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
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 .......