Wednesday 3 September 2008 Speaker: Pawel Majewski (RAL) Title: Nuclear Recoil Measurements in Dark Matter Research Abstract: Direct searches for dark matter aim to detect the elastic nuclear recoil of an incident Weakly Interacting Massive Particle (WIMP) off a target nucleus. Energy scale calibration is performed by exposing the detector to radiation from a gamma-ray emitting radioisotope. Unlike for WIMPs and neutrons detectable energy from gamma-rays is a result of collisions with target electrons rather than nuclei, hence due to higher excitation density from the latter the scintillation yield is expected to be different. I will present results of the scintillation yield measurements for nuclear recoils in materials relevant to dark matter searches focusing on liquid xenon, NaI and CaWO4.