Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Improved Microwave-discharge Source for uv Photoemission



Theodore V. Vorburger, B Waclawski, D Sandstrom


A microwave-discharge uv light source has been improved to yield significant photon fluxes at 26.9 and 40.81 eV. In order to optimize the 26.9-eV (NeII) and 40.81-eV (HeII) radiation, the discharge was operated at ~2.5 Pa (0.019 Torr) in an external constant magnetic field of ~0.070 T (700 G), which, together with the oscillating electric field of the cavity, produces electron cyclotron resonance. When the discharge conditions were optimized for production of 40.81-eV photons, features near the Fermi energy in the photoemission distribution from W(100) for 40.81-eV photons are approximately 6% as intense as the corresponding features in the distribution for 21.22-eV photons. We estimate that under these conditions the flux of 40.81-eV photons is roughly 50% of the flux of 21.22-eV photons. Photoemission energy distributions with hv = 16.85, 21.22, 26.9, and 40.81 eV have been measured for saturated exposures of CO on W(100) at a temperature of ~80 K. The variation in these data with photon energy is important for making orbital assignments to the energy levels of adsorbed molecular CO.
Review of Scientific Instruments


Vorburger, T. , Waclawski, B. and Sandstrom, D. (1976), Improved Microwave-discharge Source for uv Photoemission, Review of Scientific Instruments (Accessed June 14, 2024)


If you have any questions about this publication or are having problems accessing it, please contact

Created April 1, 1976, Updated February 19, 2017