DOCSLIB.ORG

Current XENON Collaboration

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Current XENON Collaboration Current XENON Collaboration Columbia University Elena Aprile (PI), Karl-Ludwig Giboni, Sharmila Kamat+, Pawel Majewski+, Kaixuan Ni*, Bhartendu Singh+ and Masaki Yamashita+ Brown University Richard Gaitskell, Peter Sorensen*, Luiz De Viveiros* University of Florida Laura Baudis, David Day* Lawrence Livermore National Laboratory Adam Bernstein, Chris Hagmann and Celeste Winant+ Princeton University (move CWRU Jan 2005->) Tom Shutt, John Kwong* Rice University Uwe Oberlack ,Omar Vargas* +PostDoc *Grad Yale University Daniel McKinsey, Richard Hasty+, Angel Manzur* Gaitskell Brown University XENON Dark Matter Collaboration CfCP workshop, Dec 2004 v02 <1> XENON Event Discrimination: Electron or Nuclear Recoil? Within the xenon target: • Neutrons, WIMPs => Slow nuclear recoils => PMT Array strong columnar recombination (not all tubes shown) => Primary Scintillation (S1) preserved, but Ionization (S2) strongly suppressed Time • γ, e-, µ, (etc) => Fast electron recoils => Gas phase => Weaker S1, Stronger S2 - - Anode e - e e - Proportional e E Liq. Surface Ionization signal from nuclear recoil too small to be directly AG - - detected => extract charges from liquid to gas and detect e - e Grid ~1 µs width e - much larger proportional scintillation signal => dual phase e 0–150 µs depending on depth Electron Drift Simultaneously detect (array of UV PMTs) primary - - e - e ~2 mm/µs (S1) and proportional (S2) light => e e- EGC Distinctly different S2 / S1 ratio for e / n recoils Primary provide basis for event-by-event discrimination. ~40 ns width Liquid phase Cathode Challenge: ultra pure liquid and high drift field to Light Signal preserve small electron signal (~20 electrons) ; UV ~175 nm efficient extraction into gas; efficient detection of photons E > E small primary light signal AG GC (~ 200 photons) associated with 16 keVr Interaction (WIMP or Electron) Gaitskell Addition of CsI Photocathode at base CsI is possible option being A tertiary signal can be generated evaluated for prototype design from absorbing primary photons by CsI photocathode in LXe: PMT Array (not all tubes shown) - No transmission loss Time - high QE >20% (3 kV/cm) CsI Tertiary Gas phase Note: 16 keV nuclear recoil: Anode EAG Liq. Surface ≈ 200 photons 150 µs (if 30 cm Grid before applying efficiencies for chamber) geometry and PMT QE. EGC Also ionization signal Primary ≈ 7-20 electrons ~40 ns width (assumes high field 8 kV/cm) e- e- CsI Light Signal UV ~175 nm Cathode photons EAG > EGC Interaction (WIMP or Electron) Gaitskell WIMP Recoil Spectrum o Calculated differential and integrated event rates for E>Er for Xe , Ar and Ge o Total event rate per mass in a Xe detector with a threshold of 16 keVr is identical to that of a Ge detector with a lower threshold of 10 keVr o Ar detector with a threshold of 40 keVr would have a total event rate per mass which is 1/5 of Xe Xe Eth=16 keVr gives 0.1 event/kg/day (50% of zero thresh. sig.) Xe Rate enhanced by " high A, but low threshold dN Xe Eth=36 keVr gives (10% necessary to avoid Form of zero thresh. sig.) # dE Factor suppression Er Example cross-section shown is at current (90%) ! exclusion limits of existing experiments Gaitskell Brown University XENON Dark Matter