1 / 32

The XENON Dark Matter Experiment

The XENON Dark Matter Experiment. Elena Aprile Physics Department and Columbia Astrophysics Laboratory Columbia University http:// www.astro.columbia.edu/~lxe/XENON/. Dark Energy 73%. Energy 2/3. The Case for Non-Baryonic Dark Matter Conclusion from all Evidence.

caden
Télécharger la présentation

The XENON Dark Matter Experiment

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The XENON Dark Matter Experiment • Elena Aprile • Physics Department and Columbia Astrophysics Laboratory • Columbia University • http://www.astro.columbia.edu/~lxe/XENON/

  2. Dark Energy 73% Energy 2/3

  3. The Case for Non-Baryonic Dark MatterConclusion from all Evidence WTotal = 1WL = 2/3 Wm = 1/3 >95% of the Universe composition still unidentified. Ωm >> Ωb What is this Dark Matter?

  4. LSP (neutralino) LKP (lightest Kaluza-Klein) Axions Solitons Wimpzillas, .. Different mass range and interaction rate.. Non-baryonic Cold Dark Matter Candidates Must be stable, weakly interacting and with right relic density WIMPs

  5. Produced and detected at accelerators Indirectly detected via their Annihilation in Sun, Earth, Galaxy Neutrinos,positrons, antiprotons, g-rays Cold Dark Matter Relics can be.. LHC GLAST AMS ANTARES AMANDA/ICECUBE

  6. …or can be directly detected in terrestrial detectors WIMPs scatter elastically with nuclei: Rate ~ N rc/mc <sc> N = number of target nuclei in detector rc = local WIMP density <sc> = scattering cross section From the density of dark matter in the galaxy: Every liter of space: 10-100 WIMPs, moving at 1/1000 the speed of light => Less than 1 WIMP/week will collide with an atom in 1kg material WIMP Direct Detection:a challenging task Rate: 10-1 - 10-5 /kg/day Nuclear recoil energy: 10 - 100 keV Very large background: gamma rays and neutrons from radioactivity and cosmic rays WIMP

  7. Detectors must effectively discriminate betweenNuclear Recoils (Neutrons, WIMPs)Electron Recoils (gammas, betas) Light ZEPLIN XMASS XENON WARP CRESST recoil energy Charge Heat CDMS, EDELWEISS

  8. World Wide WIMP Search Picasso x CDMS II XMASS Majorana SuperCDMS CLEAN IGEX CDMS I KIMS CsI LiF Elegant V&VI Boulby ZEPLIN I/II/III/MAX DRIFT Gran Sasso DAMA/LIBRA CRESST WARP XENON CUORE ORPHEUS EDELWEISS I/II CanFranc IGEX ROSEBUD ANAIS ArDM

  9. The XENON Experiment: Overview • Modular design: 1 ton active Xe distributed in an array of ten 3D position sensitive dual-phase (liquid/gas) XeTPCs, actively shielded by a LXe veto. • Simultaneous detection of ionization and scintillation for event-by-event discrimination of nuclear recoils from electron recoils (>99.5%) down to 16 keVr. • XENON funded by NSF and DOE. • Phase1 (XENON10) : 15 kg detector has been installed in Gran Sasso Lab ( equipment arrived on March 7, 2006). Shield construction to be completed by May 15, 2006. XENON10 physics run (June-Aug, 2006) will determine design of 1st 100 kg module • Phase2 (XENON100): Goal is data taking by late 2007. After 3 months at a background < 1x10-4 cts/keV/kg/day after rejection, the sensitivity of XENON100 would be s~2x10-45 cm2 .

