All Physics Faculty Presentations

Title

Hemispherical grid retarding field analyzer for absolute measurement of secondary and back-scattered electron yields

Document Type

Contribution to Book

Journal/Book Title/Conference

Bulletin of the American Physical Society

Volume

46

Publication Date

2001

Abstract

Secondary and back-scattered electron yields can be measured with a variety of electron detectors. However, measurements of absolute yields are difficult with most collection schemes and normalization against a known standard is required. The design, construction and calibration of a custom two grid retarding field analyzer--similar to a standard LEED detector--is described in detail. The analyzer mounts on a 10 sample carousel and can rotate between each sample and different source beams in the UHV chamber. Electron, ion, and photo-induced secondary and back-scattered electron yields and emission energy spectra can be measured. To obtain accurate absolute electron yields, we have a theoretically determined correction algorithm, based on the materials and geometry of the analyzer, that compensates for currents lost to grid wires and those multiply scattered from other surfaces within the detector. Our experimental results for Au and graphitic carbons, relatively inert standard materials, are compared with published results and the uncertainties in our absolute measurements are discussed.

Comments

Bull. Am. Phys. Soc. 46(1) Part I, 443, (2001). American Physical Society March Meeting 2001, March 12 - 16, 2001, Seattle, Washington