Collaboration CfCP workshop, Dec 2004 v02 <4> XENON R&D: Dual Phase 3D XeTPC Prototype XENON Set-up at Columbia Nevis Lab CsI PC in LXe. • Pulse Tube Refrigerator used to liquefy and maintain LXe at –95.1 ± 0.05 C • Array of 7 PMTs (Hamamatsu R9288) directly coupled to the Xe active volume • Fast and Slow digitizers for direct and proportional light waveforms • Drift Field > 1kV/cm; Extraction Field > 10 kV/cm • Calibration with gamma (Co-57), alpha (Po-210) and neutronSept. (AmBe '03) sources. Gaitskell Brown University XENON Dark Matter Collaboration CfCP workshop, Dec 2004 v02 <5> XENON10:Cryogenic System and Xe Purification ~ 120 liters of LXe for target and shield. Pulse Tube Refrigerator with ~ 100 W cooling power (heat load on the XENON100 detector estimated at ~ 50W), used for keeping LXe at – 100 C within 0.1 degree. Pre-cooling (~1 day) and Xe liquefaction (~2 days) with same PTR. Hot Getter: Ba/Ti/V Pellets 350 degC - Remove H2O+O2, but not hot enough for more Gaitsckoelml pBrleowxn m Unoilveecrsuitlye s . T i S p a r k P u rXifEieNrO Nw Dilal rbk eM aettvear lCuoalltaebodr.ation CfCP workshop, Dec 2004 v02 <7> > 1m Drift Electron Attenuation Length XENON goal of 30 cm drift and ~few kV/cm E-field necessary for detection of ~ 20 e- signal (from 16 keV Xe recoil); requires purity < 1 ppb O2 equivalent. Have built & tested a dedicated Gas Purification System with continuous circulation through High-temp Getter. Gaitskell Brown University XENON Dark Matter Collaboration CfCP workshop, Dec 2004 v02 <8> R&D Milestone: QF Measurement Current data are inconsistent & do not extend to the low-energy CU RARAF 2.2 MeV neutrons (~10-30 keV) region, of interest to next-generation DM searches: p(t,3He)n LXe Recoil (keV) Measured QF Authors Borated Akimov, et. al. Polyethylene 40 - 70 0.22 ± 0.01 2002 Arneodo, et. al. Lead 45 - 110 ~ 0.2 2000 Bernabei, et. al. 35 - 70 0.45 ± 0.10 2001 LXe L ~ 20 cm θ BC501A scintillator tags recoil events: BC501A Gaitskell Brown University XENON Dark Matter Collaboration CfCP workshop, Dec 2004 v02 <9> QF: Preliminary Results 56.5 keV NR 15.5 keV NR - Electron equivalent Energy scale calibrated with 57Co spectrum & compared with MC - Multiple scattering makes low-E data more difficult to interpret Gaitskell Brown University XENON Dark Matter Collaboration CfCP workshop, Dec 2004 v02 <10> Dual-Phase Discrimination Primary/Secondary Discrimination Gaitskell Brown University XENON Dark Matter Collaboration CfCP workshop, Dec 2004 v02 <13> XENON10 Schematic of Detector and Shield Design 16 Outer PMTs Polyethylene (30cm, 2.2 tonnes ) Pb (23 cm, 31 tonnes ) Stainless Steel Cryostat (100 kg) Teflon 7 Inner PMTs (7 x R9288) Xe Gas Liquid Xe – Inner Region (ø18 cm, h 15 cm, 12 kg) CsI Photo Cathode Liquid Xe – Veto Region Copper (2.5cm) (thickness 5cm, 50 kg) (parameters used in Monte Carlo) Gaitskell Brown University XENON Dark Matter Collaboration CfCP workshop, Dec 2004 v02 <14> XENON10 – Neutron Background Event Rates • Neutron Background Event Rates for XENON10 Module o XENON10 Goal is 1.3 evts/10kg/month => 360 µdrur (100GeV WIMP) o Assumes LNGS 24 µ/m2/day (No muon veto required) Inner Event Rate (no cuts) Source (@ 2 keVr) [ µdrur ] PMT/Stainless Internal (α,n) Neutrons 0.01 (α,n)/Fission Neutrons from Cavern 15 Muon-Induced Neutrons from Pb Shield 10 * Muon-Induced