Temperature dependence of S(Q) for liquid 4He

High accuracy (typically +-0.4%) results for the total neutron scattering by liquid 4He have been obtained for Q = 2.04 A-1, the position of the principal peak of S(Q), at 27 temperatures in the range 1.04 <= T <= 4.23 K with particular emphasis on the region near Tsub(lambda). Less complete results have also been obtained for Q = 1.87 and 2.30 A-1. The principal peak is very clearly seen to sharpen and increase in height as one approaches Tsub(lambda) from either side. There is also a surprising discontinuity of 1.5% in peak height on crossing Tsub(lambda). Two recent predictions for the temperature variation of S(Q) for superfluid 4He are found to give good agreement with our new results. (orig.)