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DRIFT-III Proposal for a Large Scale Directional Dark Matter detector @ SNOLAB

DRIFT-III Proposal for a Large Scale Directional Dark Matter detector @ SNOLAB Sean Paling - Sheffield University For the DRIFT Collaboration: Occidental College, University of New Mexico, Boston University, Imperial College, RAL, Sheffield, Edinburgh (UK Dark Matter Collaboration - UKDMC).

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DRIFT-III Proposal for a Large Scale Directional Dark Matter detector @ SNOLAB

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  1. DRIFT-III Proposal for a Large Scale Directional Dark Matter detector @ SNOLAB Sean Paling - Sheffield University For the DRIFT Collaboration: Occidental College, University of New Mexico, Boston University, Imperial College, RAL, Sheffield, Edinburgh (UK Dark Matter Collaboration- UKDMC)

  2. DRIFT-III: Phase ONE Proposal: House phase ONE of DRIFT-III @ SNOLAB An array of 10 low-pressure Negative Ion DRIFT TPC modules (≤10 kg target mass, 10-8pb raw sensitivity) Will discuss: • Motivation & concept • Progress so far (DI/DII) • DIII-phase ONE details & requirements DRIFT-II@Boulbymine Extension of current DRIFT-II programme @ Boulby mine. 1st step & test-bed for scale-up to DRIFT-III - a 100+ module 100kg directional detector 10-9pb (raw) and 10-7/8 (directional) sensitivity DRIFT-III phase ONE

  3. WIMP Wind 12:00h 42o 0:00h Galactic WIMP Halo To provide THEmost powerful signature of the existence WIMPs in the galaxy - through unambiguous measurement of the WIMP wind. Why a Directional Detector?

  4. WIMP arrival distributions Different models produce different WIMP arrival directions/velocities Spherical Isothermal Clumps Moore et al..... Sagittarius Stream - Freese et al. Tidal Stream Logarithmic Ellipsoidal Tidal disruption streams Stiff et al.. Freese, Gondolo et al. Sun’s influence Fu-sin Ling et al. Sikivie, Wick et al (B. Morgan, A. Green, N. Spooner - Astro-ph/040804) Later - WIMP Halo studies • No longer just the simple spherical, Isothermal Halo... • velocity space anisotropy • bulk rotation • substructure, clumps • triaxality, oblate vs. prolate • late accreted sub-halos • sub-structure on sub-pc scales • spikes and caustics Study the structure & dynamics of the Dark Matter Halo

  5. Scattered WIMP CS2 Recoil Atom Drift direction MWPC Readout Plane Cathode Electric Field The DRIFT Concept How to build a directional detector? Problem: In solid or liquid targets <100keV recoil tracks ~ 1-100nm long DRIFT: A Low Pressure Negative Ion Drift TPC (NITPC) Low Pressure TPC: • Low pressure target extends range of WIMP nuclear recoils to a few mm. • 3D reconstruction possible by combining 2D readout with signal timing analysis. Negative Ion DRIFT: • Electron capture by electronegative gas reduces track diffusion. • Diffusion of <0.5mm at 0.5m drift length (1000v/cm) (Rediscovered by Martoff - Temple)

  6. Alphas Nuclear Recoils Gammas The DRIFT Concept DRIFT Background discrimination • Based on signal ENERGY and RANGE. • Nuclear recoils have a higher dE/dx than background electrons or alphas. Gamma discrimination of >106 so far demonstrated. (Snowden-Ifft et al. NIM A 498 (2003), & - Kirkpatrick et al, in preparation) • Little / no gamma shielding! • Competitive as hi-sensitivity, • limit-setting detector.

