Positron Annihilation Spectroscopy in Materials and Technical Details of Measurement Systems

Abstract

Being a very powerful method, Positron Annihilation Spectroscopy (PAS) has been widely used for investigation of defects type and concentration in materials in recent years. In this paper, we first report characteristics of a Positron Annihilation Lifetime Spectroscopy (PALS) system which has been made in an Iranian nuclear spectroscopy instrument company with corporation of Sistan and Baluchestan University for the first time. The system is working with a resolution better than 350ps and can be used for materials such as ceramics, glasses and insulator materials. Next, we report designing and development of the first slow positron beam in Iran and we explain its advantages for exploring defects in materials. Positron Source, moderator and vacuum chamber including positron beam tube and sample chamber, has been designed and prepared. Designing of extraction lenses and magnetic fields has been made using CST STUDIO software in order to optimum focusing and transition of beam.

Keywords

• slow positron beam system
• positron annihilation spectroscopy
• life time spectroscopy