We have used the Shenguang Ⅱ laser in third harmonic (351 nm) to investigate the emission of L-shell radiation in the 3.3-4.4 keV range generated using thin foils of Sn coated onto a parylene substrate with irradiation of order 1015 W cm-2 and nanosecond pulse duration.In our experiment,we have concentrated on assessing the emission on the non-laser irradiated side as this allows an experimental geometry relevant to experiments on photo-ionised plasmas where a secondary target must be placed close to the source,to achieve x-ray fluxes appropriate to astrophysical objects.Overall L-shell conversion efficiencies are estimated to be of order 1％,with little dependence on Sn thickness between 400 and 800 nm.