A TNSA based platform for deuterium and tritium beams to study nuclear reactions between light nuclei

Thesis (Ph. D.)--University of Rochester. Departments of Chemistry, and Physics and Astronomy, 2021.
A controllable tritium beam provides an invaluable tool for the study of nuclear reactions involving neutron rich nuclei such as 6He, 9 Li and 11Be. Other potential applications in the field of inertial confinement fusion (ICF) include independent measurements of the tritium-tritium (TT) reaction and triton-driven fast ignition. However, the handling of diffusive, radioactive tritium is very challenging for accelerator facilities. On the other hand, target normal sheath acceleration (TNSA) can produce beams with isolated, miniature (500x500x25µm³) converter targets, requiring only micro Curies of activity. The focus of this project was the development of such a TNSA-based triton beam platform. The TNSA experiments were conducted at the two LLE laser facilities Multi Terawatt (MTW) and OMEGA-EP (Extended Performance). While the aspects of TNSA were studied on the low energy (~20J), high repetition (20 min shot cycle) MTW system, the nuclear experiments were conducted on the high energy (1.25kJ) OMEGA-EP system. A central part of this work was the design and fabrication of deuterium- and tritiumdoped targets to be used in TNSA experiments. The loading procedures were continuously optimized using results from the MTW platform. From these experiments, it was found that exposure of the titanium target to high pressure (~950 Torr), high temperature (400°C) molecular deuterium maximizes the total deuterium yield of the targets. The laser energy has a strong impact on both the total deuterium yield and spectrum, with the higher laser energies accelerating more deuterons to higher energies. A major experimental result of this work was the manipulation of the deuteron spectra - by increasing the laser energy - from an exponential to an exponentially modified Gaussian shape, with maximum mean beam energies of 0.5 ± 0.2 MeV. A custom ion dynamics code was developed as part of this project to interpret this result. On OMEGA-EP, an exponential spectrum with mean 2.3 ± 2.3 MeV and