Microwave drive cesium-free negative hydrogen ion source

Abstract

The invention provides a negative hydrogen ion source, in particular to a high-current microwave drive cesium-free negative hydrogen (H-) ion source of a 2.45 GHz microwave drive and full permanent magnet structure. Plasma is generated through 2.45 GHz microwaves. Ion source magnetic fields are all generated through permanent magnets. An H- generating region is of a shoulder structure made of tantalum, and small-aperture and lateral deflection magnetic fields are adopted in the H- generating region. A large number of excited state hydrogen molecules (H2*) are generated through discharge of the 2.45 GHz microwaves, high-energy electrons cannot enter the H- generating region through the proper lateral magnetic fields, and passed low-energy electrons generate H- in the H- generating region through interaction with H2*. The probability that H- is generated on the surface of the H- generating region through the shoulder structure made of tantalum is increased. The aperture of the H- generating region is small, it is avoided that the microwaves heat the electrons in the region, the lateral magnetic fields of the region deflect to lead out the electrons in beam current, and then H- ion beam current with high current intensity and low electron proportion is finally acquired. The negative hydrogen ion source is mainly used for providing negative hydrogen ions for an accelerator.

Description

technical field [0001] The invention relates to an ion source, in particular to an ion source which is driven by 2.45GHz microwaves, has no cesium, and has a full permanent magnet structure and can generate high-current negative hydrogen ion beams. Background technique [0002] Negative hydrogen ion refers to an ion formed by a hydrogen atom with an electron outside it, so it is negatively charged. Early negative hydrogen ion sources were used in tandem electrostatic accelerators. Now, negative hydrogen ion sources are widely used in cyclotrons, high-energy colliders, spallation neutron sources, and neutral beam injection in future fusion devices. With the continuous development of accelerators in the direction of high-current and high-power, the negative hydrogen ion sources are required to have strong current, high stability, and long life. Negative hydrogen ion (H - ) has an electron affinity of only 0.75eV, and it is easy to interact with energy-carrying electrons (&g...

AI Technical Summary

Problems solved by technology

This kind of ion source usually only needs 1-3kW microwave power when generating high-current ion beams, and has good stability and long life. However, the negative hydrogen ion source driven by 1-10MHz radio frequency usually requires tens of kW power, complex structure, Lifetime is limited by RF antenna life and often requires complex auxiliary cesium circulation system (cesium is a toxic element, flammable)

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