Electron microscopic observations of Rb particles and pitting in 129Xe spin-exchange optical pumping cells.

Journal Article (Journal Article)

High-volume production of hyperpolarized 129Xe by spin-exchange optical pumping (SEOP) has historically fallen short of theoretical predictions. Recently, this shortfall was proposed to be caused by the formation of alkali metal clusters during optical pumping. However, this hypothesis has yet to be verified experimentally. Here, we seek to detect the presence of alkali particles using a combination of both transmission (TEM) and scanning (SEM) electron microscopy. From TEM studies, we observe the presence of particles exhibiting sizes ranging from approximately 0.2 to 1 μm and present at densities of order 10 s of particles per 100 square microns. Particle formation was more closely associated with extensive cell usage history than short-term ([Formula: see text]1 h) SEOP exposure. From the SEM studies, we observe pits on the cell surface. These pits are remarkably smooth, were frequently found adjacent to Rb particles, and located predominantly on the front face of the cells; they range in size from 1 to 5 μm. Together, these findings suggest that Rb particles do form during the SEOP process and at times can impart sufficient energy to locally alter the Pyrex surface.

Full Text

Duke Authors

Cited Authors

  • Flower, C; Freeman, MS; Plue, M; Driehuys, B

Published Date

  • July 14, 2017

Published In

Volume / Issue

  • 122 / 2

Start / End Page

  • 024902 -

PubMed ID

  • 28804157

Pubmed Central ID

  • PMC5505777

International Standard Serial Number (ISSN)

  • 0021-8979

Digital Object Identifier (DOI)

  • 10.1063/1.4991642


  • eng

Conference Location

  • United States