Grant: Subatomic Physics Envelope - Project

The origin of the dark matter in our universe is currently one of the most important questions in particle astrophysics. Our research is targeting a liquid argon detector for dark matter particles with a sensitivity to the WIMP-nucleon cross-section of 10^{-46} cm^2, which is a factor of 500 more sensitive than current experimental limits, and is a factor of ten more sensitive than proposed dark matter searches. One of the largest challenges in dark matter particle searches is the reduction of background events that could mimic a dark matter particle interaction. We have constructed a 7 kg liquid argon scintillation detector (DEAP-1) and used it to demonstrate a very high level of background discrimination at low energies. We are currently furthering low-background studies underground with the prototype detector at SNOLAB. We have used NSERC funds to continue the design and engineering of the large liquid argon detector. The conceptual detector design is essentially complete and includes a large spherical acrylic vessel viewed by 266 photomultiplier tubes (PMTs) through acrylic light guides. The vessel, light guides and PMTs are contained in a spherical stainless steel shell, and the entire detector is submerged in an 8 meter diameter shielding tank to remove external neutrons and gamma rays. This proposal will allow us to complete the engineering design of the detector, and to begin construction at SNOLAB. We are currently supporting approximately 20 highly-qualified personnel (HQP) per year (including post-doctoral researchers, research associates, students, and technical and engineering personnel) from NSERC funds. In addition to fostering research collaborations with international partners, this proposal will lead to further training of HPQ in Canada, with a request of support for 27 researchers.