Adam Bernstein, Rare Event Detection Group Leader, Physics and Life Sciences Directorate, Lawrence Livermore National Laboratory On behalf of the LUX collaboration May 2016 International Symposium on revealing the history of the universe with underground particle and nuclear research 2016 This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344. Lawrence Livermore National Security, LLC Lawrence Livermore National Laboratory 1 LLNL-PRES-xxxxxx
• Introduction to LUX, the Large Underground Xenon detector and collaboration • What is new since our last limit publication in 2013 ? • Next steps for LUX • LZ status and plans Total mass – 0.37 T WIMP Active mass – 0.25 T WIMP Fiducial mass – 0.145 T Lawrence Livermore National Laboratory 2 LLNL-PRES-xxxxxx
Brown SD School of Mines LUX Collaboration meeting, UCSB, February 2016 Richard Gaitskell ! PI, Professor Samuel Chung Chan ! Graduate Student Xinhua Bai ! PI, Professor Dongqing Huang ! Graduate Student Doug Tiedt ! Graduate Student Casey Rhyne ! Graduate Student Will Taylor ! Graduate Student SDSTA James Verbus ! Graduate Student David Taylor ! Project Engineer Markus Horn ! Research Scientist Imperial College London Mark Hanhardt ! Support Scientist Henrique Araujo ! PI, Reader SUNY at Albany Tim Sumner ! Professor Alastair Currie ! Postdoc Matthew Szydagis ! PI, Professor Adam Bailey ! Graduate Student Jeremy Mock ! Postdoc Khadeeja Yazdani ! Graduate Student Sean Fallon ! Graduate Student Steven Young ! Lawrence Berkeley + UC Berkeley Graduate Student Texas A&M Bob Jacobsen ! PI, Professor Murdock Gilchriese ! Senior Scientist Kevin Lesko ! Senior Scientist James White † PI, Professor Michael Witherell ! Lab Director Robert Webb ! PI, Professor Simon Fiorucci ! Scientist Rachel Mannino ! Graduate Student Peter Sorensen ! Scientist Paul Terman ! Graduate Student Attila Dobi ! Postdoc Daniel Hogan ! Graduate Student UC Davis Mia Ihm ! Graduate Student Kelsey Oliver-Mallory ! Graduate Student Mani Tripathi ! PI, Professor Lawrence Livermore Britt Hollbrook ! Senior Engineer John Thmpson ! Development Engineer Adam Bernstein ! PI, Leader of Adv. Detectors Group Dave Herner ! Senior Machinist Kareem Kazkaz ! Staff Physicist Ray Gerhard ! Electronics Engineer University of Edinburgh Jingke Xu ! Postdoc Aaron Manalasay ! Postdoc University of South Dakota Brian Lenardo ! Graduate Student Scott Stephenson ! Postdoc Alex Murphy ! PI, Reader James Moard ! Graduate Student Dongming Mei ! PI, Professor Paolo Beltrame ! Research Fellow LIP Coimbra Sergey Uvarov ! Graduate Student Chao Zhang ! Postdoc James Dobson ! Postdoc Jacob Cutter ! Graduate Student Angela Chiller ! Graduate Student Isabel Lopes ! PI, Professor Maria Francesca Marzioni ! Graduate Student Jose Pinto da Cunha ! Assistant Professor Chris Chiller ! Graduate Student Tom Davison ! Graduate Student Vladimir Solovov ! Senior Researcher UC Santa Barbara Francisco Neves ! Auxiliary Researcher Alexander Lindote ! Postdoc University of Maryland Yale → University of California Berkeley Harry Nelson ! PI, Professor Claudio Silva ! Postdoc Susanne Kyre ! Engineer Paulo Bras ! Graduate Student Carter Hall ! PI, Professor Daniel McKinsey ! PI, Professor Dean White ! Engineer Richard Knoche ! Graduate Student Carmen Carmona ! Project Scientist Ethan Bernard ! Research Scientist SLAC Nation Accelerator Laboratory Jon Balajthy ! Scott Haselschwardt ! Graduate Student Graduate Student Scott Hertel ! Postdoc Curt Nehrkorn ! Graduate Student Thomas Shutt ! Kevin O’Sullivan ! Postdoc PI, Professor Melih Solmaz ! Graduate Student Dan Akerib ! PI, Professor University of Rochester Elizabeth Boulton ! Graduate Student Kim Palladino ! Project Scientist Nicole Larsen ! Graduate Student Tomasz Biesiadzinski ! Research Scientist University College London Frank Wolfs ! PI, Professor Evan Pease ! Graduate Student Christina Ignarra ! Research Scientist Wojtek Skutski ! Senior Scientist Brian Tennyson ! Graduate Student Wing H To ! Research Scientist Chamkaur Ghag ! PI, Lecturer Eryk Druszkiewicz ! Graduate Student Wei Ji ! Graduate Student Lucie Tvrznikova ! Graduate Student Sally Shaw ! Graduate Student Dev Ashish Khaitan ! Graduate Student T.J. Whitis ! Graduate Student Mongkol Moongweluwan ! Graduate Student Lawrence Livermore National Laboratory 3 LLNL-PRES-xxxxxx
