We report the first analysis of background data from DM-Ice17, a direct-detection dark matter experiment consisting of 17 kg of NaI(Tl) target material. It was codeployed with IceCube 2457 m deep in the South Pole glacial ice in December 2010 and is
the first such detector operating in the Southern Hemisphere. The background rate in the 6.5 - 8.0 keVee region is measured to be 7.9 +/- 0.4 counts/day/keV/kg. This is consistent with the expected background from the detector assemblies with negligible contributions from the surrounding ice. The successful deployment and operation of DM-Ice17 establishes the South Pole ice as a viable location for future underground, low-background experiments in the Southern Hemisphere. The detector assembly and deployment are described here, as well as the analysis of the DM-Ice17 backgrounds based on data from the first two years of operation after commissioning, July 2011 - June 2013.
The Daya Bay experiment measures sin^2 2{theta}_13 using functionally identical antineutrino detectors located at distances of 300 to 2000 meters from the Daya Bay nuclear power complex. Each detector consists of three nested fluid volumes surrounded
by photomultiplier tubes. These volumes are coupled to overflow tanks on top of the detector to allow for thermal expansion of the liquid. Antineutrinos are detected through the inverse beta decay reaction on the proton-rich scintillator target. A precise and continuous measurement of the detectors central target mass is achieved by monitoring the the fluid level in the overflow tanks with cameras and ultrasonic and capacitive sensors. In addition, the monitoring system records detector temperature and levelness at multiple positions. This monitoring information allows the precise determination of the detectors effective number of target protons during data taking. We present the design, calibration, installation and in-situ tests of the Daya Bay real-time antineutrino detector monitoring sensors and readout electronics.
This paper describes in detail the acrylic target vessels used to encapsulate the target and gamma catcher regions in the Daya Bay experiments first pair of antineutrino detectors. We give an overview of the design, fabrication, shipping, and install
ation of the acrylic target vessels and their liquid overflow tanks. The acrylic quality assurance program and vessel characterization, which measures all geometric, optical, and material properties relevant to { u}e detection at Daya Bay are summarized. This paper is the technical reference for the Daya Bay acrylic vessels and can provide guidance in the design and use of acrylic components in future neutrino or dark matter experiments.
Astrophysical observations and cosmological data have led to the conclusion that nearly one quarter of the Universe consists of dark matter. Under certain assumptions, an observable signature of dark matter is the annual modulation of the rate of dar
k matter-nucleon interactions taking place in an Earth-bound experiment. To search for this effect, we introduce the concept for a new dark matter experiment using NaI scintillation detectors deployed deep in the South Pole ice. This experiment complements dark matter search efforts in the Northern Hemisphere and will investigate the observed annual modulation in the DAMA/LIBRA and DAMA/NaI experiments. The unique location will permit the study of background effects correlated with seasonal variations and the surrounding environment. This paper describes the experimental concept and explores the sensitivity of a 250 kg NaI experiment at the South Pole.