Neutrons from Poly Shield 6 * High Energy Muon-Induced Neutrons 3 ** from Rock Total 34 µdrur XENON10 Goal is 360 µdrur * factor 2 uncertainty ALSO Alpha decays inner surfaces -> daughter (nuclear) recoils ** factor 4 uncertainty - Control Rn plating / Edge fiducial cuts µdrur = 10-6 evts/keVr/kg/day Gaitskell Brown University XENON Dark Matter Collaboration CfCP workshop, Dec 2004 v02 <16> XENON10 – Gamma/Electron Background Event Rates • Gamma Background Event Rates (8 < E < 16keVee) for XENON10 Module o XENON10 Goal is 140 mdruee gammas before electron recoil rejection (x200) o Assumes using 5 cm outer LXe active veto and inner multiple scatters cut Inner Event Rate with LXe outer veto Source (8 < E <16 keVee) [ mdruee ] 7 Inner PMTs 9 (5 *) 16 Outer PMTs 0.64 HV Shaping Ring Resistors 1.6 Stainless Steel Cryostat 12 Polyethylene Shield 9 External/Pb shield Gammas < 5 Teflon Walls < 1 85Kr (< 0.1 ppb) < 6 210Pb Brem (Pb shield 30 Bq/kg) < 5 Tritium (removed by Gas sep./getter) Total ~< 40 mdru XENON10 Goal is 140 mdruee before 200x rejection * if a 1 cm depth cut is made at top of inner LXe mdruee = 10-3 evts/keVee/kg/day Gaitskell Brown University XENON Dark Matter Collaboration CfCP workshop, Dec 2004 v02 <17> TPC and PMTs Details Gaitskell Brown University XENON Dark Matter Collaboration CfCP workshop, Dec 2004 v02 <21> Light Collection • Fraction of photons from light source hitting photo-sensors Photon Hit PMTs CsI Fractions * 7 x ø5 cm Photocathode Liquid Evt α1 = 3.3% α3 = 69.1% (±0.8) (±8) “Anode” ~0.5 cm above liquid surface Gas Electro- α = 13.3% α = 41.5% 2 4 “Grid” just below liquid surface luminescence (±2) (±3) ( ) indicate characteristic variation of values 3.1 cm drift of α as position of source is moved around “Cathode” 9 x 9 cm CsI Photocathode • The PMTs suffer reduced collection of photons from liquid because of Total Internal Reflection at liquid-gas interface (~20% solid angle acceptance) • CsI covers entire lower surface of chamber * Photon Monte Carlo (Kaixuan Ni, Columbia) Gaitskell Brown University XENON Dark Matter Collaboration CfCP workshop, Dec 2004 v02 <22> Signals (Photoelectron # in PMTs) • Factors determining initial scintillation & ionization conversion to signals in PMTs “Anode” ~ +4 kV SIGNAL Sn is the signal, type n, in phe (photoelectrons) “Grid” - 0 V SOURCE ne number of electrons from event site np number of photons from event site “Cathode” ~ -10 kV PHOTON- > ELECTRON QPMT PMT efficiency = (QEPMT ~ 20%) " (CEPMT ~ 60%) ~ 12%) QCsI CsI quantum efficiency (~ 20% at 3 kV/cm) S1 = (QPMT"1)np GAS ELECTROLUMINESENCE S2 = Q " # $ $ n #gas photons per electron in gas (~100 -250, EAnode & P dep.) ( PMT 2)( gas ex d ) e S3 = (QPMT" 2) #gas$ex$ d% (QCsI" 3)np ELECTRON DRIFT ( ) S4 = Q " # $ $ % Q " # $ $ n $d electron drift efficiency (Xe clean ~ 100%), ( PMT 2)( gas ex d )( CsI 4 )( gas ex d ) e $ electron liquid-gas extraction efficiency (~ 85%-100%) ex S2 S3 # # " = 2 3 $ 7 S1 S4 #1# 4 ! Gaitskell Brown University XENON Dark Matter Collaboration CfCP workshop, Dec 2004 v02 <23> ! ! Cathode Feedback 4kV Anode Voltage 0V “Anode” ~ +4 kV “Grid” - 0 V “Cathode” ~ -10 kV • Present mode of operation … to prevent total saturation of feedback o Anode Voltage - is triggered on initial light (n>2 phe) in PMTs o and then shut down ~2 drift times (27 us) later.
