Grazing-incidence pumped Ni-like Sn X-ray laser media at 11.9 nm (4d-4p, J = 0-1) is modelled using 1 1/2d code EHYBRID and a post-processor code. The required atomic data are obtained using the Cowan code. In this study the pre-formed plasma is pumped on longitudinal direction with a grazing angle. Detailed simulations were performed to optimize the driving laser configurations. Relatively high gain is produced for the Ni-like Sn X-ray laser at 11.9 nm with long pre-pulse and short main pulse drive energy of only 100 mJ on 4 mm slab targets. Using low intensity pre-pulse prior to long pulse decreases the electron density gradient. X-ray resonance lines between 13 and 25 A emitted from tin plasma have been simulated using post-processor coupled with EHYBRID. The ratio of these resonance lines can be used to measure electron temperature of the laser produced Sn plasma. (c) 2007 Elsevier B.V. All rights reserved.