DARWIN: DARk matter WImp search with Noble liquids

Transcription

1 DARWIN: DARk matter WImp search with Noble liquids darwin.physik.uzh.ch Laura Baudis University of Zurich (on behalf of the DARWIN Consortium) WONDER: Workshop on Next Dark Matter Experimental Researches at LNGS March 22-23,

2 Let s start with a dream... What if the two CDMS events are WIMPs?... What would XENON and WARP see? Assumptions: 110 kg x 1 year x 50% signal acceptance = kg days exposure (WARP-140) 30 kg x 200 days x 50% signal acceptance = kg days exposure (XENON100) Ar target; kev; kg days WARP events 5 10 events events events >50 events!"!*!"!) ;2/<-=>2<?/)!)"/@23?/$"""/@>!A-B. XENON100!!)/2C2D<. )!!"/2C2D<.!"!#"/2C2D<. #"!)"/2C2D<. E)"/2C2D<. / 10 6!"!( SI [pb] % 68% 90%! 78 /09:6!"!' %)+ (&+ %"+ 10 8!"!& Mass [GeV/c 2 ]!"!% /!"!!" #!" $,-../ # 6 Even then, we need much larger detectors for WIMP (astro)physics! 2

3 If nothing is seen in XENON idm likely excluded but new models will certainly appear... allowed by DAMA excluded by CDMS can be probed by XENON100 excluded by Xenon10 3

4 The XENON Dark Matter Search XENON/WARP/ArDM Evolution past current ( ) XENON R&D ongoing ( ) XENON Achieved (2007)!SI=8.8 x10-44 cm2 DARWIN XENON XENON100 XENON10 XENON1t future (before 2015) Projected (2010)!SI~2x10-45 cm2 XENON1T Goal:!SI <10-47 cm2 3 ArDM-1 ton WARP-140 WARP R&D WARP 2.3 l XENON100 and WARP-140 are under operation at LNGS 4

5 What is DARWIN? R&D and design study for a next-generation noble liquid facility in Europe Approved by ASPERA (AStroParticle ERAnet) in late 2009 (Proposal had been submitted in June 2009) From the proposal: The focus of the DARWIN proposal is to: coordinate the European groups active in this field, bringing in new and valuable expertise from closely related fields, towards the R&D and design study for a ton to multi-ton scale LAr and LXe dark matter search facility. The outcome of the collaborative work will be: a technical design report for the construction of a ton-scale LXe and multi-ton scale LAr experiment (the DARWIN facility), with the goal of reaching below cm 2 in sensitivity for the WIMP-nucleon cross section, which is three orders of magnitude below the current best results. 5

6 DARWIN Goals study liquid xenon AND liquid argon as WIMP targets make recommendation for technical design of facility in three years from now build on the added-value of uniting and coordinating the extensive, existing European expertise in liquid argon, liquid xenon and related technologies for astroparticle physics detectors within a global scenario Funding: provided by the national instruments of each participant ( virtual pot ) ASPERA News: Groups in Italy, France, the Netherlands and Switzerland will be funded to work on this project at a total cost of 633k. 6

7 Participating Institutions Participant no. Participant Organization Name Country 1. UZH (2 groups) University of Zurich Switzerland 2. Subatech (IN2P3) Laboratoire de Physique Subatomique et des Technologies Associees France 3. MPIK Max-Planck Institut für Kernphysik Germany 4. Muenster University of Muenster Germany 5. Karlsruhe University of Karlsruhe Germany 6. INFN (7 groups) Instituto Nazionale di Fisica Nucleare Italy (LNGS, L Aquila, Milano Bicocca, Napoli, Padova, Pavia, Torino) 7. Nikhef National Institute for Subatomic Physics Netherlands 8. IFJ PAN H. Niewodniczanski Institute of Nuclear Physics, PAN, Cracow Poland 9. US University of Silesia Poland 10. PWr Wroclaw University of Technology Poland 11. ETHZ ETH Zurich Switzerland Participant no. Participant Organization Name Country 1. Columbia Columbia University, New York USA 2. Princeton Princeton University USA 3. Rice Rice University USA 4. UCLA University of California, Los Angeles USA 7

8 DARWIN Institutions and Connections Groups from: ArDM and WARP for LAr XENON for LXe Europe: UZH, INFN, ETHZ, Subatech, MPIK, Münster, Nikhef, KIT, IFJPAN USA: Columbia, Princeton, Rice, UCLA 8

