| 摘要 |
An apparatus for producing a beam of ionized clusters includes a source that emits a beam of clustered and unclustered atoms through a nozzle and a cold cathode ionizer that ionizes the clusters. The ionizer is positioned in close proximity to the nozzle and the beam as it is emitted from the nozzle. A plasma is formed in the beam adjacent the nozzle when secondary electrons emitted from the cathode are accelerated and injected into the beam, resulting in the ionization of atoms and clusters. The cathode is preferably formed, at least in part, of a material that efficiently emits secondary electrons when impacted by ionized atoms extracted from the plasma to impact against the cathode, and the secondary electrons are injected into the plasma to renew the process. The ionized clusters remain in the beam and proceed to their target.
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