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Transport of Intense, High-Brightness Ion Beams

强、高亮度离子束的传输

基本信息

批准号：
09044195
负责人：
SASAO Mamiko
金额：
$ 3.39万
依托单位：
National Institute for Fusion Sciences
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09044195/
关键词：
high brightness ion beam beam transport space charge effect Electrostatic quadruple lens perveance emittance emittance meter ヘリウム負イオン

项目摘要

While transporting high perveance beams, three effects primarily govern their trajectories and phase-space behavior, namely, the space charge force, the emittance, and the external focusing fields. A good understanding of these effects is warranted in order to design and build an efficient transport system. In the present collaborative work, an experimental study on the transport of a high perveance (beam energy < 20keV, beam current = 1 - 20 mA) HeィイD1+ィエD1 beam is carried out. An intense HeィイD1+ィエD1 ion source has been developed. An electrostatic quadruple (ESQ) transport system has been designed and built to transport the beams extracted from the source. Various diagnostic tools, such as emittance meters and beam profile monitors, are developed. In beam transport experiments using the ESQ lesnes initial settings of the applied voltage obtained from a beam envelope code. It has been confirmed that the ESQ lens system provides a good focusing property and that a set of focusing parameters has a reasonably large range of acceptance of beam parameters. The present experimental results also indicate that the ESQ system can transport HeィイD1+ィエD1 beams without any beam loss, and without any significant emittance growth over a length of about 70-cm when the normalized beam perveance is less than 0.003. Evidence of non-linear effects has been noted in the emittance diagram. Distortions in these emittance diagram are primarily due to chromatic aberrations when the beam approaches the boundary of the ESQ electrodes and the beams near the center and the peripheral regions experience significantly different focusing fields.

在传输高性能光束时，空间电荷力、发射度和外部聚焦场三种效应主要影响其轨迹和相空间行为。为了设计和建造一个高效的运输系统，有必要充分了解这些影响。本文对高性能（束流能量< 20keV，束流电流= 1 ~ 20ma） He γ γ γ + γ γ γ γ γ束流的输运进行了实验研究。研制了一种高强度的He γ γ γ + γ γ γ离子源。设计并建造了一个静电四重传输系统来传输从源中提取的光束。开发了各种诊断工具，如发射度计和光束轮廓监视器。在束流输运实验中，利用ESQ减少了从束流包络码中获得的施加电压的初始设置。结果表明，ESQ透镜系统具有良好的聚焦性能，且一组聚焦参数对光束参数的接受范围相当大。实验结果还表明，当归一化光束性能小于0.003时，ESQ系统可以传输He γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ。非线性效应的证据已在发射率图中指出。这些发射度图的畸变主要是由于光束接近ESQ电极边界时的色差造成的，靠近中心和外围区域的光束经历了明显不同的聚焦场。