Performances of microwave driven compact neutral beam sources of different plasma excitation configurations have been compared in producing directed low energy atomic beams for biomolecular structural analyses. The beam sources include unique impedance matching systems in themselves for reducing the size of the source; a multi-turn spiral antenna successfully excited a hydrogen plasma in a 4 mm inner diameter Al 2 O 3 tube by 2.45 GHz microwave power. A combination of a mirror magnetic field and electron cyclotron resonance has been found effective to realize a source operation at a low operating pressure (∼10 −3 Pa). This magnetic field configuration produced a hydrogen plasma with the optical emission spectrum predominated by atomic lines indicating a high degree of dissociation. The plasma excited in this type of source exhibited a mode transition like behavior which was not confirmed in other source geometries.

中文翻译：

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微波激发低能原子氢

在生产用于生物分子结构分析的定向低能原子束中，已经比较了不同等离子体激发配置的微波驱动紧凑型中性束源的性能。束源本身包括独特的阻抗匹配系统，可减小束源的尺寸；多匝螺旋天线通过2.45 GHz微波功率成功激发了内径为4 mm的Al 2 O 3管中的氢等离子体。已经发现镜磁场和电子回旋共振的组合对于在低工作压力（〜10 -3 Pa）下实现源操作是有效的。这种磁场结构产生了氢等离子体，其氢辐射光谱主要由原子线表示，表明离解程度高。