Date of Award

2014

Document Type

Thesis

Department

Physics

First Advisor

Erik Sánchez

Subjects

Microscopes -- Design, Microscopy -- Research, Rarefied gas dynamics

DOI

10.15760/honors.59

Abstract

A novel design for a high intensity micron-scale supersonic free-jet source is described. This design has been implemented in a scanning helium neutral atom microscope at Portland State University, but has not been otherwise investigated. It is proposed that removing the skimmer component of a free-jet source can, under correct operating conditions, allow a comparable intensity beam to be created at greatly reduced complexity. The dsmcFOAM OpenFOAM solver was used to model rarefied gas dynamics of skimmed and un-skimmed helium atom sources. This modeling suggests that gas-gas scattering and shock structures occur in un-skimmed sources but can be compensated for with small aperture diameters and high source flow rates. If the comparable operation of skimmed and un-skimmed sources can be demonstrated it will greatly reduce the cost and complexity of helium atom sources for neutral atom microscopy and other applications.

Comments

An undergraduate honors thesis submitted in partial fulfillment of the requirements for the degree of Bachelor of Arts in University Honors and Physics

Persistent Identifier

http://archives.pdx.edu/ds/psu/11972

Share

COinS