  10. The XENON Collaboration Columbia University Elena Aprile (PI), Karl-Ludwig Giboni, Sharmila Kamat, Maria Elena Monzani, Kaixuan Ni*, Guillaume Plante*, and Masaki Yamashita Brown University Richard Gaitskell, Simon Fiorucci, Peter Sorensen*, Luiz DeViveiros* University of Florida Laura Baudis, Jesse Angle*, Joerg Orboeck, Aaron Manalaysay* Lawrence Livermore National Laboratory Adam Bernstein, Chris Hagmann, Norm Madden and Celeste Winant Case Western Reserve University Tom Shutt, Eric Dahl*, John Kwong* and Alexander Bolozdynya Rice University Uwe Oberlack , Roman Gomez* and Peter Shagin Yale University Daniel McKinsey, Richard Hasty, Angel Manzur* LNGS Francesco Arneodo, Alfredo Ferella* Coimbra University Jose Matias Lopes, Joaquin Santos

  11. CDMS II goal XENON Dark Matter Goals • XENON10 (2006-2007): 10 kg target ~2 events/10kg/month Equivalent CDMSII Goal for mass >100 GeV (Current CDMS limit is 10 x above this level) Important goal of XENON10 underground is to establish performance of dual phase TPC to design optimized XENON100 • XENON100 (2007-2008): 100 kg target ~2 events/100kg/month • XENON-1T (2008-2012?): 1 ton (10 x 100 kg modules) 10-46 cm2 or ~1 event/1 tonne/month Test majority of SUSY models. Discover Dark Matter! Dark Matter Data Plotterhttp://dmtools.brown.edu SUSY TheoryModels SUSY TheoryModels

  12. Why Liquid Xenon? High atomic mass (A ~ 131): favorable for SI case (s ~ A2) Odd isotope with large SD enhancement factors (129Xe, 131Xe) High atomic number (Z=54) and density (3g/cm3) => compact, self-shielding geometry ‘Easy’ cryogenics at -100 C No long-lived radioisotopes Excellent Scintillator (~NaI(Tl)) and Efficient Ionizer (W=15.6 eV) Simultaneous Light and Charge Detection => background discrimination

  13. Very Typical WIMP Signal in Xe Xe rate enhanced by high A, but low threshold necessary to avoid form factor suppression Xe Eth=16 keVr gives 0.1 event/kg/day (30% of zero thresh. sig.)

  14. Principle of Operation WIMP or Neutron nuclear recoil Gamma or Electron electron recoil

  15. Ionization & Scintillation in LXe Kubota et al. 1979, Phys. Rev.B Fast Slow

  16. Effect of Ionization Density on Time Dependence A.Hitachi PRB 27 (1983)5279

  17. XENON R&D Goals: Summary + PMTs operation in LXe + > 1 meter le in LXe + > 1 kV/cm electric field + dual phase operation + Reliable Cryogenic System + Nuclear recoil Scintillation Efficiency (10-55 keVr) + Nuclear recoil Ionization Efficiency + Electron/Nuclear recoil discrimination + Kr removal for XENON10 + Electric Field / Light Collection Simulations + Background Simulations + Materials Screening for XENON10 + Assembly of XENON10 System + Low Activity PMTs + Alternatives Readouts (SiPMs,LAAPDs,MCPs,GEMs..) Achieved Achieved Achieved Achieved Achieved Achieved AchievedAchieved Purification of 22 kg of Xe ongoing Tools Developed_Done for XENON10 Tools Developed_Done for XENON10 All major components screened AchievedVerified Hamamatsu #’s Studies ongoing

  18. Recent Highlights from XENON R&D LXe Scintillation Efficiency for Nuclear Recoils • The most important parameter for DM search • No prior measurement at low energies • Aprile at al., Phys. Rev. D 72 (2005) 072006 LXe Ionization Efficiency for Nuclear Recoils • XENON concept based on simultaneous detection of recoil ionization and scintillation • No prior information on the ionization yield as a function of energy and applied E-field • Aprile et al., PRL (2006), astro-ph/0601552 Development of XENON10 Experiment for Underground Deployment • Validated Cryogenics, HV, DAQ systems with 6kg prototype (XENON3) • Demonstrated low energy threshold and 3D position reconstruction • Installed/tested larger (15 kg) detector in same cryostat (Dec 05- Feb06) • XENON10 equipment shipped to Italy on March 2, 2006

  19. Xe-Recoils Scintillation Efficiency [Columbia and Yale] Columbia RARAF 2.4 MeV neutrons p(t,3He)n Borated Polyethylene Lead LXe L ~ 20 cm  Aprile et al., Phys. Rev. D 72 (2005) Use pulse shape discrimination and ToF to identify n-recoils BC501A

