International Workshop on Physics with Positrons at Jefferson Lab (JPos17)

Session

Plenary 11

Sep 14, 2017, 1:00 PM

Room F113 (CEBAF Center)

Conveners

Plenary 11

• Tony Forest (Idaho State University)
• Farida Selim (Bowling Green State University)

114. Positron annihilation induced Auger electron spectroscopy (PAES) to investigate the Auger relaxation of deep valence holes in single layer graphene

Varghese Anto Chirayath (Department of Physics, University of Texas at Arlington, 76019)

9/14/17, 1:00 PM

Positron Applications

Oral Contribution

We discuss our recent report on the direct observation of a low-energy Auger electron emission process initiated by the creation of a deep valence hole in single layer graphene through positron annihilation. Here, an electron from a higher energy level in the valence band fills the valence hole created by positron-electron annihilation. The energy released because of this relaxation is...

26. Electronic structure probed with positronium: Theoretical viewpoint

Jan Kuriplach (Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic)

9/14/17, 1:25 PM

Positron Applications

Oral Contribution

Positronium can be very helpful when studying the electronic structure of materials. Indeed, the recent experiment [1], where the Ps emission from a copper (110) surface was examined, allowed for the precise determination of the electron chemical potential of copper by means of measuring the Ps affinity. This affinity ($A_{Ps}$) [1] is defined formally via the electron ($\Phi_-$) and positron...

6. Historical survey of beta-particle interaction experiments with asymmetric matter.

J. David Van Horn (University of Missouri-Kansas City)

9/14/17, 1:50 PM

Positron Applications

Oral Contribution

Asymmetry is a basic property found at multiple scales in the universe [1]. Asymmetric molecular interactions are fundamental to the operation of biological systems in both signaling and structural roles. Other aspects asymmetry are observed and useful in many areas of science and engineering and have been studied since the discovery of chirality in tartrate salts [2]. The observation of...

115. Spin Polarized Core Hole Generation in Magnetic Structures using Spin-Polarized Positrons.

Ali R. Koymen (University of Texas at Arlington)

9/14/17, 2:15 PM

Positron Applications

Oral Contribution

The ability of positrons to create polarized core holes stems from the fact that the annihilation rate for spin singlet collisions is 1115 times faster than for spin triplet collisions and thus ~558 times faster with an electron of opposite spin. It is therefore possible to use the inherent polarization of positron beams to create polarized core holes with a net polarization approximately...