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The Center for Bright Beams, A National Science Foundation Science and Technology Center

New analyzer for studying photoemission

A mostly blue background with a yellow and green circle in the middle.
Showing Ag 111 surface state. More in caption.

A chart with a mostly blue background. On the x-axis is k x (1/A°), the y-axis is labeled Energy (meV). A dotted line parabola with the bottom of the curve at the bottom middle of the graph follows a yellow glowing arc.

Surface state of Ag(111) measured at the photoemission threshold using the meV scale energy analyzer.

S. Karkare, J. Feng, J. Maxson, H. A. Padmore

Measuring 3-D energy-momentum distributions of photoemitted electrons with milli electron volts(meV) of energy is crucial for investigating photoemission process that occur close to threshold during the generation of bright electron beams. Based on the time-of-flight technique, CBB researchers have developed a novel electron energy-momentum analyzer capable of measuring such low energy 3-D energy-momentum distributions of photoemitted electrons with sub-meV energy resolution allowing us to probe these low energy photoemission processes for the first time.