Search for Dark Matter with Liquid Argon and Pulse Shape Discrimination: Results from DEAP-1 and Status of DEAP-3600

Abstract: In the last decade, Direct Dark Matter searches has become a very active research program, spawning dozens of projects world wide and leading to contradictory results. It is on this stage that the Dark matter Experiment with liquid Argon and Pulse shape discrimination (DEAP) is about to enter. With a 3600~kg liquid argon target and a 1000~kg fiducial mass, it is designed to run background free during 3 years, reaching an unprecedented sensitivity of 10$^{-46}$~cm$^2$ for a WIMP mass of 100 GeV. In order to achieve this impressive feat, the collaboration followed a two-pronged approach: a careful selection of every material entering the construction of the detector in order to suppress the backgrounds, and optimum use of the pulse shape discrimination (PSD) technique to separate the nuclear recoils from the electronic recoils. Using the experience acquired ffrom the 7~kg-prototype DEAP-1, a 3600~kg detector is being completed at SNOLAB (Sudbury, CANADA) and is expected to start taking data in mid-2014.