New materials : Conductivity mechanism in the super-ionics

This project uses the method of positron spectroscopy to detect vacancies in thermal equilibrium. These measuremetns were performed at the Schonland Research Institute for Nuclear Sciences at the Wits University.

Typical gamma spectrum from positron annihilation where the positrons are derived from a 22Na source
The region of the 511 keV annihilation radiation expanded. Note the high Compton background

At Schonland, a 2-dimensional spectrum can be obtained, taking both gamma rays in coincidence

This 2-dimensional spectrum has the Doppler broadeneing effect rotated away from the Compton background

If a cut is made on the area where the data resides, and only these events are used to construct the gamma energy spectrum ....

.... then the energy spectrum cleans up remarkably, allowing a more sensitive extraction of the physics !


Watch this space for more .......