  20. Xe-Recoils Ionization Yield • 1st Measurement of the charge of low energy recoils in LXe and of the field dependence. • Charge yield surprisingly higher than expected and with very weak field dependence. Energy threshold: 10 keVr [Columbia, Brown and Case]

  21. ELASTIC Neutron Recoils INELASTIC 131Xe 80 keV  + NR Upper edge -saturation in S2 INELASTIC 129Xe 40 keV  + NR Neutron ELASTIC Recoil AmBe n-source 137Cs  source 5 keVee energy threshold = 10 keV nuclear recoil Background discrimination capability

  22. Rejection limited by edge gamma event contamination due to field irregularities nuclear recoil electron recoil improvement expected with XY position sensitive detector

  23. S2 experimental value (# of photoelectrons) Expected S2 from simulation for all possible x and y at every 1x1 mm2 pixel # of PMTs (top only) x and y found at minimum chisq Fluctuation of PMT signals (# of pe, gain, analysis error) + Uncertainties from simulation (geometry, statistical) XENON3: the first 3D sensitive dual phase XeTPC Hamamatsu R8520 PMT: Compact metal channal: 1 inch square x 3.5 cm Quantum Efficiency: >20% @ 178 nm 10 cm 10 cm

  24. a low energy event in the center, near LXe/GXe interface an edge event with long drift time S1 S1 ~ 9 keVee S2 S2 σ~2 mm σ~1 cm

  25. Edge events can be well identified Pos III Pos I Co-57 (Pos III) Pos II Co-57 (Pos I) Co-57 (Pos II)

  26. 80 keV Inelastic (131Xe) 110 keV inelastic (19F) + NR 80 keV Inelastic (131Xe) + NR 40 keV Inelastic (129Xe) + NR 40 keV Inelastic (129Xe) + NR Neutron Elastic Recoil Neutron Elastic Recoil XENON3: Edge events effectively removed by radial cut XENON3’s response to neutrons (2.5 MeV from D-D generator) at 1 kV/cm drift field

  27. Fitting from measurements by Columbia and XENON Collaborators (En in keVr), see: Aprile et al., Phys. Rev. D 72 (2005) 072006 Aprile et al., astro-ph/0601552 XENON10: Expected Position Sensitivity from Simulation 48 PMTs on top, 41 on bottom 8 inch diameter, 6 inch drift length about 15 kg liquid xenon Assumptions for GEANT4 Simulation 8 inches Top PMT Array Bottom PMT Array, meshes, PTFE

  28. Position resolution (σ) is less than 3 mm for 10 keV nuclear recoil events r [mm] Position reconstruction for XENON10: a 122 keV gamma event from side (data) XENON10: Expected Position Resolution S2 signal for each PMT from simulation, convoluted by S2 resolution and statistical fluctuation of photoelectrons in PMTs 10 keV nuclear recoils Reconstructed positions obtained by the minimum chisq method (same as for XENON3)

  29. 1st step A two-step (ΔZ~ 5 mm) event from XENON3 Most of the multiple scattering events can be easily identified by drift time separation (ΔZ > 2 mm). 2nd step S1 S2 Events with ΔZ < 2 mm can be identified by the chisq value from XY position reconstruction. Simulation for XENON10 n n ΔL LXe One neutron event with two steps (5 keVr each) separated by ΔL Events with two steps separated by more than 3 cm in XY can be efficiently identified. XENON10: Identify Multiple-step Events

  30. XENON10 TPC at Columbia Nevis Laboratory • Tested all systems prior to shipping to LNGS • 48 PMTs on top, 41 on bottom, 20 cm diameter, 15 cm drift length • 22 kg of Xe to fill the TPC. Active volume ~15 kg.

  31. XENON10 at Gran Sasso National Laboratory • Shield Construction started in XENON Box ( ex-LUNA) • Testing/Calibrating unshielded XENON10 (March-April 06) in neighboring Box XENON10

  32. LNGS: March 12, 2006

More Related