  We demonstrate a Wiley-McClaren Time of Flight Mass Spectrometer modified to
allow direct extraction of ions from a laser-induced plasma. Unlike many other
methods that utilize mass spectrometry to investigate laser-induced plasmas, no
collisional cooling or further ionization of the plasma is required prior to
acceleration, allowing measurements of the plasma ion composition to be
obtained directly. Furthermore, we show using the laser ablation of gadolinium
as an example that we are able to obtain the translational energy distribution
of the plasma directly and infer information about the relative composition of
ions within different regions of the plasma plume. The approach is then applied
to laser ablation of a uranium sample as a step toward probing the chemistry
under conditions relevant to a nuclear fireball for nuclear forensics
applications.
