ALBA GARCÍA , A.

Positron annihilation spectroscopy (PAS) has proven to be a very useful technique for, e.g., the study of defects in materials and the characterization of polymer free-volume. Positron lifetime, Doppler broadening of the annihilation radiation (characterized by the so-called S parameter) and angular correlation of annihilation radiation (ACAR)...

An overview is given of the extension of the Delft variable energy positron (VEP) beam facility with equipment for in situ heating, cooling, 4-point bending, hydrogen permeation and gas ad- and absorption of bulk materials, surfaces and interfaces.

An electrostatic variable energy positron beam for studying defects in ceramic coatings, polymer films and MOS-devices is developed for operation in Doppler-broadening (DB) and positron annihilation lifetime (PAL) modes. In DB mode the implantation energy can be varied between 3 and 30 keV with a beam diameter on the target ranging from 0.4 to...