Antimatter in the Universe
Dr Mike Charlton
University of Wales, Swansea
The topic of antimatter will be introduced by recalling its prediction and discovery in the 1930’s, and a brief history of the subject will be given. Positrons have since found numerous applications in atomic and materials science, engineering and medicine, often based upon their annihilation with electrons, their matter equivalent particle. What makes this antiparticle useful as a probe will be discussed and a few examples described.
Recently, physicists working at CERN have learnt how to create atoms of antihydrogen under controlled conditions in vacuum and capture some of them in a magnetic minimum neutral atom trap. A few of these anti-atoms have been held for periods longer than 15 minutes. These experiments will be described, as well as the motivation for undertaking them. The latter will involve one of nature’s great conundrums: the absence of bulk antimatter in the current epoch of the Universe.
Mike Charlton studied at University College London (UCL), graduating with a 1st Class Honours BSc in 1978, before completing his PhD on the interactions of low energy positrons in gases in 1980. He stayed at UCL for postdoctoral work, being awarded a Science Research Council Postdoctoral Fellowship in 1982 followed by a Royal Society Research Fellowship in 1983. In 1991 he was promoted to Reader in Physics at UCL. In 1999, he moved to Swansea as Professor in Experimental Physics. He has been Chair of the Department of Physics, and the School of Physical Sciences, at Swansea. He has made many contributions to low energy positron physics, particularly in the areas of positronium formation, ionization and annihilation and in the development of low energy beams and related instrumentation. He began antihydrogen research in 1986, and this is now his main area of endeavour. He is currently an Engineering and Physical Sciences Research Council Senior Research Fellow. He is a Fellow of the Institute of Physics and of the Learned Society of Wales and is a co-recipient of the 2011 American Physical Society John Dawson Award for Excellence in Plasma Physics Research for contributions to antihydrogen trapping.