§ Coherent Elastic § Weakly Interacting Neutrino Nucleus Massive Particle Scattering (fast, light) Scattering (slow, heavy) ν + Xe → ν + Xe WIMP + Xe → WIMP + Xe ¯ ν WIMP ¯ WIMP ν Z 0 E ν ~1 − 50 MeV λ ~ a few fm λ ~ a few fm M = 100 GeV (e.g.) M = ~ 1 meV Lawrence Livermore National Laboratory 4 LLNL-PRES-xxxxxx
Annihilation (What the universe may have done/be doing) DM particle fermion ‘Direct Detection’: scattering with ordinary matter (LUX and others ) DM particle fermion Production (LHC, early cosmos) Lawrence Livermore National Laboratory 5 LLNL-PRES-xxxxxx
Look for anomalous nuclear recoils in a low-background detector. Rate = N ρ σ <v>. σ ~ A 2 à due to coherence 100 GeV WIMP recoil energy E R ≈ ½ m Xe c 2 β 2 ≈ 30 keV General requirements: • Deep underground laboratory • Low energy threshold • Low radioactivity • Gamma ray rejection • Neutron shielding • Scalability • Patience • Obsessiveness Lawrence Livermore National Laboratory 6 LLNL-PRES-xxxxxx
ü A = 132 – enhanced WIMP interaction probability due to coherence (A 2 ) ü Density = 3 g/cc – self-shielding/ fiducialization for unwanted gammas ü High scintillation and ionization yield – natural, no dopants ü No long lived radioactive isotopes ü ratio of scintillation and ionization is different for E&M v. nuclear recoils ü High purity attainable à long e- drift lengths ü ‘Easy’ cryogenics with liquid nitrogen or mechanical cooling Lawrence Livermore National Laboratory 7 LLNL-PRES-xxxxxx
§ primary or S1 scintillation (prompt photons generated in liquid start the TPC clock) (charge) and: secondary or S2 scintillation (delayed electrons, each converted to hundreds of photons in gas blanket) (light) § Good electron drift properties § Large self-shielded target mass § 3-D signal localization to ~1 mm § Powerful discrimination between S1/S2 ratio differs for nuclear/E&M recoils nuclear and electromagnetic recoils Lawrence Livermore National Laboratory 8 8 LLNL-PRES-xxxxxx
Water Tank Thermosyphon Titanium Cans - arXiv:1112.1376 Top PMT Array 49cm Field Cage and 59cm Teflon Reflector Panels Detector Stand • 370 kg Lxe, 145 kg fiducial (latest) 145 • 370 kg LXe (100 kg fiducial) • 122 PMTS (QE ~30% @ 175nm • 122 PMTs (QE~30% @ 175nm) • Low Radioactivity Materials • Low radioactivity materials • >1kW Cooling Power (Thermosyphons) • > 1 kW cooling power from thremosyphons 2” Hamamatsu R8778 PMTs • 70,000 gallons of DI water, dissolved O 2 <0.5 ppb, • 70,000 gallons of DI water - arXiv:1205.2272 Rn content < 100 mBq/m 3 • Rn content <100 mBq/m 3 Bottom PMT Array Lawrence Livermore National Laboratory 9 LLNL-PRES-xxxxxx
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Z position is determined by the time between S1 and S2 (electron drift speed of 1.5 mm/microsecond) log10 X-Y position is determined by fitting the S2 hit pattern evts/keVee/kg/day relative to measured light response functions Reconstruction of XY from events near the anode grid resolves grid wires with 5 mm pitch. LUX fiducial volume (from first analysis) Lawrence Livermore National Laboratory 13 LLNL-PRES-xxxxxx
In the last few months: • Spin Independent WIMP limits with 10 3 better sensitivity at low mass then our previous world record (PRL.116.161301) • Spin Dependent WIMP limits – also the most sensitive in the world – for neutrons, and competitive for protons (PRL.116.161302) Coming up: • Completed 300 day LUX acquisition– 3x more data – analysis in progress • Completion of major external review of the LZ design ‘CD-2’ Around the corner • The bittersweet LUX decommissioning this fall ! • Preparations for LZ at the Sanford Laboratory Lawrence Livermore National Laboratory 14 LLNL-PRES-xxxxxx
• high statistics electron recoil calibration with tritium source (PRD.93.072009) • new in situ neutron recoil calibrations lower our energy cutoff for accepting events: 3 keV à 1 keV • Improved understanding of recombination and electromagnetic energy scale The work of our energetic and bright cadre of post-docs and students is on display at the APS April 2016 meeting www.aps.org/meetings/april/ Lawrence Livermore National Laboratory 15 LLNL-PRES-xxxxxx
170,000 events Well known distribution Spans the WIMP search region Uniform throughout xenon volume – permits calibration at detector center Response persists even at 1 keV Improved measurement of ER charge/light yields compared to previous LUX analysis Completely removed in ~6 hours Lawrence Livermore National Laboratory 16 LLNL-PRES-xxxxxx
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