Reconstruction over a large rapidity interval of Λ, and K0S in the NA49 experiment

The NA49 experiment is able to measure the production of neutral strange baryons and mesons along with other hadronic species in Pb + Pb collisions at 158 GeV per nucleon. These strange particles are an important piece of evidence in the search for the quark-gluon plasma. They have been reconstructed from their charged decay products recorded in the experiment's time projection chambers. A new round of data production has been undertaken with improved software, allowing the reconstruction of neutral strange particles over a rapidity interval covering both sides of mid-rapidity. The procedures used to obtain this sample are outlined and a comparison of the phase space coverage with respect to previous measurements is made.