Bulletin of the American Physical Society
APS April Meeting 2013
Volume 58, Number 4
Saturday–Tuesday, April 13–16, 2013; Denver, Colorado
Session Q12: Neutrino and Dark Matter Instrumentation |
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Sponsoring Units: DPF DNP Room: Plaza Court 1 |
Monday, April 15, 2013 10:45AM - 10:57AM |
Q12.00001: Xenon Purification Research and Development for the LZ Dark Matter Experiment Katherin Pech The LZ Experiment is a next generation dark matter detector based on the current LUX detector design, with a 7-ton active volume. Although many research and development breakthroughs were achieved for the 350 kg LUX detector, the large volume scaling required for LZ presents a new set of design challenges that need to be overcome. Because the search for WIMP-like dark matter requires ultra low background experiments, the xenon target material in the LZ detector must meet purity specifications beyond what is commercially available. This challenge is two-fold. The xenon must contain extremely low amounts of electronegative impurities such as oxygen, which attenuate the charge signal. Additionally, it must also have very little of the inert isotope Kr-85, a beta-emitter that can obscure the dark matter signal in the detector volume. The purity requirements for the LUX experiment have been achieved, but the factor of 20 scaling in volume for LZ and increased demands for sensitivity mean that new research and development work must be done to increase our xenon purification capabilities. This talk will focus on the efforts being done at Case Western Reserve University to meet these strict purity requirements for the LZ Experiment. [Preview Abstract] |
Monday, April 15, 2013 10:57AM - 11:09AM |
Q12.00002: R\&D Isotope Separation with Large Thermal Gradients for Ultra-Low Background Experiments Angela Alanson Chiller, Christopher Chiller, Benjamin Jasinski, Nathan Snyder, Dongming Mei Seeking an alternative method to obtain enriched 76Ge and 73Ge for planned neutrinoless double-beta decay and dark matter experiments, a cryogenic distillation column is developed in our university laboratory for germane gas. Prior to experimenting with germane gas, which requires significant safety measures in place, the distillation column was tested with CO2. The preliminary analysis shows that 45CO2 was separated and enriched within two hours at room temperature. Exploiting the isotopic gradient within the two-meter length and removing preferentially from top and bottom points, 44CO2, 45CO2, and 46CO2 were bottled for further analysis. Methods of preferential condensation and vaporization used for depletion and enrichment of bottled gases show equal viability for purification and isotope enrichment with CO2 as well as gases with phase changes within the equipment specifications. Potential for purification and isotope enrichment/depletion of gases such as argon and xenon are investigated. [Preview Abstract] |
Monday, April 15, 2013 11:09AM - 11:21AM |
Q12.00003: Development and Testing of a High Voltage Feedthrough for Noble Liquid TPCs Artin Teymourian, Yixiong Meng, Emilija Pantic, Hanguo Wang Noble liquid Time Projection Chambers (TPCs) are used in many experiments for the detection of WIMPs and neutrinos. In a TPC, an incoming particle deposits energy in the target material (liquid argon or liquid xenon) and creates scintillation light, which is detected by photodetectors. The deposited energy also ionizes some of the atoms of the target material, and the ionized electrons are drifted toward a gas phase or charge readout wires as a secondary signal. The TPCs require electric fields on the order of 1 kV/cm in order to drift the ionized electrons. For this reason, larger TPCs will require higher voltages to maintain the same electric field. The voltage required for the electric field is provided by a high voltage feedthrough. In this talk, I will present the development and testing of a high voltage feedthrough at UCLA capable of exceeding 100 kV in liquid argon and liquid xenon TPCs. This feedthrough design will be used in the future XENON1Ton, DarkSide50, and LBNE detectors. The feedthrough must withstand the high voltage and should be vacuum tight. In the case of dark matter detectors, the feedthrough must also be constructed with materials that contain ultra-low intrinsic radioactivity. [Preview Abstract] |
Monday, April 15, 2013 11:21AM - 11:33AM |
