A Proposal to Operate the COUPP-60 Bubble Chamber at SNOLAB

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Research Project

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Bubble chambers are promising devices for the detection of WIMP dark matter, due to their easy scalability to large target masses and insensitivity to background gamma and beta radiation. The COUPP collaboration has constructed small chambers which have achieved competitive sensitivity for spin-dependent WIMP-nucleon scattering. A new chamber, COUPP-60, containing 60-kg of CF3I target liquid, has been built and is being commissioned at Fermilab. We propose to move this detector to SNOLAB after completing tests in a shallow underground site at Fermilab. At SNOLAB, we expect the sensitivity of the experiment to be determined by the level of alpha-emitting contamination in the target liquid. If we achieve state-of-the-art levels of alpha emitting contamination, we will improve current sensitivity by approximately four orders of magnitude beyond our published limits, to the region of 10^-4 pb for a 30 GeV WIMP interaction by spin-dependent couplings to the proton. This will allow a first exploration of the phase space favored by supersymmetric models in this regime.


Lead author: Juan Collar

Corresponding author: Juan Collar

Collaboration: COUPP