Date of Award
Master of Science in Applied Physics
Department of Engineering Physics
Larry W. Burggraf, PhD
Laser-Plasma interactions have strong potential as future neutron sources. Measuring the neutron rate is difficult due to several issues: the very short duration of the laser pulse and subsequent fusion events (on the order of a few picoseconds), the corresponding short duration of the neutron pulse, and the simultaneous emission of other ionizing particles such as protons and electrons. A system was designed to measure neutron emission by imposing a delay from the emission of other radiation by conversion of the neutrons into ortho-positronium (o-Ps), the triplet state of positronium. This lifetime extension enables more sensitive and selective detection of neutron pulses by time separation of the neutron component from other background signals that are correlated with laser-plasma interactions. Detection of o-Ps annihilation is accomplished with techniques developed for Positron Annihilation Lifetime Spectroscopy (PALS). This research will advance understanding of nuclear processes in laser-plasmas
DTIC Accession Number
McTaggart, Shawn T., "Neutron Pulse-Time Extension through Conversion to Positronium" (2021). Theses and Dissertations. 5060.