Q12.00004: Novel Wavelength Shifting Collection Systems for Vacuum Ultraviolet Scintillation Photons in in Noble Gas Detectors Victor Gehman Detection of vacuum ultraviolet (VUV) photons presents a challenge because this band of the electromagnetic spectrum has a short enough wavelength to scatter off of most (though not all) materials, but is not energetic enough to penetrate into the bulk of a detector (so cannot be treated calorimetrically like x rays or $\gamma$ rays). This is exactly the band in which noble gasses (which make excellent media for radiation detectors) scintillate. VUV photon detection usually involves shifting them to visible wavelengths with a fluorescent molecule deposited on an optically clear surface viewed by a photosensor. Such techniques, while comparatively efficient and simple to fabricate, have high cost and complexity per unit coverage area making them prohibitively expensive and complicated to scale up to the very large sizes necessary for the next generation of neutrino, dark matter, and other rare event search experiments. We present several lines of inquiry attempting to address this problem, focusing on solutions that are directly applicable to a variety of current or next generation noble gas detectors. This line of R\&D is a potentially fruitful avenue capable of furthering the goals of many experiments with a broad portfolio of fundamental and applied research. [Preview Abstract] |
Monday, April 15, 2013 11:33AM - 11:45AM |
Q12.00005: Gain, Time and Spatial Resolution Measurements for 8"$\times$8" MCP-based Photo-Detectors Alexander Vostrikov Microchannel plates (MCP) are capable of picosecond-level time resolution and micron-level spatial resolution. Thin planar glass-body detectors based on 8"$\times$8" MCPs as the gain stage are being developed by the Large-Area Picosecond Photo-Detector Collaboration (LAPPD). In this detector photons hitting a photo-cathode produce photo-electrons, which are accelerated by high voltage and produce an avalanche of secondary electrons in the pores of a pair of MCPs. The avalanche is collected by a 30-strip anode, read out at both ends with a fully integrated 60-channel electronics system based on the PSEC4 ASIC that connects directly to the anode striplines. An ALD-based high voltage distribution design does not require penetrations of pins through the glass package. The modular design allows covering large areas while keeping the number of electronics channels low. A complete detector system close to the final detector design has been built to characterize MCPs. Gain of MCPs up to $2\cdot10^{7}$, single photon time-of-flight resolution of $\sim$60 psec, differential time resolution of $\sim$6 psec, and spatial resolution better than 1 mm in both longitudinal and transverse directions have been measured. [Preview Abstract] |
Monday, April 15, 2013 11:45AM - 11:57AM |
Q12.00006: Using Fast Photosensors in Water Cherenkov Neutrino Detectors Tian Xin The next generation of neutrino experiments will require massive and/or high resolution detectors to reach the sensitivity needed to measure CP violation in the lepton sector and the neutrino mass hierarchy. The Large-Area Picosecond Photo Detector (LAPPD) Collaboration is developing new methods to fabricate 8in-square thin planar micro channel plate photosensors, which have shown to have excellent spatial and timing resolution. By using these devices in Water Cherenkov detector, people could significantly improve the background rejection and the vertex reconstruction. We present preliminary results on the reconstruction capabilities for single particles in Water Cherenkov detectors. [Preview Abstract] |
Monday, April 15, 2013 11:57AM - 12:09PM |
Q12.00007: Performance of Water-based Liquid Scintillator Dmitriy Beznosko Water-based detectors can only see the Cherenkov light from the fast moving charged particles, thus missing all the particles below the Cherenkov threshold. Detecting these below-threshold particles is important for various applications like the mobile detectors for the nuclear reactor monitoring, the search of the proton decay, and reconstruction of the neutrino energy and the reaction type by observing the vertex activity for both long and short baseline experiments. This detection can be achieved by using the Water-based Liquid Scintillator (WbLS), currently under development. It is based on the idea of dissolving the organic scintillator in water using special surfactants. This new material strives to achieve the novel detection techniques by combining the Cherenkov rings and scintillation light, as well as the total cost reduction compared to pure liquid scintillator (LS). We will present light yield measurements for the proton beam energies of 210MeV, 475MeV and 2000MeV for water, two different WbLS formulations (1\% and 4\%) and pure LS. These beam energies were chosen to study the contribution of the Cherenkov light to the total output. [Preview Abstract] |
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