conductor and the cavity inner conductor is 47mm, the horizontal distance between the left end cover of the cavity outer conductor and the left end face of the cavity inner conductor is 10mm, the length of the cavity outer conductor is 262mm, and the length of the cavity inner conductor is 252 mm.

By adopting the technical scheme, the cavity structure for picking up the beam phase signals limits the size parameters, and the eigenfrequency of the cavity structure for picking up the beam phase signals is ensured to be 142.4 MHz.

The invention is further configured to: the eigenfrequency of the cavity structure is 142.4 MHz.

By adopting the technical scheme, the eigenfrequency of the cavity structure for picking up the beam phase signals is 142.4MHz, the non-blocking cavity structure can realize real-time beam phase measurement, the environmental dose level around the accelerator equipment is ensured, and the cavity structure is particularly suitable for the research of the beam phase stability control of the isochronous accelerator.

The invention is further configured to: the side wall of the cavity outer conductor is communicated with a probe guide pipe close to the right end cover of the cavity outer conductor, and the inductive sensing probe is positioned in the probe guide pipe.

By adopting the technical scheme, the inductive induction probe at the short-circuit end of the cavity structure can pick up a beam phase signal, phase discrimination is carried out on the beam phase signal and a reference phase signal of a high-frequency accelerating electric field, and the exciting current of the main magnet power supply is adjusted through an output result curve of the phase discrimination.

In conclusion, the beneficial technical effects of the invention are as follows:

1. the cavity structure for picking up the beam phase signal is arranged on a beam transport pipeline of the cyclotron, the specific size parameters of the cavity outer conductor and the cavity inner conductor of the cavity structure adopt the optimal design, when the beam passes through the cavity structure, the resonance of the cavity structure can be excited, the beam phase signal can be picked up by an inductive induction probe at the short-circuit end of the cavity structure, the beam phase signal and the reference phase signal of the high-frequency accelerating electric field are subjected to phase discrimination, the exciting current of a main magnet power supply is regulated through the output result curve of the phase discrimination, the magnetic field intensity of the cyclotron is stabilized, the condition that the extracted beam particles are accelerated every time when passing through the accelerating electric field is ensured, and the stability and the extraction efficiency of the beam extracted by the cyclotron are improved. The cavity structure for picking up the beam phase signals is used for picking up high-precision beam phase signals, belongs to research equipment of a beam phase stability control system, and provides necessary conditions for picking up beams with different energy.

2. The diameters of the inner conductor of the cavity structure and the beam transport pipeline are kept consistent, so that when the extracted beam passes through the cavity structure for picking up the beam phase signal, the resonance of the cavity of the beam phase probe can be excited, the beam phase signal is picked up, and conditions are provided for the research of the beam phase stability control of the isochronous accelerator; compared with the traditional picking mode, the cavity structure has small space structure, the signal-to-noise ratio is greatly improved, the non-blocking cavity structure can realize real-time measurement of beam phase signals, the environmental dose level around accelerator equipment is ensured, and the cavity structure is particularly suitable for research on beam phase stability control of an isochronous accelerator.

3. According to the invention, the larger the vertical distance between the outer conductor of the cavity and the inner conductor of the cavity is, the smaller the eigenfrequency of the cavity structure for picking up the beam phase signal is, the larger the horizontal distance between the outer conductor of the cavity and the inner conductor of the cavity is, namely, the larger the capacitance at the open end is, the larger the eigenfrequency of the cavity structure for picking up the beam phase signal is, the longer the lengths of the outer conductor of the cavity and the inner conductor of the cavity are, and the smaller the eigenfrequency of the cavity structure for picking up the beam phase signal is. The vertical distance, the horizontal distance and the length of the conductor outside the cavity between the conductor outside the cavity and the conductor inside the cavity have influence on the eigenfrequency of the cavity structure, and the eigenfrequency of the cavity structure for picking up the beam phase signals is 142.4 MHz.

Drawings

Fig. 1 is a schematic diagram of the structure of the chamber of the present invention.

Fig. 2 is an electromagnetic field profile of the cavity structure of the present invention.

Fig. 3 is a magnetic field distribution diagram of the cavity structure of the present invention.

Fig. 4 is a diagram showing the pickup end voltage of the cavity structure for picking up the beam phase signal when the 230MeV and 300nA beam lines are used as excitation.

