Simulation studies of neutron shielding, calibration and veto systems for gaseous dark matter detectors

We present and discuss the results of simulations of unshielded and shielded neutron background in underground gaseous nuclear recoil detectors for dark matter searches. Also included are measurements of the U and Th content of the rock using an unshielded Ge detector, first studies of neutron veto systems to reject neutron background from detector components, and signal discrimination by varying gas mixtures.