Positron Research

Positron physics and its applications is my main interest. Work on polymers, semiconductors, metals and alloys have been conducted for bulk and surface measurements.

The positron group in Qatar has three lifetime   spectrometers, dedicated to the study of metals and metal alloys as well   as the study of polymers and semiconductors. All spectrometers are of the   ‘fast-fast’ type and are linked to computers for data acquisition. Two use plastic scintillators and the third system uses BaF detectors.

We have studied materials of industrial importance, such as polymers, by a combination of positron techniques and other material science techniques to elucidate the effects of the size, fraction, and distribution of free volume and their influence on physical       properties. Many papers have been published from this work.

All lifetime systems are accompanied by Ge detectors for simultaneous Doppler Broadening measurements.

Low temperature measurements are made available through a closed cycle He cryocooler.

The positron beam system enables surface studies of many materials such as semiconductors,   conducting polymers, thin films etc. The Qatar Positron Beam incorporates a Na-22 source and Tungsten mesh moderator. it is a totally magnetically guided beam with energies ranging from 0-30keV.