  ArDM is a new-generation WIMP detector which will measure simultaneously
light and charge from scintillation and ionization of liquid argon. Our goal is
to construct, characterize and operate a 1 ton liquid argon underground
detector. The project relies on the possibility to extract the electrons
produced by ionization from the liquid into the gas phase of the detector, to
amplify and read out with Large Electron Multipliers detectors. Argon VUV
scintillation light has to be converted with wavelength shifters such as
TetraPhenyl Butadiene in order to be detected by photomultipliers with bialkali
photocathodes. We describe the status of the LEM based charge readout and light
readout system R&D and the first light readout tests with warm and cold argon
gas in the full size detector.