  7. Adding Xe potentially… • Increases sensitivity by factor ≤5 • Greatly assists verification of +ve wimp signal (proprotion of Xe to C/S recoils) (P.F.Smith et al, Astroparticle Phys 22, 2005) How Sensitive? Xe Enhancement: (50% Xe/CS2) (10keV threshold) 167g Target (1m3, 40 Torr) (20 keV threshold) Scale up: 100kg (10keV theshold) (Preliminary) 36,500 kg.d no events 36,500 kg.d no events 61 kg.d no events Single DII module 1 year 100kg DIII 1 year 50% Xe:CS2 100kg DIII 1 year

  8. IF recoil sense known10-20 events needed, if unknown 100-400 events needed - to reject isotropy at 95% confidence in 95% of experiments. What about ‘Halo’ Sensitivity? How many WIMPs to verify directional Halo signature? (B. Morgan, A. Green, N. Spooner - Astro-ph/040804, also: B. Morgan, A. Green - in preparation). 40 keV S recoil in 40 Torr CS2 (SRIM) • Simulations for realistic (advanced) • NITPC Detectors… • 40 Torr CS2, 1 kVcm-1 drift field • 200 mm resolution, 10 cm drift • SRIM2003 - recoil scattering and diffusion Results depend on: Halo Model Reconstruction accuracy (Can we tell the ‘sense’ of the track? - Head or Tail?) ‘Halo sensitivity’ is between factor 10 & 100 behind raw detection sensitivity (depending on halo model and detector technology).

  9. Halo sensitivity 10-5 DAMA Detection sensitivity 10-6 Edel I, CDMS I, Zep I, DRIFT-II.. 2003 Next Steps: Galactic confirmation - directionality halo studies 10-7 Edel II, CDMS II, Zep II, DRIFT-II.. DRIFT-III scale-ups 10-8 Phase ONE 2006 Pb DRIFT-III 10-9 1 ton ~1 event/100kg/year 2010 10-10 1000 GeV 100 GeV 100 ton ~1 event/10ton/year 10-11 2020 10-12 100kg DRIFT & the World DM Search mssm Roszkowski et al. No signal Signal found

  10. 2000 2001 2002 2003 2004 2005 2006 2007 1997-2002: Concept development, gas tests, simulations 1ft3 NITPC prototype studies. Surf commission - Sheffield DRIFT-I: 1m3 (167g) NITPC. Development, installation/operation @ Boulby DRIFT-II: 3(+) 1m3 (0.5-2kg) NITPC Development, installation/ operation @ Boulby Scale-up R&D: Simulations, readout, reconstruction, cost, engineering. Install (Jan 02)) Boulby Mine (UK) 2805 mwe Operation Surf commission - Oxy Install (May 05)) Operation DRIFT-II, Phase ONE (10 modules): Installation 2007/8 The DRIFT Programme

  11. DRIFT-I • 1m3 Dual Negative Ion DRIFT TPC • 1.4m3 vac vessel - 40 Torr CS2 (167g fiducial) • Back-to-back 0.5m3 DRIFT regions. • MPWC readout (512 20m anodes, 2mm pitch) • DAQ: 2512 chan 1S sampling. Installation 2001/2, Operation 20022004 DRIFT I: 1st large-scale DRIFT detector. DRIFT-I @ Boulby MWPC layout UKDMC, Occidental, Temple

  12. DRIFT-I • Outcomes • Demonstration of safe, stable, long-term operation UG . • Demonstration of event characterisation/discrimination. • Measurement of rock neutrons • Early verification of high gamma discrimination (>106) • Alner et al, NIMA, 535 (2004), • Kirkpatrick et al (2005) - in preparation • Status • Some technical/engineering difficulties (DAQ, MWPCs, Fatigue). •  Moved on to apply numerous design/engineering lessons learned • to DRIFT-II

