Benchmark Experiments for Low Energy Positron Scattering from Helium
- Chief Supervisor
- Dr. James Sullivan
- Supervisors
- Prof. Stephen Buckman
- A/Prof. Michael Brunger
- Prof. Peter Teubner
- Centre Nodes
- ANU, Flinders, Murdoch
- Collaborators
- Drake University (USA)
The Helium atom is the simplest experimental system that is readily accessible for atomic collision experiments. In electron physics it has served as the benchmark for both experiment and theory for many decades, such that the level of agreement between experiment and theory for most electron-driven processes in helium is now exceptionally good. The importance of such fundamental benchmark systems is twofold. First, they provide a guide for testing both new experimental and theoretical techniques. Second, they give confidence that successful theoretical approaches can then be extended to more complex systems were experiments may not be possible.
In contrast, the only cross section for positron-helium scattering that is presently known to a high level of precision, is the grand total scattering cross section. The aim of this project is to provide the first comprehensive measurements of discrete, absolute, positron–helium collision processes including, total scattering, differential elastic scattering, positronium formation and integral excitation cross sections for discrete excited levels (n=2 and 3). There are no such measurements presently available for this relatively simple atomic system, and the experimental program, to be conducted at the Positron Beamline Facility at the ANU, will be closely allied with a similar theoretical program within the Centre, at Murdoch and Drake Universities.
The successful candidate will have an aptitude for experimental physics, a capacity to learn how to operate complex experimental apparatus, an ability to work in a team with other students and scientific staff, and an interest in frontier scientific measurements. She/He will develop many general experimental and scientific skills including handling charged anti–matter and matter beams, precision instrumentation, high vacuum technology, computer interfacing of experimental control using LabView software, data analysis and interpretation, manuscript writing, scientific communication and general atomic and molecular spectroscopy.