The reference signs are: 1. a conductor within the cavity; 11. a left end face; 12. a right end face; 2. a cavity outer conductor; 21. a left end cap; 22. a right end cap; 23. a probe catheter; 3. a beam transport pipeline; 4. an inductive sensing probe; 5. an annular cavity; 6. opening a circuit end; 7. and (4) short-circuit ends.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

Referring to fig. 1, the invention discloses a cavity structure for picking up beam phase signals based on an inductance probe, comprising a cylindrical cavity outer conductor 2 and a cylindrical cavity inner conductor 1, wherein a left end cover 21 and a right end cover 22 of the cavity outer conductor 2 are both communicated with a beam transport pipeline 3, the left end and the right end of the cavity inner conductor 1 are respectively corresponding to the beam transport pipelines 3 communicated with two ends of the cavity outer conductor 2, a right end face 12 of the cavity inner conductor 1 is contacted with the right end cover 22 of the cavity outer conductor 2 to form a short circuit end 7, a horizontal distance is arranged between a left end face 11 of the cavity inner conductor 1 and the left end cover 21 of the cavity outer conductor 2 to form an open circuit end 6, the inductance probe 4 extends into an annular cavity 5 between the cavity outer conductor 2 and the cavity inner conductor 1 and is connected with the right end cover 22 of the cavity outer conductor 2, the side wall of the cavity outer conductor 2 is communicated with a probe conduit 23 close to, an inductive sensing probe 4 is located within the probe guide 23;

the eigenfrequency of the cavity structure is 142.4MHz, the diameter of the beam transport pipeline 3 is the same as that of the conductor 1 in the cavity, and the axial leads of the outer conductor 2 of the cavity, the conductor 1 in the cavity and the beam transport pipeline 3 are coincident; the diameters of the beam transport pipeline 3 and the conductor 1 in the cavity are both 200mm, and the wall thickness is both 5 mm; the vertical distance between the cavity outer conductor 2 and the cavity inner conductor 1 is 47mm, the horizontal distance between the left end cover 21 of the cavity outer conductor 2 and the left end face 11 of the cavity inner conductor 1 is 10mm, the length of the cavity outer conductor 2 is 262mm, and the length of the cavity inner conductor 1 is 252 mm.

The experimental design steps of the specific dimensional parameters of the cavity structure in this embodiment are as follows:

a) as shown in fig. 1, a model of a cavity structure for picking up beam phase signals is established through CST software, the diameter of a beam transport pipeline of an accelerator and a conductor 1 in the cavity are kept consistent, the diameter is 200mm, the wall thickness reaches 5mm, and the vertical distance, the horizontal distance and the length of the outer conductor 2 between the outer conductor 2 of the cavity and the conductor 1 in the cavity have influence on the eigenfrequency of the cavity structure;

b) the influence of a certain specific variable on the eigenfrequency of the cavity structure is researched by CST software by adopting a control variable method;

c) fixing the horizontal distance between the cavity outer conductor 2 and the cavity inner conductor 1 and the length of the cavity outer conductor 2, changing the vertical distance between the cavity outer conductor 2 and the cavity inner conductor 1, and obtaining the experimental conclusion: the larger the vertical distance between the cavity outer conductor 2 and the cavity inner conductor 1 is, the smaller the eigenfrequency of the cavity structure for picking up the beam phase signal is;

d) the horizontal distance between the cavity outer conductor 2 of the cavity structure open end 6 and the cavity inner conductor 1 determines the capacitance of the open end 6, the length of the cavity inner conductor 1 is fixed, and then the change of the eigenfrequency of the cavity structure is observed by changing the length of the cavity outer conductor 2, and the obtained experimental conclusion is as follows: the larger the horizontal distance between the cavity outer conductor 2 and the cavity inner conductor 1 is, namely the larger the capacitance of the open end 6 is, the larger the eigenfrequency of the cavity structure for picking up the beam phase signal is;

e) the capacitance of the open end 6 of the cavity structure is fixed, the length of the outer conductor 2 of the cavity and the length of the inner conductor 1 of the cavity are changed, and the obtained experimental conclusion is as follows: the longer the lengths of the cavity outer conductor 2 and the cavity inner conductor 1 are, the smaller the eigenfrequency of the cavity structure for picking up the beam phase signal is;

f) through simulation experiments of the influence of the three variables on the eigenfrequency of the cavity structure, the size close to the eigenfrequency of 142.4MHz is preferably selected, namely the vertical distance between the cavity outer conductor 2 and the cavity inner conductor 1 is 47mm, the horizontal distance between the left end cover 21 of the cavity outer conductor 2 and the left end face 11 of the cavity inner conductor 1 is 10mm, the length of the cavity outer conductor 2 is 262mm, the length of the cavity inner conductor 1 is 252mm, and the electromagnetic field distribution of the cavity structure for picking up beam phase signals after simulation is shown in FIG. 2;

g) in a Particle Wakefield mode of CST software, a beam line of 230MeV and 300nA is set as excitation, and the velocity of the beam is calculated by the following formula:wherein W is the beam energy in eV,beta is calculated to be about 0.7, and assuming that the length of the beam line is 30mm, the charge amount is calculated to be about 7.95E-10C. The sampling end of the inductive sensing probe 4 is connected to a 500hm load, the voltage value of the inductive sensing probe is observed at the load end, and the simulation result is shown in fig. 4. As can be seen from fig. 4, the CST voltage of the cavity structure for picking up the beam phase signal can be simulated by using the CST software, which illustrates that the non-blocking cavity structure can be used for measuring the beam phase signal.

The embodiments of the present invention are preferred embodiments of the present invention, and the scope of the present invention is not limited by these embodiments, so: all equivalent changes made according to the structure, shape and principle of the invention are covered by the protection scope of the invention.