LEAP 2013 Uppsala SE

Antihydrogen is now routinely produced at CERN by overlapping clouds of positrons and antiprotons. The mechanisms responsible for antihydrogen formation (radiative capture and the three-body reaction) are both dependent on the temperature of the positrons (T_e), though with a different weight. Here we present a simple model of the behaviour of the positron temperature based on the main processes involved during antihydrogen synthesis, namely: antiproton-positron collisions, positron heating due to plasma expansion and cooling via the emission of synchrotron radiation. Simulations of the time evolution of T_e have been performed for the relevant working conditions of the CERN-AD experiments (but in particular ATHENA and ASACUSA) by changing the positron densities and the initial antiproton kinetic energies. A preliminary analysis comparing the experimental antihydrogen formation rates to those calculated using the present model results is also presented.