A. Kobets

POSITRON ANNIHILATION SPECTROSCOPY AT LEPTA FACILITY

The Low Energy Positron Toroidal Accumulator (LEPTA) at JINR proposed for generation of positronium in flight can be used for positron annihilation spectroscopy (PAS) [1]. The positron injector of the LEPTA facility can generate continuous a slow positron beam with the intensity up to 1∙107s-1 at the energy in the range of a few eV to 100 keV and width of the spectrum 1 – 2 eV. The injector is based on radioactive 22Na isotope. The solid neon is used as a moderator to generate monochromatic beam. The parameters of the positron beam allow scanning the condensed matter in depth up to 10 microns with resolutions less than 10 nanometers and investigating layered structures for microelectronics and properties of a surface.

The LEPTA Facility for Fundamental Studies of Positronium Physics and Positron Spectroscopy

At present time the Low Energy Positron Toroidal Accumulator (LEPTA) at JINR is under commissioning with circulating positron beam. The LEPTA facility is a small positron storage ring equipped with the electron cooling system and positron injector. The maximum positron energy is of 10 keV. The storage ring is aimed for generation of direct fluxes of ortho-positronium (o-Ps), produced in recombination of the positron beam circulating in the ring with single pass cooling electron beam. The project has few goals: annihilation spectroscopy (PAS) to monitoring defects of nanometer sizes in materials as a function of depth managed by the positron energy in a rage of a few eV to 100 keV.

Realization of Positron Annihilation Spectroscopy at LEPTA Facility

The Positron Annihilation Spectroscopy (PAS) unit was created as a part of LEPTA project at JINR in Dubna. Currently works performed in PAS laboratory focus on studies of defects in solid state, especially on studying radiation damages in novel materials and semiconductors as a part of the international project “Novel Semiconductor for Fundamental and Applied Research”. This report aims to present a current status of realization and progress in PAS methods at LEPTA facility at JINR.