Ionization of Atomic Hydrogen and Helium by Low Energy Antiprotons

Lead Research Organisation: Queen's University of Belfast
Department Name: Sch of Mathematics and Physics


Experimental studies of collision processes, in which fundamental charged particles ionize simple atoms and molecules, provide the data necessary for our understanding of the many-body interaction and the development a theoretical description of this fundamental yet unsolved problem in collision dynamics. The ionization process plays an important role in astrophysical and technological plasmas and in the dissociation of molecules in the Earth's atmosphere. A comparison of single and multiple ionization of simple atomic and molecular targets by equi-velocity protons, electrons and their corresponding antiproton and positron antiparticles makes it possible to determine the effects of projectile mass and charge.The separation of 'pure' ionization from electron capture or transfer ionization processes can be studied in the special case of antiprotons colliding with light atoms. The absence of electron transfer is a significant simplification and the mass of the projectile enables straight-line trajectories models to be used.


10 25 50
publication icon
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

publication icon
Knudsen H (2008) Ionization of helium and argon by very slow antiproton impact. in Physical review letters

Description Univ of Swansea 
Organisation Swansea University
Country United Kingdom 
Sector Academic/University 
PI Contribution We worked together with Professor Charlton at CERN on the experimental project on antiproton collisions.
Collaborator Contribution Professor Charlton made a positive contribution to both the operation of the experiment and the discussions of the physics involved
Impact Deatils of all publications have been listed.
Start Year 2006
Description University of Arhus 
Organisation Aarhus University
Country Denmark 
Sector Academic/University 
Start Year 2007
Description University of Tokyo 
Organisation University of Tokyo
Country Japan 
Sector Academic/University 
Start Year 2007