  13. Aim: Advanced, multi-module (3+) detector with sensitivity of ~10-7pb. Using lessons from DI and R&D. DRIFT-IIa @ Boulby • Basic Design 1st step toward large scale multi-module upgrade • 3(+) 1m3 fiducial vol, NITPCs • Back-to-back drift vols, dual MWPC readout • Vertical planes, Warp adjust strongback MWPCs • Improved (3d) track reconstruction (anode, grid and z-drift) (resolution: 2mm(x), 0.1mm(y), 0.1mm (Z)) • Low noise / cost 0.5S sampling (grouped) DAQ • Improved vessel design (<10-8T.L.s-1) . • Improved gas system (varied gas pressure & mixtures) Robust, simple, reproducible & cost-reduced… DRIFT II (Factor 5 cost-reduction per module vs. DRIFT-I)

  14. DIIa - Construction & Commissioning November 2004 MWPCs, 512 20um anode wires: lucite frame with warp-adjust bars Inner detector stack Side-oriented back-to-back field cages with rigid Cu piping. 1.5m3 cubed stainless steel vacuum vessel (UK/USA) Grid amplification & grouping, prior testing.

  15. ZEPLIN - III >2.0m >2.0m Late 2004 Boulby Mine - The JIF Area Boulby Mine (UK) 2805 mwe Dark Matter ‘JIF’ Area Stub A Stub B Low BG Lab DRIFT-II Data acquisition system DRIFT-I Exhaust CS2 sensor ZEPLIN-II Detectors / Vacuum Chambers 3 2 1 gas systems, fume hood & extraction hose ZEPLIN - II DRIFT-I Lab Entrance corridor CS2 sensor Mess ~100m Gas/fire sensor control >1500m2 floor space (5m3.5m cross section) 2T full XY crane Communications, workshop Storage, clean room

  16. DIIa - fully installed, underground commissioning complete. • Gas / vacuum system tests. • Neutron, alpha, gamma/X-ray calibrations, directed neutrons (directionality). • Demonstrated long term operation & stability (5 weeks continuous running - for pre-shielded data). Next steps: - erect 40g.cm-2 neutron shielding (Polypropylene pellets in wooden support structure). (Completion this week - followed by start of running shielded) Construction/installation of modules b & c underway (full operation early 2006) DRIFT II Status (July-Aug 05) DIIa DIIb

  17. Why multi-module? • Site/technology constraints on size. • Allows staged construction/installation • Minimises down time • Module comparisons (diagnostic. array) • Variable configuration/siting. • Cost (etc) benefits of mass production. DRIFT-III Concept: • • Mass Production of 100(+) advanced, • robust, reliable, stable & safe, NITPC • modules. • • 100kg total fiducial mass, 10-9pb (10-7/8pb) • raw (directional) sensitivity (per yr). • • High resolution 3d readout, high pressure • (≤240 Torr) CS2 (or other). • Time-scale: Installation 2010? DRIFT-III This proposal Phase ONE (2006/7): 1st 10 detectors: 101m3 (fiducial), 40-240Torr (up to 10kg), 10-8pb raw sensitivity per yr. - forerunner to full extension of array. Towards DRIFT-III (100kg)

  18. Scale up R&D DRIFT-III R&D Reduce Backgrounds Optimize design / performance Minimize costs Specific technical R&D issues: 10(+) better directionality ‘head-tail’ discrimination (Bragg curve of recoiling ions? - Boston, UNM, UKDMC) Improved resolution readout. higher pressure - lower volume (Micromegas? GEMs? <50µm? - UKDMC, UNM) Improved track resolution, BG rejection. ‘Z fiducialisation’ (Cathode readout, diffusion - Oxy) Increased sensitivity, WIMP signal verification Alternative gases/mixture (Xe:CS2 mixture, CF4, etc - UKDMC/Oxy)

  19. Costs AIM: further reduce costs (through MASS PRODUCTION) to ~£20K (<$40) per unit inc. shielding If successful: <£2-10M (material/equipment) for 100kg. (~£0.2M for DRIFTIII-phase ONE)

