CN217883934U

CN217883934U - ECR negative hydrogen ion source

Info

Publication number: CN217883934U
Application number: CN202221703673.XU
Authority: CN
Inventors: 欧阳华甫; 傅世年; 曹秀霞; 肖永川; 吕永佳; 陈卫东; 刘盛进; 李辉
Original assignee: Institute of High Energy Physics of CAS; Spallation Neutron Source Science Center
Current assignee: Institute of High Energy Physics of CAS; Spallation Neutron Source Science Center
Priority date: 2022-07-01
Filing date: 2022-07-01
Publication date: 2022-11-22
Anticipated expiration: 2032-07-01

Abstract

The application relates to an ECR negative hydrogen ion source, wherein an electromagnet is arranged on the periphery of a discharge chamber of an ion source, and a scanning power supply is used for supplying power to the electromagnet. The electromagnet is an alternating electromagnet and provides a variable magnetic field. The invention has the following beneficial effects: the invention can solve the problem which is difficult to solve in the prior art through simple structural design, namely, the scanning power supply is used for supplying power to the electromagnet, the plasma electron temperature is controlled by controlling the scanning amplitude and the frequency of the output current of the power supply, and the collision cross section of negative hydrogen ions can be increased under proper electron temperature, namely, the charge exchange is promoted, more negative hydrogen ions are generated, and the ECR negative hydrogen ion source with high yield is realized.

Description

ECR negative hydrogen ion source

Technical Field

The invention relates to an ECR source, in particular to an ECR negative hydrogen ion source.

Background

An electron cyclotron resonance ion source (ECR-Electron cyclotron resonance) is a microwave source and is generally divided into a high-charge-state high-frequency ECR source and a single-charge-state high-current 2.45GHzECR source. The generation of the medium and high charge states is obtained by inelastic collisions of energetic electrons with the particles, the electrons gaining energy from the microwave field when they are in cyclotron motion around the magnetic field lines. Therefore, a high charge state ECR ion source requires a strong confinement magnetic field and a high microwave frequency to obtain high energy electrons. The 2.45GHzECR ion source is mainly used for generating single-charge state strong-current positive and negative ion beams, and can generate ultra-high-density plasma by using 2.45GHz microwaves and a magnetic field not more than 0.1T. Currently 2.45ghz ecr ion sources are widely used to generate either high flux high power proton beams or deuterium ion beams, both of which are positive ion beams.

The 2.45GHzECR ion source has the advantages of small volume, simple structure, convenient maintenance, relatively low manufacturing cost and the like. Although the ECR ion source has the advantages, the ECR ion source is only widely used for a proton source in practice because the electron temperature of the plasma cannot be controlled and the high negative hydrogen yield is difficult to obtain, and therefore the ECR negative hydrogen ion source capable of controlling the electron temperature of the plasma and improving the negative hydrogen yield is invented.

Disclosure of Invention

In view of the above-mentioned problem that it is practically difficult to realize ECR negative hydrogen ions having a large extraction amount, it is an object of the present invention to provide an ECR negative hydrogen ion source that confines charged particles by using a magnetic field. The technical scheme adopted by the invention is as follows: an ECR negative hydrogen ion source is characterized in that an electromagnet is arranged on the periphery of a discharge chamber of an ion source, and a scanning power supply is used for supplying power to the electromagnet.

The electromagnet is an alternating electromagnet and provides a variable magnetic field.

The invention has the following beneficial effects: the invention can solve the problem which is difficult to solve in the prior art through simple structural design, namely, the scanning power supply is used for supplying power to the electromagnet, the plasma electron temperature is controlled by controlling the scanning amplitude and the frequency of the output current of the power supply, and the collision cross section of negative hydrogen ions can be increased under proper electron temperature, namely, the charge exchange is promoted, more negative hydrogen ions are generated, and the ECR negative hydrogen ion source with high yield is realized.

Drawings

FIG. 1 is a schematic view showing the structure of an ECR negative hydrogen ion source in the present invention.

Fig. 2 is a waveform diagram of the magnetic field intensity generated by the electromagnet after the electromagnet is powered by the scanning power supply.

Reference is made to the accompanying drawings in which: 1-electromagnet, 2-discharge chamber.

Detailed Description

The following detailed description of the embodiments of the present invention is given by way of specific examples:

as shown in fig. 1-2, an electromagnet 1 is additionally arranged on the periphery of a discharge chamber 2 of an ion source to provide a magnetic field, a scanning power supply is used for supplying power to the electromagnet, the current control of the electromagnet is realized by controlling the scanning amplitude and frequency of the output current of the power supply, so that the magnetic field in the discharge chamber is controlled, the temperature control of plasma electrons is realized, the collision cross section of negative hydrogen ions is enlarged, and the yield of the negative hydrogen ions is improved.

The performance of an ion source is fundamentally determined by the nature of the plasma within the ionization chamber (discharge chamber), which is closely related to the following factors: the surrounding magnetic and electric field distribution; the surface condition of the discharge chamber and the associated effects that accompany it; working air pressure in the discharge chamber, etc.; the ion generation and elimination are a pair of closely-connected processes, in the ion source, the ionization is always enhanced to generate more ions and electrons, the loss of the ions is avoided as much as possible, the service life of the ions is prolonged, and the basic processes of the ion loss and the elimination are charge exchange, recombination and diffusion loss. The invention sets a variable magnetic field outside the discharge chamber 2, and supplies power to the electromagnet 1 by using a scanning power supply according to an electron cyclotron frequency formula omega _ce Where B is the magnetic field strength, m is the electron mass, and e is the charge carried by the electron, = eB/m, it is known that the electron cyclotron resonance frequency changes under a changing magnetic field, and this makes it possible to control the plasma electron temperature by the above-described control without the electron cyclotron resonance frequency and the electric field frequency coinciding with each other. More specifically, in the ECR negative hydrogen ion source of the present invention, the axial magnetic field required by the electron cyclotron resonance is provided by the electromagnet 1, the electromagnet 1 is powered by the scanning power supply, and since the generated variable magnetic field controls the electron temperature of the plasma by controlling the scanning amplitude and frequency of the output current of the power supply, the electron temperature of the plasma is suitable, the collision cross section of the negative hydrogen ions can be increased, and the charge exchange is promoted, thereby increasing the yield of the negative hydrogen ions in the discharge chamber 2.

In summary, according to the technical scheme of the invention, the scanning power supply is used for supplying power to the electromagnet, the scanning amplitude and frequency of the output current of the power supply are controlled, the plasma electron temperature is controlled, the collision cross section of negative hydrogen ions can be increased at a proper electron temperature, namely, the charge exchange is promoted, more negative hydrogen ions are generated, the influence of ion source extinction caused by the recombination and diffusion processes is indirectly weakened, only a small amount of negative hydrogen ions can be generated in the conventional ECR ion source in actual production, and the high-yield ECR negative hydrogen ion source is realized.

Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An ECR negative hydrogen ion source, comprising: an electromagnet is arranged on the periphery of a discharge chamber of the ion source, and a scanning power supply is used for supplying power to the electromagnet.

2. An ECR negative hydrogen ion source according to claim 1, wherein: the electromagnet is an alternating electromagnet and provides a variable magnetic field.