Positrons (the antiparticles of electrons) and positronium (the
bound state of an electron and a positron) are currently employed in the exploration
of fundamental effects ranging from condensed matter physics to astrophysics as
well as in the diagnostics of living biological systems and of the electronic and
structural properties of industrially important materials. Our main research interests
are in atomic physics problems where beams of positrons and positronium with speeds
comparable to those of atomic electrons are contributing to the unravelling of general
collision phenomena as well as illuminating specific interactions and processes
such as exchange and annihilation.
Current hot topics of research worldwide include positron-induced
ion production (comprising ionization with and without Ps formation, annihilation,
etc), positron impact excitation (vibrational and electronic) and positronium scattering.
Measurements of differential ionization and positronium collisions are in their
infancy. UCL is a pioneer in this type of research.