Load more

Recommended publications
  • First Science Results from the LUX Dark Matter Experiment
    First Science Results from the LUX Dark Matter Experiment Daniel McKinsey, LUX Co-Spokesperson, Yale University Richard Gaitskell, LUX Co-Spokesperson, Brown University on behalf of the LUX Collaboration http://luxdarkmatter.org Sanford Underground Research Facility OctoberS 30, 2013 LUX Dark Matter Experiment / Sanford Lab Rick Gaitskell (Brown) / Dan McKinsey (Yale) 1 Composition of the Universe The Higgs particle has been discovered, the last piece of the Standard Model. But as successful as it has been, the Standard Model describes only 5% of the universe. The remaining 95% is in the form of dark energy and dark matter, whose fundamental nature is almost completely unknown. Image: X-ray: NASA/CXC/CfA/M.Markevitch et al.; www.quantumdiaries.org Optical: NASA/STScI; Magellan/U.Arizona/D.Clowe et al.; Lensing Map: NASA/STScI; ESO WFI; Magellan/U.Arizona/D.Clowe et al. LUX Dark Matter Experiment / Sanford Lab 2 Rick Gaitskell (Brown) / Dan McKinsey (Yale) 2 Evidence for Dark Matter Galaxy rotation curves The cosmic microwave background www.quantumdiaries.org Image: ESA and the Planck collaboration Gravitational lensing • 27% of the energy composition of the universe • Properties: • Stable and electrically neutral • Non-baryonic • Non-relativistic • Estimated local density: 0.3±0.1GeV·cm-3 • Candidates: WIMPs, axions, dark photons,... Colley, Turner, Tyson, and NASA LUX Dark Matter Experiment / Sanford Lab 3 Rick Gaitskell (Brown) / Dan McKinsey (Yale) 3 Weakly Interacting Massive Particles (WIMPs) A new particle that only very weakly interacts with ordinary matter could form Cold Dark Matter - Formed in massive amounts in the Big Bang. - Non-relativistic freeze-out.
    [Show full text]
  • Broader Impacts of XENON Research
    XENON: A Liquid Xe Dark Matter Search Experiment at LNGS Columbia University: Elena Aprile, Karl-Ludwig Giboni, Pawel Majewski, Kaixuan Ni, Bhartendu Singh, Masaki Yamashita Brown University: Richard Gaitskell, Peter Sorensen, Luiz DeViveiros University of Florida: Laura Baudis, David Day Lawrence Livermore National Laboratory: William Craig, Adam Bernstein, Chris Hagmann Princeton University: Tom Shutt, John Kwong, Kirk McDonald Rice University: Uwe Oberlack, Omar Vargas Yale University: Daniel McKinsey, Richard Hasty, Hugh Lippincott Contact person Elena Aprile ([email protected]) Letter of Intent 1 1. The physics case The goal of the XENON experimental program is direct detection of dark matter in the form of weakly interacting massive particles (WIMPs) with an array of ten identical liquid Xe detector modules each with a 100 kg fiducial mass (XENON100).Current theoretical models indicate that WIMP interaction rates probably lie between the current sensitivity of existing experiments which is equivalent to ~0.25 evts/kg/day and ~2 evts/100 kg/yr normalized for a Xe target. The best prospects for the unambiguous identification of a WIMP nuclear recoil signal lie in detectors that have negligible radioactive background competing with the dark matter signal. This can be achieved principally by using nuclear recoil discrimination in order to veto competing electron recoil events (associated with gamma and beta backgrounds), effective neutron shielding, and through the operation of a large homogeneous detector volume with 3-D position resolution. The latter information can be used to select single hit events characteristic of a WIMP interaction while rejecting multiple hit events associated with backgrounds that propagate from the edge of the detector into the fiducial volume.
