Developing a spin polarized helium ion source for surface electronic structure studies

Development of a low energy spin polarized He$\sp+$ source for application in studies of electron spin correlations in ion neutralization at surfaces is described. The source is based on an optically pumped helium discharge. An rf discharge is used to produce metastable helium atoms in a clean pyrex glass cell. A 300 mW Ti:sapphire laser operating at 1.083 μm is used to optically pump the He(2$\sp3$S) atoms on the \rm 2\sp3S\sb1\leftrightarrow 2\sp3P\sb1 (D\sb1) transition to preferentially populate the \rm He(2\sp3S) M\sb{j}(M\sb{s}) = +1 or -1 magnetic sublevels. The electron spin polarization of the resulting atoms is measured using optical absorption. He(2$\sp3$S) polarizations of $\sim$60-70% can be routinely achieved. He$\sp+$ ions, which are produced in metastable-metastable collisions and therefore are expected to be polarized, are extracted from the discharge cell and are focused using a system of ion optics. The ion energy spread is large, $\sim$30-40 eV, but can be reduced to $\sim$3-4 eV by energy filtering. The resulting ion current, $\sim$0.5 nA, is sufficient to study spin dependences in a variety of ion-surface interactions.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

Masters

Discipline thesis:degree_discipline

Natural Sciences

Grantor

Rice University

Year dc:date.issued

1995

Author dc:creator

• Huang, Dajin

Advisor dc:contributor.advisor

• Dunning, F. B.

• Atomic physics

Statement dc:rights

• Copyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.

Language dc:language.iso

eng

Handle dc:identifier.uri

https://hdl.handle.net/1911/13961

OAI identifier oai:identifier

oai:repository.rice.edu:1911/13961