Grant: Subatomic Physics Envelope - Project

We have strong indication that more than 80% of the matter in the Universe consists of a new type of elementary particle, likely fairly massive and weakly interacting with ordinary matter (Weakly Interacting Massive Particle, WIMP). CDMS (Cryogenic Dark Matter Search) aims at detecting the very rare interactions of WIMPs in terrestrial detectors for the first time in history. CDMS has been operating for more than a decade now, being the most sensitive experiment in the field for most of the time. So far no signal has been observed. The successor SuperCDMS is improving its sensitivity with even better detectors and a larger active mass. At Queen's University we have installed a detector testing facility which will allow us to qualify the new detectors before they enter the experimental setup in the Soudan underground laboratory in Minnesota. To go beyond the sensitivity which can be achieved with the active mass being installed over the next year (~15 kg), SuperCDMS plans to build a new experimental setup for ~150 kg of detectors at SNOLAB which is better shielded from cosmic radiation than Soudan. To take full advantage of the new setup, the requirements for the discrimination of background events are much more stringent. This discrimination cannot be tested above ground due to the cosmic radiation. Therefore we propose to install a testing facility underground at SNOLAB for these specific measurements, which are essential for the success of SuperCDMS at SNOLAB. In this proposal we ask for support for highly qualified personnel to install the new facility at SNOLAB and for the operation of both testing facilities (Queen's, SNOLAB). Postdoctoral Fellows and graduate students will be instrumental in carrying out the proposed research, with help from technical personnel. All involved parties will be trained in installing and operating the vacuum and cryogenic systems; PDFs and students will learn how to operate the complex cryogenic detectors and analyze the data. Participating in the operation of SuperCDMS at Soudan, in collaboration meetings and in national and international conferences will be an invaluable addition to the training of the scientific personnel and help represent Canada's excellence in research.