    [Show full text]
  • Two-Phase Xenon Time Projection Chambers for WIMP Searches and Other Applications
    Two-Phase Xenon Time Projection Chambers for WIMP Searches and Other Applications Nicole A. Larsen Yale University Department of Physics Advisor: Daniel McKinsey Thesis Prospectus May 24, 2012 Abstract Astronomical evidence indicates that 23 % of the energy density in the universe is comprised of some form of non-standard, non-baryonic matter that has yet to be observed. One of the predominant theories is that dark matter consists of WIMPs (Weakly Interacting Massive Particles), so named be- cause they do not interact electromagnetically or through the strong nuclear force. In direct dark matter detection experiments the goal is to look for evidence of collisions between WIMPs and other particles such as heavy nuclei. Here, the challenge is to measure exceedingly rare interactions with very high precision. In recent years xenon has risen as a medium for particle detection, exhibiting a number of desirable qualities that make it well-suited for direct WIMP searches. The LUX (Large Underground Xenon) experiment is a 350-kg xenon-based direct dark matter detection experiment currently deployed at the Homestake Mine in Lead, South Dakota, consisting of a two-phase (liq- uid/gas) xenon time projection chamber with a 100-kg fiducial mass. Its projected sensitivity for 300 days of underground data acquisition is a cross-section of 7 × 10-46 cm2 for a WIMP mass of 100 GeV, representing an improvement of nearly an order of magnitude over previous WIMP-nucleon scattering cross-section limits. Furthermore, two-phase xenon-based technologies are useful in many other applications, in- cluding other fundamental physics searches, imaging of special nuclear materials, and medical imaging.
    [Show full text]
  • Progress Towards a Measurement of the Electric Dipole Moment of the Electron Using Pbo∗
    Abstract Progress Towards a Measurement of the Electric Dipole Moment of the Electron using PbO¤ Sarah Rachel Bickman 2007 We have proposed and begun implementing an experiment to look for an electric dipole 3 + moment (EDM) of the electron, de, using the metastable a(1) § state of the PbO molecule. A non-zero measurement of de within the next few orders of magnitude beyond the current limit ¡27 of jdej < 1:6£10 e-cm [1] would be clear evidence for physics beyond the standard model. We ¤ have designed and built a stable apparatus for the measurement of de using PbO in a heated vapor cell. Using this apparatus, the ­ doublet splitting in the a(1) J=1 state was measured to be 11.214(5) MHz. Without an applied electric ¯eld, the di®erence in g-factors between the ­ doublet states was found to be ±g=-31(9)£10¡4. Measurements of the Stark shift were found to be consistent with previous measurements [2]. The counting rate has been optimized and agrees with models. Three di®erent types of detectors with associated low-noise preampli¯ers were built and tested. To improve the sensitivity, an alternate detection scheme using reexcitation to the C0 state was explored and ultimately rejected in the form proposed here. In the ¯rst generation experiment, with the current fluorescence detection along the a(1)!X transition, the ¡25 p expected sensitivity to an electron EDM is ±de ¼10 e cm/ day. Two proposals for second generation experiments are considered. Progress Towards a Measurement of the Electric Dipole Moment of the Electron using PbO¤ A Dissertation Presented to the Faculty of the Graduate School of Yale University in Candidacy for the Degree of Doctor of Philosophy by Sarah Rachel Bickman Dissertation Director: David Paul DeMille December 2007 Copyright °c 2007 by Sarah Rachel Bickman All rights reserved.