9 Components of DARWIN Optimization of detector design using performance extracted from real data from several existing LAr and LXe experiments, which we consider as prototypes for the larger scale facility Optimization of noble gas purification procedures, concerning traces of water and electronegative impurities, as well as radioactive isotopes Identification of material selection and process control needed for ultra-low background operation Definition of ancillary equipment requirements Exploration of optimal underground locations and a cost effective shielding configuration Study of the science impact of this technology The final goal is to deliver a technical design report on the largest scale facility feasible in three years (the DARWIN facility) as input for a coordinated proposal for construction and operation of such a detector underground. 9

10 Overall Physics Goal WIMP-nucleon, spin-independent cross section sensitivity of < cm 2 (below XENON1t) - 5 t and 10 t of fiducial mass for LXe and LAr (to be optimized by this study!) Assumptions - raw BG: 0.1 mdru in LXe, with 99.9% rejection of ERs, based on the S2/S1-ratio (factor 100 better than current XENON100 background of ~10 mdru) - raw BG: 0.45 dru in LAr, with 10 8 rejection of ERs, based on PSA and on the S2/S1-ratio (reduction of the 39 Ar rate by a factor 25 relative to atm Ar, corresp. to an activity of 40 mbq/kg for 39 Ar) - a NR acceptance of 50% for LXe and of 80% for LAr - thus, zero BG events (< 1 event) for the given exposure 10

11 Sensitivity comparison between LAr and LXe The relative sensitivity also depends on the energy threshold Rate [counts/kg day] Ar Xe xenon argon Recoil energy threshold [kev] Recoil threshold Ar [kev] Scaling Xe/Ar Recoil threshold Xe [kev] integrated rates for a 100 GeV WIMP mass scaling factor for integrated rate as a function of the energy thresholds in Ar/Xe 11

12 Complementarity between LAr and LXe ton years Xenon (50%) 10 ton years Argon (80%) 5 ton years Xenon (50%) + 10 ton years Argon (80%) SI [pb] 10 9 M = 50 GeV Ar: 119 events Xe: 348 events M = 100 GeV Ar: 141 events Xe: 310 events WIMP-nucleon cross section = 10-9 pb 1-sigma contours M = 200 GeV Ar: 102 events Xe: 191 events Mass [GeV/c 2 ] M = 500 GeV Ar: 51 events Xe: 85 events 12

13 DARWIN Location ULISSE (France) or Gran Sasso (Italy) GERDA 13

14 Structure of DARWIN Work package title Lead participant Management Detector infrastructure Light read-out Alternative charge read-out Electronics and DAQ Underground and shielding infrastructure Material screening and background modeling Science impact UZH, Switzerland (Laura Baudis) Münster, Germany (Christian Weinheimer) INFN, Italy (Giuliana Fiorillo) ETHZ, Switzerland (Andre Rubbia) Subatech, France (Dominique Thers) Rice, USA (Uwe Oberlack) MPIK, Germany (Hardy Simgen) Nikhef, Netherlands (Patrick Decowski) 14

15 Current phases of LAr and LXe TPCs Seen as prototypes and R&D for DARWIN WARP-140 ArDM-1t XENON-100 Many of the DARWIN decisions will be based on the outcome from these current experiments (WARP-140 and XENON-100 operate underground at LNGS) 15

16 Studies in progress Detector infrastructure: cryostat and inner TPC vessel cryogenic systems liquid handling and purification HV systems Light readout photo detectors UV light collection light yield of low-energy NRs in LAr/LXe Alternative charge readout large area thick GEMS gaseous photomultipliers Gridpix Electronics and DAQ low-noise electronics DAQ/trigger schemes computing centre Underground site and shielding LNGS investigations ULISSE investigations external backgrounds and shields coordination and supply of large amounts of liquid argon and xenon Material screening and backgrounds material screening cryogenic purification database and MC simulations 16

17 First DARWIN meeting: Zurich, January Many decisions taken Agreed on task group coordinators Agreed on information sharing among competing experiments Now the fun/work can start! 17

18 Time planning of DARWIN January 2010 First general meeting (UZH) WPs have been set up Website (public and internal) September 14-15, 2010 Second meeting (CERN or UZH) September 2011 Interim reports from WPs Third general meeting (Nikhef) Technical report September 2012 Fourth general meeting Final report Technical Design Study 18

19 DARWIN Website (darwin.physik.uzh.ch) 19

20 Rough time schedule after : R&D and Design Study 2013: Submission of LoI engineering studies : Construction and commissioning : Operation, physics data 20

21 6th Patras Workshop on Axions, WIMPs and WISPs: University of Zurich, axion-wimp.desy.de 21