Commissioning of a dual-phase xenon TPC at Nikhef
  A dual-phase xenon time-projection chamber was built at Nikhef in Amsterdam as a direct dark matter detection R&D facility. In this paper, the setup is presented and the first results from a calibration with a $^{22}$Na gamma-ray source are presented. The results show an average light yield of (5.6 $\pm$ 0.3) photoelectrons/keV (calculated to 122 keV and zero field) and an electron lifetime of (429 $\pm$ 26) $\mu$s. The best energy resolution $\sigma_E/E$ is (5.8 $\pm$ 0.2)% at an energy of 511 keV. This was achieved using a combination of the scintillation and the ionization signals. A photomultiplier tube gain calibration technique, based on the electroluminescence signals occurring from isolated electrons, is presented and its advantages and limitations are discussed. 
E. Hogenbirk, J. Aalbers, M. Bader, P.A. Breur, A. Brown, M.P.   Decowski, C. Tunnell, R. Walet, A.P. Colijn
physics.ins-det hep-ex