Professor Jocelyn Monroe

Abstract:

The Dark Matter Time Projection Chamber (DMTPC) collaboration has developed a direction-sensitive detector for tracking low-energy nuclear recoils. A large-scale version of this type of detector has potential to make a definitive directional detection of dark matter, as well as interesting possibilities for the first detection of ⁴⁰K geo-neutrinos. © 2012 Elsevier B.V.

Abstract:

The DMTPC directional dark matter detection experiment is a low-pressure CF4 gas time projection chamber, instrumented with charge and scintillation photon readout. This detector design strategy emphasizes reconstruction of WIMPinduced nuclear recoil tracks, in order to determine the direction of incident dark matter particles. Directional detection has the potential to make the definitive observation of dark matter using the unique angular signature of the dark matter wind, which is distinct from all known backgrounds. This talk will review the experimental technique and current status of DMTPC. © 2012 American Institute of Physics.

Abstract:

The SciBooNE and MiniBooNE collaborations report the results of a ν μ disappearance search in the Δm2 region of 0.5-40eV2. The neutrino rate as measured by the SciBooNE tracking detectors is used to constrain the rate at the MiniBooNE Cherenkov detector in the first joint analysis of data from both collaborations. Two separate analyses of the combined data samples set 90% confidence level (CL) limits on ν μ disappearance in the 0.5-40eV2 Δm2 region, with an improvement over previous experimental constraints between 10 and 30eV2. © 2012 American Physical Society.

Abstract:

The MiniCLEAN dark matter direct detection experiment is a single-phase liquid argon detector, instrumented with photomultiplier tubes to observe scintillation light from a 150kg fiducial mass. This detector design strategy emphasizes scalability to target masses of order 10 tons or more. The projected light yield is 6 photo-electrons per keV, which allows pulse shape discrimination to separate the electron background from a WIMP-induced nuclear recoil signal. MiniCLEAN is also designed for a liquid neon target which, in the event of a positive signal in argon, will enable an independent verification of backgrounds and provide a unique test of the expected A² dependence of the WIMP interaction rate. This talk will review the experimental technique and current status of MiniCLEAN.

Abstract:

The Dark Matter Time Projection Chamber (DMTPC) collaboration is developing a low-pressure gas TPC for detecting WIMP-nucleon interactions. DMTPC detectors use optical readout with CCD cameras to search for the daily modulation of the directional signal of the dark matter wind. An analysis of several charge readout channels has been developed to obtain additional information about ionization events in the detector. In order to reach sensitivities required for the WIMP detection, the detector needs to minimize backgrounds from electron recoils. This article shows that by using the readout of charge signals in addition to CCD readout, a preliminary statistics-limited 90% C.L. upper limit on the γ and e^- rejection factor of 5.6 × 10^-6 is obtained for energies between 40 keVee and 200 keVee.