Experimental study of fusion neutron and proton yields produced by petawatt-laser-irradiated D2-³He or CD4-³He clustering gases.

ABSTRACT

We report on experiments in which the Texas Petawatt laser irradiated a mixture of deuterium or deuterated methane clusters and helium-3 gas, generating three types of nuclear fusion reactions D(d,^{3}He)n, D(d,t)p, and ^{3}He(d,p)^{4}He. We measured the yields of fusion neutrons and protons from these reactions and found them to agree with yields based on a simple cylindrical plasma model using known cross sections and measured plasma parameters. Within our measurement errors, the fusion products were isotropically distributed. Plasma temperatures, important for the cross sections, were determined by two independent methods: (1) deuterium ion time of flight and (2) utilizing the ratio of neutron yield to proton yield from D(d,^{3}He)n and ^{3}He(d,p)^{4}He reactions, respectively. This experiment produced the highest ion temperature ever achieved with laser-irradiated deuterium clusters.