Time-resolved Rayleigh scattering measurements of methane clusters for laser-cluster fusion experiments

We present a time-resolved analysis of Rayleigh scattering measurements to determine the average size of methane clusters and find the optimum timing for laser-cluster fusion experiments. We measure Rayleigh scattering and determine the average size of methane clusters varying the backing pressure (P-0) from 11 bar to 69 bar. Regarding the onset of clustering, we estimate that the average size of methane clusters at the onset of clustering is N(c0)20 at 11 bar. According to our measurements, the average cluster radius r follows the power law of r proportional to P-0(1.86). Our ion time-of-flight measurements indicate that we have produced energetic deuterium ions with kT = 52 +/- 2 keV after laser-cluster interaction using CD4 gas at 50 bar. We find that this ion temperature agrees with the predicted temperature from CD4 clusters at 50 bar with r = 14 nm assuming the Coulomb explosion model.

Automated summary

Time-resolved analysis of Rayleigh scattering measurements was used to determine the average size of methane clusters and find the optimum timing for laser-cluster fusion experiments. The study also revealed the production of energetic deuterium ions after laser-cluster interaction, which was consistent with the predicted temperature from CD4 clusters.