  20. DRIFT-III needs greater depth to avoid costly muon-veto... @ SNOLAB (~6010mwe) n <1 Background reduction DRIFT-III Neutron Background Simulations GEANT4 (FLUKA & SOURCES) M. J. Carson et al. Astropart. Phys. 21 (2004) J. Davies et.al, NIMA, 546 (2005) Neutron (excluding muon-induced) For 100kg DRIFT @ Boulby Muon-induced Neutrons @ Boulby ( 2805 MWE) n >50

  21. Later scale-up: DRIFT-III (100+ detectors) Is size a problem long term? - Not necessarily: Size dependent on technology and location. e.g: in a large hall - stacked design, ~2000(+)m3 needed. e.g: In a ‘corridor’ - linear design : ~300(+)m of tunnel with 3.3m cross section… D-III could be split - more than one lab or UG site! NEW areas dug? - cost of excavation @ Boulby estimated >£1.M for 200m tunnel DRIFT-III phase ONE Size/arrangement dependent on location. 10  1m3 (fiducial)detectors (1.5m3 vessels), 50-60gcm-2 CH shielding, Need ≤30m of tunnel - 3.3m cross section (inc gas system, staging, storage & control) Size/space needed?

  22. Large Experimental Space Emergency Egress <30m Smaller Drifts Utility Area DIII Phase ONE 2 banks of 5 shielded detectors, gas system, DAQ,storage/staging 30m (3.3m2 cross sec) SNOLAB Ladder Labs…

  23. Proven safety record: No incidents in over 3 years operation @ Boulby Fully compliant with stringent Boulby safety system (PIP). Comprehensive risk assessments, procedures, change control documentation produced & maintained. DII safety documentation Other Facility Issues By necessity for scale up (mass production / installation) DRIFT- III phase ONE = robust, stable, safe, low maintenance, low cost - low demand on infrastructure/services General facilities: • Transportation:10 detectors + vessels, support apparatus, 100T PP shielding. • 2T lifting capacity (crane/forks?) • ≤ 30m2 staging/material storage space. Moderate class clean room (<class 2000). • Power: 500W single phase per module (>10kW for 10 & support apparatus). • Light use of mechanical & electrical workshop • Moderate temperature stability (+/-2C) Special requirements: • No cryogenics, vibration control, laser & optics, water purifcation. • Radioactive sources: Small (C) neutron. gamma & Alpha calibration sources. • Gases/Chemicals: Reduced CS2 quantity (sealed?). <15kg max. Health & Safety: Main issues = CS2 target gas (100kg) and use of High Voltage.

  24. Funding & Schedule DRIFT III phase ONE Funding: • Estimated total cost. ≤£1M (eqpt, staff, R&D) - over 3-4 years. • DRIFT program currently funded by NSF (in US) & PPARC (in UK). European funding also becoming available. • Specific applications for DIII phase ONE will be submitted 2005/2006 Schedule: 2005-7 DRIFT-II operation and scale-up R&D 2006/7 Design development / review. Site preparation, 2007/8 Staged construction, installation, operation. 2008+ Full operation, evaluation/R&D for upgrade to DIII 2010? Staged installation of DRIFT-III.

  25. Summary A directional detector could provide THE most powerful signature for existence of WIMPs in the galaxy - DRIFT is far ahead of the pack in developing directional detector technology. Now looking towards extending current programme to produce a large-scale 100kg detector (DRIFT-III) - giving 10-9pb (raw) sensitivity per year. Complement & compete with next non-directional detectors. Phase ONE @ SNOLAB? - a REALISTIC 1st step in this upgrade: 10 modules with mass of up to 10kg and raw detection sensitivity 10-8pb per year. Forerunner to later upgrade. DRIFT Technology = low maintenance, low impact on facility requirements. Low risk - proven record of safety & delivery at Boulby mine.

  26. Join us? DRIFT-III Proposal for a Large Scale Directional Dark Matter detector @ SNOLAB Sean Paling - Sheffield University For the DRIFT Collaboration: Occidental College, University of New Mexico, Boston University, Imperial College, RAL, Sheffield, Edinburgh (UK Dark Matter Collaboration- UKDMC)

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