Grant: Discovery Grants Program - Individual

ANTIHYDROGEN: Our international ATRAP collaboration is focused on the production, trapping, laser cooling and study of antihydrogen atoms. The objectives of our collaboration include high precision measurements of atomic energy levels interval in this first antimatter atom. These measurements will be compared to those in hydrogen and provide a sensitive test of fundamental symmetries on nature. Since antimatter does not exist in our world it must be produce from antiprotons (produced with CERN accelerators) and positrons emitted in radioactive decay of unstable sodium nucleii. These are captured and cooled to near absolute zero temperature such that antihydrogen atoms produced can be captured and studied.FIRST NUCLEAR REACTOR BASED POSITRON ACCUMULATOR: Existing systems for cold trapped positrons are based on radioactive isotopes with limited strength and availability and require replacement every few years when the source decays. Our new system will accumulate positrons produced in a metal foil positioned near the core of the McMaster Nuclear Reactor. The McMaster Intense Positron Beam Facility will provide an intense continuous beam of low energy positrons at a much higher rate than radioactive isotopes. This will be the first system optimized to capture and cool the positrons from a reactor. This bench mark system will play a leading role in the next generation of low energy positron traps for the existing and future reactor based positron beams.ATOMIC PHYSICS WITH POSITRONIC ATOMS: Physics objectives include precise measurements of atomic energy level intervals in positronium, an electron bound to a positron. Better measurements of the structure of this atom are required with improved precision to test the most recent QED theory. We are also pursuing the production and study of a new type of atom, a positron bound in a highly excited state to a hydrogen-minus ion. Measurements of the positron excitation energies will provide a sensitive probe of the hydrogen-minus structure.