School Seminar Program

Exotic atom scattering: Building a positronium beam

Date & time

Thu 28 Sep 2017, 3pm





Members of RSPE welcome


Dr Josh Machacek
Plasma Research Laboratory

Positronium is composed of a positron and an electron forming a hydrogenic atom. This exotic atom can be used to test our understanding of a range of scattering processes. A typical positronium beam has low intensity due to the difficulties involved in producing a positron beam thereby limiting the experimental tests which are feasible.

The development of buffer gas traps, or Surko traps, has allowed for the accumulation and control of positrons. A large number of positrons can be accumulated and then used to produce positronium via charge exchange with an atom or molecule. The goal is to produce an intense positronium beam.

Intense positronium beams can be used to explore how positronium fragments molecules and search for attachment channels. Ultimately, these beams open up a new chapter in atomic and molecular physics of using positronium.

Dr Josh Machacek received his PhD from ANU. He worked as a post-doc at the Jet Propulsion Lab (California Institute of Technology) in the US before returning to the ANU. In 2016, he was awarded a DECRA fellowship. Josh’s research focuses on positron and positronium interactions with atoms and molecules in an effort understand damage, or fragmentation, of complex molecules.

Updated:  17 August 2017/ Responsible Officer:  Head of Laser Physics/ Page Contact:  Physics Webmaster