The neutron transport with general boundary conditions

In this Note, the one-dimensional transport operator with general boundary conditions is studied. We show the generation of a strongly continuous semi group by this operator. We give simple and practical conditions on the boun dary operator to ensure the positivity and the irreducibility of generated semigroup. We calculate explicitly the essential type of the generated semi group and we show its convergence to rank one projection in operators norm topology. (C) Academie des Sciences/Elsevier, Paris.