    [Show full text]
  • Paolo Beltrame University of Edinburgh (On Behalf of the LUX and LZ Collaborations)
    Recent results from LUX and status of LZ Paolo Beltrame University of Edinburgh (on behalf of the LUX and LZ collaborations) 51st Rencontres de Moriond Electro Weak and Unified Theories La Thuile, 12-19 March, 2016. 1 Outline • The Large Underground Xenon (LUX) experiment New results on WIMP searches and calibration • The LUX-ZEPLIN experiment Paolo Beltrame 2 Moriond EW 2016 Direct search Dark matter (DM) Milky Way’s halo => flux on Earth ~ 105 cm-2s-1 ρχ ~ 0.3 GeV/cm3 and 100 GeV/c2 Basic goal: search for nuclear recoil from DM elastic scattering. Simple dynamics: cross section ∝(form-factor)2 Spin-independent: nucleon form-factor gives rise to A2 enhancement due to coherence. The dependence on q2 is also contained in the form-factors. Spin-dependent: form-factor depends on nuclear spin. No coherence enhancement. Paolo Beltrame 3 Moriond EW 2016 LargeThe Underground LUX Collaboration Xenon Brown Collaboration Meeting, University at Albany, October 2015 SD School of Mines Richard Gaitskell PI, Professor Xinhua Bai PI, Professor Simon Fiorucci Research Associate Doug Tiedt Graduate Student Samuel Chung Chan Graduate Student Dongqing Huang Graduate Student Casey Rhyne Graduate Student SDSTA Will Taylor Graduate Student David Taylor Project Engineer James Verbus Graduate Student Mark Hanhardt Support Scientist Imperial College London Henrique Araujo PI, Reader Texas A&M Tim Sumner Professor Alastair Currie Postdoc James White † PI, Professor Adam Bailey Graduate Student Robert Webb PI, Professor Khadeeja Yazdani Graduate Student Rachel Mannino
    [Show full text]
  • UC Irvine UC Irvine Previously Published Works
    UC Irvine UC Irvine Previously Published Works Title Dark matter in the coming decade: Complementary paths to discovery and beyond Permalink https://escholarship.org/uc/item/5s49x6cx Authors Bauer, D Buckley, J Cahill-Rowley, M et al. Publication Date 2015-12-03 DOI 10.1016/j.dark.2015.04.001 Peer reviewed eScholarship.org Powered by the California Digital Library University of California Dark Matter in the Coming Decade: Complementary Paths to Discovery and Beyond Sebastian Arrenberg, University of Z¨urich; Howard Baer, University of Oklahoma; Vernon Barger, University of Wisconsin; Laura Baudis, University of Z¨urich; Daniel Bauer, Fermilab; James Buckley, Washington University; Matthew Cahill-Rowley, SLAC; Randel Cotta, University of California, Irvine; Alex Drlica-Wagner, SLAC; Jonathan L. Feng, University of California, Irvine; Stefan Funk, SLAC; JoAnne Hewett, SLAC; Dan Hooper∗, Fermilab; Ahmed Ismail, SLAC; Manoj Kaplinghat∗, University of California, Irvine; Kyoungchul Kong, University of Kansas; Alexander Kusenko, University of California, Los Angeles; Konstantin Matchev∗, University of Florida; Mathew McCaskey, University of Kansas; Daniel McKinsey, Yale University; Dan Mickelson, University of Oklahoma; Tom Rizzo, SLAC; David Sanford, Caltech; Gabe Shaughnessy, University of Wisconsin; William Shepherd, University of California, Santa Cruz; Tim M. P. Tait∗, University of California, Irvine; Xerxes Tata, University of Hawaii; Sean Tulin, University of Michigan; Alexander M. Wijangco, University of California, Irvine; Matthew
    [Show full text]
  • Yale Department of Physics Summer 2013
    Yale Department of Physics Summer 2013 Greetings from the (Former) Department Chair — When I became Department Chair the Department of Energy, and with colleagues across the in 2007, I immediately began wider physics community, and during this time, the Tandem planning my first Newsletter. It accelerator was shut down. Ultimately (skipping over the is now 2013 and you are reading many details), this process culminated in the appointment of the one and only newsletter I’ve Karsten Heeger as a senior faculty member and new Director of managed to put together during my WNSL, as well as the junior appointment of Reina Maruyama term. It’s a sign that a lot of other (see article on faculty appointments on page 3). Together with things were happening, and as I colleagues in particle and AMO physics, WNSL now represents step down as Department Chair, I a center of excellence in weak interaction physics, as well as a am really pleased to tell you about leader in the development of detectors based on noble gases, all the wonderful things we have including the liquid Argon technology that will be used for accomplished, despite some challenging financial times. an eventual long-baseline neutrino oscillation experiment. My first priority as Chair was strategic planning for the The Physics Department grew and turned over significantly coming decade. Over a period of several months in the fall of over the past decade, bringing a lot of excitement and vitality. 2007, we held faculty discussions nearly every week. Six faculty My predecessor as Chair, Shankar, hired 16 new faculty, and I members gave overview talks, outlining the science landscape have hired 7.
