Characterization of fusion burn time in exploding deuterium cluster plasmas

Exploiting the energetic interaction of intense femtosecond laser pulses wi th deuterium clusters, it is possible to create conditions in which nuclear fusion results from explosions of these clusters. We have conducted high-r esolution neutron time-of-flight spectroscopy on these plasmas and show tha t they yield fast bursts of nearly monochromatic fusion neutrons with tempo ral duration as short as a few hundred picoseconds. Such a short, nearly po intlike source now opens up the unique possibility of using these bright ne utron pulses, either as a pump or a probe, to conduct ultrafast studies wit h neutrons.