This paper introduces a new stochastic process in which the iterates o
f a dynamical system evolving in discrete time coincide with the event
s of a Poisson process. The autocovariance function of the stochastic
process is studied and a necessary and sufficient condition for it to
vanish is deduced. It is shown that the mean function of this process
comprises a continuous-time semidynamical system if the underlying dyn
amical map is linear. The flow of probability density functions genera
ted by the stochastic process is analysed in detail, and the relations
hip between the flow and the solutions of the linear Boltzmann equatio
n is investigated. It is shown that the flow is a semigroup if and onl
y if the point process defining the stochastic process is Poisson, the
reby providing a new characterization of the Poisson process.