    [Show full text]
  • Sophia Sanchez-Maes (YC’2019 Physics (Intensive) Commencement Is May 21, 2018
    Sophia Sanchez-Maes (YC’2019 Physics (Intensive) Commencement is May 21, 2018. Summer Sessions for 2018 Major) has won the Outstanding Undergraduate run as follows: Session A – May 28-June 29 and Session B – July Research Award from the American Institute of Physics 2-August 3. Society of Physics Students. Click here for full story. For more news please see http://physics.yale.edu/news Tuesday, May 15 Wright Lab Event WIDG Seminar. Zack Lasner, Yale University, “Probing TeV physics in ThO: an improved measurement of the electron’s electric dipole moment”, WLC For further information on any of the items included 245 at 12:00pm. Lunch will be served starting at 11:45am outside WLC 245. RSVP required for lunch. here or if you would like to contribute to the next newsletter, send email to Daphne Klemme. Wednesday, May 16 Department of Molecular, Cellular and Developmental Biology Seminar. Manuel Ascano, Vanderbilt § University School of Medicine, “Host-Pathogen Interactions: Nucleic Acid Detection and Co-option in Innate Immunity”, SCL Please click here for updates on the Yale Science 160 at 4:00pm. Host: Anna Pyle. Tea at 3:45pm. Building, including a new logistics plan. The project Friday, May 18 Systems Biology Institute & Cancer Systems encompasses the construction of a new state of the art Biology Symposium. “The Systems Biology of Phenotypic sciences laboratory at the approximate location of the Switches: Cancer Invasion and Beyond”, Keynote Speaker: demolished J.W. Gibbs building, a comprehensive Douglas A. Lauffenburger, MIT. Yale West Campus Conference renovation of the KBT Plaza, a lecture hall, and a Center 8:30am-5:00pm.
    [Show full text]
  • Scintillation Efficiency and Ionization Yield of Liquid Xenon for Mono
    Scintillation efficiency and ionization yield of liquid xenon for mono-energetic nuclear recoils down to 4 keV 1 1, 1 1, 1, 1, A. Manzur, A. Curioni, ∗ L. Kastens, D.N. McKinsey, y K. Ni, z and T. Wongjirad x 1Department of Physics, Yale University, P.O. Box 208120, New Haven, CT 06520, USA (Dated: October 27, 2018) Liquid Xenon (LXe) is an excellent material for experiments designed to detect dark matter in the form of Weakly Interacting Massive Particles (WIMPs). A low energy detection threshold is essential for a sensitive WIMP search. The understanding of the relative scintillation efficiency ( eff) and ionization yield of low energy nuclear recoils in LXe is limited for energies below 10 keV. In thisL paper, we present new measurements that extend the energy down to 4 keV, finding that eff decreases with decreasing energy. We also measure the quenching of scintillation efficiency dueL to the electric field in LXe, finding no significant field dependence. PACS numbers: 95.35.+d, 29.40.Mc, 95.55.Vj I. INTRODUCTION coil energy (Er), becomes necessary for determining the nuclear energy scale and, therefore, the WIMP detection Liquid xenon is increasingly used as the detection ma- sensitivity. Eee is inferred from the scintillation signal yield due to monoenergetic electron recoils. has no terial in direct searches for WIMP dark matter [1]. Recent Leff developments in two-phase (gas/liquid) xenon detec- units and is defined at zero electric field in LXe relative tors [2–4] has resulted in stringent limits on the WIMP- to 122 keV gamma rays.
