Bulletin of the American Physical Society
APS April Meeting 2011
Volume 56, Number 4
Saturday–Tuesday, April 30–May 3 2011; Anaheim, California
Session H8: Dark Matter Experiments and Neutron Shielding |
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Sponsoring Units: DPF DAP GPMFC Chair: Ed Blucher, University of Chicago Room: Grand F |
Sunday, May 1, 2011 10:45AM - 10:57AM |
H8.00001: CoGeNT-4: Prospects for an expanded search for light-mass WIMPS John Orrell, Craig Aalseth, Juan Collar, Tony Day, Nicole Fields, Erin Fuller, Todd Hossbach, Marty Keillor, Dick Kouzes, Cory Overman, Brent Vandevender The CoGeNT experiment located at the Soudan Underground Laboratory has reported an excess of events below an electron scattering equivalent of 1 keV. This result may be interpreted alternatively as either an unidentified background contribution or a signature of light-mass (5-10 GeV/c2) weakly interacting massive particle (WIMP) dark matter. The initial CoGeNT results were produced using a single 440 gram high-purity germanium radiation detector operated at liquid nitrogen temperature. To further test these unexpected results, an expanded CoGeNT-4 experimental design is under development. The shield design concept is presented and the science impact of a four-detector experiment is explored. Of particular interest is the sensitivity to a hypothesis for light-mass WIMP dark matter particles in the 5-10 GeV/c2 mass range that could potentially explain the initial CoGeNT results as well as the results of the DAMA/LIBRA experiment. [Preview Abstract] |
Sunday, May 1, 2011 10:57AM - 11:09AM |
H8.00002: Background Rejection in SuperCDMS iZIP Detectors Matt Pyle To achieve the background rejection level required for future ton scale dark matter searches with germanium, the SuperCDMS collaboration has demonstrated an advanced interleaved charge and phonon detector. Fiducial volume 3D reconstruction can be accomplished using either phonon pulse shape information or charge collection distributions on the four separately instrumented electrodes. Furthermore, our newest detectors display nuclear versus electronic recoil discrimination in phonon pulse shape alone, in addition to our traditional charge yield measurement. We will report the latest results at the meeting. [Preview Abstract] |
Sunday, May 1, 2011 11:09AM - 11:21AM |
H8.00003: The MiniCLEAN Single-Phase Noble Liquid Dark Matter Experiment Michael Ronquest MiniCLEAN is a single-phase WIMP dark matter experiment which observes scintillation light from a 150kg fiducial mass liquid argon target. This detector design strategy emphasizes scalability to target masses of order 10 tons or more. The liquid noble target is observed by a sphere of 92 photomultiplier tubes; the projected light yield is $>$5 photo-electrons per keV. The high light yield 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 will provide a unique test of the expected A squared dependence of the WIMP interaction rate. This talk will review the experimental technique and current status of MiniCLEAN. [Preview Abstract] |
Sunday, May 1, 2011 11:21AM - 11:33AM |
H8.00004: The DarkSide-10 Prototype Dark Matter Detector Ben Loer The DarkSide collaboration will search for evidence of interactions of Weakly Interacting Massive Particles (WIMPs) with normal matter using a two-phase argon Time Projection Chamber (TPC). The TPC measures both the scintillation and ionization of interactions in the detector, providing precise measurement of the interaction position and two means to discriminate minimum ionizing particles from potential WIMP signals: the time profile of the primary scintillation pulse and the ratio of scintillation to ionization. We have constructed DarkSide-10, a 10kg argon TPC, as a prototype for full-scale physics detectors. I will describe the key features of this detector and present results from recent data collection campaigns at Princeton University. [Preview Abstract] |
Sunday, May 1, 2011 11:33AM - 11:45AM |
H8.00005: Liquid-nitrogen cryogenic system for noble liquid detectors Emily Lebsack The next generation of noble liquid dark-matter detectors will require a powerful, stable, and adjustable cryogenic cooling system that will not introduce backgrounds into the detector. I will discuss the design and operation of a novel liquid-nitrogen based heat exchanger capable of delivering a widely varying degree of cooling power and maintaining a range of stable temperatures. I will present measurements from our successful integration of this cooling system with our liquid argon time-projection-chamber, Darkside-10. [Preview Abstract] |
Sunday, May 1, 2011 11:45AM - 11:57AM |
H8.00006: Active Neutron Shielding R\&D for Dark Matter Searches Shawn Henderson, Jocelyn Monroe, Peter Fisher Neutrons are a dangerous background to direct dark matter detection searches because they can mimic exactly the signal signature. For this reason, it is desirable to measure the neutron flux directly at underground sites where dark matter experiments are active. We have developed a liquid scintillator-based neutron detector for this purpose, which is currently underground and taking data at the Waste Isolation Pilot Plant (WIPP) in NM. Before being commissioned underground, the response of this detector to neutrons with kinetic energies from 50 MeV to 800 MeV was determined in a beam test at the Los Alamos Neutron Science Center (LANSCE) in NM. The goal of this R\&D is to (i) demonstrate the feasibility of a large scale active and passive neutron shield for dark matter searches and (ii) to measure the neutron energy spectrum underground at WIPP above 50 MeV neutron kinetic energies. [Preview Abstract] |
Sunday, May 1, 2011 11:57AM - 12:09PM |
H8.00007: Measurements of Neutron Shielding by Water and Concrete from 100 - 800 MeV Kimberly Palladino, Jocelyn Monroe, Shawn Henderson Nuclear recoils caused by neutron scatters may feign WIMP signals in direct dark matter detectors. Cosmic muon spallation is a considerable source of neutrons extending to GeV energies. Low background experiments operate below ground to reduce the incident muon flux, and commonly employ water or concrete shielding to absorb neutrons created in the surrounding cavern material. Here we present the measurements of the shielding efficiency of these materials for incident neutrons of 100-800 MeV taken at the Los Alamos Neutron Science Center, the first such measurements in this energy range. [Preview Abstract] |
Sunday, May 1, 2011 12:09PM - 12:21PM |
H8.00008: Measuring External Sources of Background at Homestake for DUSEL Experiments Dongming Mei, Keenan Thomas, Chao Zhang, Fred Gray, Jaret Heise, Dan Durben Fluxes of external radioactivity are known to vary in time and could mimic the experimental signature for dark matter and neutrinoless double-beta decay searches. Measuring and monitoring external sources of radioactivity at experimental sites is the key to success in low-energy neutrino and dark matter (WIMP search) experiments. Data from the background characterization program will be of use to both the DUSEL facility design as well as experiments. Researchers can use the information to understand shielding or other mitigation requirements as well as in the interpretation of their experimental results. This work aims to continue and expand our current efforts to measure and monitor external sources of background continuously for experiments planned for the Sanford Laboratory as well as those proposed for DUSEL. [Preview Abstract] |
Sunday, May 1, 2011 12:21PM - 12:33PM |
H8.00009: ABSTRACT WITHDRAWN |
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