Ionization of Atomic Hydrogen by Low Energy Antiprotons

Lead Research Organisation: Swansea University
Department Name: College of Science


The cross section for electron removal or ionization of the simplest atom (hydrogen or its isotope deuterium), by antiprotons, is of currently of considerable interest. This is the simplest collision system for testing theory with only one active electron and, since the antiproton cannot capture an electron, the detection of a hydrogen ion in coincidence with an antiproton after the collision process is a signature of the ionization process. The antiproton hydrogen collision system is therefore an ideal system against which to test our theoretical understanding of the few-body Coulomb physics involved in ionization.Ionization is an important process in astrophysical and technological plasmas and in the dissociation of molecules in the Earth's atmosphere. Technological plasmas are increasingly used in industrial proceessing of materials, particularly to effect their surface properties and are widely used in the semiconductor industry. Energy from controlled plasma fusion of hydrogen isotopes presents us with the possibility of a 'clean' energy source to replace fossil fuels and to alleviate global warming resulting from carbon dioxide emissions from current generation power stations.Our understanding of the ionization mechanism in such a simple collision system should enable an important step forward in current theoretical models.


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Capra A (2016) Limit on the electric charge of antihydrogen in Hyperfine Interactions

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Indelicato P (2014) The Gbar project, or how does antimatter fall? in Hyperfine Interactions

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Jonsell S (2016) The role of antihydrogen formation in the radial transport of antiprotons in positron plasmas in Journal of Physics B: Atomic, Molecular and Optical Physics

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Knudsen H (2009) On the double ionization of helium by very slow antiproton impact in Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms

Description Double ionisation cross section of helium atoms by slow antiproton impact have been measured.
Exploitation Route The results obtained during this grant have been used to discern between many advanced theoretical calculations.
Sectors Other

Description Our findings have been used by many scientists to justify theoretical and experimental work in number of areas of basic physics. Organisations such as CERN and our institutions have used our work to promote their respective missions, and in the public understanding of science.
First Year Of Impact 2010
Sector Other
Impact Types Cultural

Description University of Arhus 
Organisation Aarhus University
Country Denmark 
Sector Academic/University 
Start Year 2009
Description University of Tokyo 
Organisation University of Tokyo
Country Japan 
Sector Academic/University 
Start Year 2009