    [Show full text]
  • The LUX Dark Matter Experiment
    The LUX Dark Matter Experiment Dan McKinsey LUX Co-Spokesperson Yale University 8th Patras Workshop on Axions, WIMPs, and WISPs , July 18th, 2012 Xenon as a WIMP Target Inert High density (3g/cm3 for liquid) High A2 increases spin-independent cross-section Some isotopes sensitive to spin-dependent interactions Bright scintillator with fast (~ns) response High electron mobility Long ionization drift lengths (several meters) demonstrated No long-lived radioactive isotopes Low cost (~$1000/kg) and readily available in large quantities Easy to scale Direct WIMP Detection with Liquid Xenon Goal: observe recoils between a WIMP and a target nucleus Equation for WIMP interaction cross section Recoil energy deposited in three channels: Scintillation (photons) Ionization (charge) Heat (phonons) LUX is a two-phase xenon WIMP detector Z position from S1 – S2 timing X-Y positions from S2 light pattern Reject gammas by charge (S2) to light (S1) ratio. Expect > 99.5% rejection. The LUX Detector Thermosyphon Copper shield Water tank Top PMT array Anode grid PTFE reflector Detector panels and stand Outer field cage Innercryostat cryostat Cathode grid 350 kg xenon: - 300 kg active Bottom PMT region array - 100 kg fiducial The LUX Collaboration Brown University of Maryland Richard Gaitskell PI, Professor Simon Fiorucci Research Associate Carter Hall PI, Professor Monica Pangilinan Postdoc Attila Dobi Graduate Student Jeremy Chapman Graduate Student Richard Knoche Graduate Student Carlos Hernandez Faham Graduate Student Texas A&M David Malling Graduate Student
    [Show full text]
  • Final Word Is Near on Dark-Matter Signal an Influential US Experiment Prepares to Release Its First Results
    IN FOCUS NEWS PHYSICS Final word is near on dark-matter signal An influential US experiment prepares to release its first results. BY EUGENIE SAMUEL REICH iewed end on, the arrays of photomulti­ plier tubes on the Large Underground Xenon (LUX) experiment look like Vbeds of flowers. The hope is that they will cap­ ture sparks of light emitted when particles of dark matter collide with liquid xenon. With 122 detector tubes, LUX is much more sensi­ tive than its closest rival in the competitive field of dark-matter searches — and in just days, physicists the world over will know whether that advantage has yielded definitive results. The project, based at the Sanford Under­ ground Research Facility in Lead, South Dakota, will release its first findings on 30 October. They are likely to reveal whether LUXDARKMATTER tentative dark-matter signals seen by other experiments are real, and will also inform LUX could resolve a decade-long physics debate. ongoing discussions about how much more time and money should be spent on the hunt at the University of California, Berkeley, each for dark matter. “The potential is there, and all reported tantalizing, but not statistically con­ the community is waiting with bated breath vincing, glimpses of potential dark matter; to see what they observe,” says Juan Collar, a a year later, XENON100 saw no sign of the physicist who leads a rival experiment at the stuff. That prompted heated discussion over University of Chicago in Illinois. whether the experiment was sensitive to the Elena Aprile, a physicist at Columbia Uni­ lighter dark-matter particles that might have versity in New York city who leads another been glimpsed by the other two experiments.
    [Show full text]
  • Progress Report (2005-2006).Pdf
    UConn-40870-00XX STATUS REPORT 2005-2006 (Two Year Period) Laboratory for Nuclear Science at Avery Point University of Connecticut USDOE Grant No: DE-FG02-94ER40870 Principal Investigator: Moshe Gai Table of Contents . Abstract 3 . Personnel and Facilities 3 .3 PreAmble 4 List of Projects: . The Construction of the Optical Readout Time Projection Chamber (O-TPC) 6 . Test of Oxygen Rich Gasses 8 .3 Test of the CERN-CHORUS optical readout 9 3. Test of Cirlex-THGEM Readout for a Dark Matter detectors 0 3. Test of Cirlex-THGEM in the Yale xenon cell 11 4. The Coulomb Dissociation of 8B: The Triumph of Good Science 4. Implanted Target for a Study of the 3He(4He, γ)7Be Reaction at TUNL 3 5. Dating of Marine Sediments with 0Pb 4 6. Calibration of the Yale-UConn Neutron Ball 5 7 Publications 6 7. Refereed Journals 6 7. Invited Talks, Contributions and Conference Proceedings 7 1.1 Abstract Our research program encompasses studies in Low Energy Nuclear Astrophysics (and some studies in Weak Interactions) with emphasis on High Sensitivity Experiments in Search of Rare Decays or Rare Processes that are critical for our understanding of stellar processes and the detection of Dark Matter (DM). Our research program in Nuclear Astrophysics concentrates on stellar evolution: helium burning prior to supernova and the 8B and 7Be solar neutrino flux calculated in the standard solar model. We carry out a research program at the Wright Nuclear Structure Laboratory (WNSL) at Yale University and at the Triangle University Nuclear Laboratory (TUNL) at Duke University that we consider as our main user labs.
    [Show full text]