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DRIFT II & DTM recent work 2010/11

DRIFT II & DTM recent work 2010/11. AIM: Directional Detection of WIMP Dark Matter - Identify a Galactic Signal. UK: Sheffield, Edinburgh, STFC. US: Occidental, UNM, CSU. New publications including world’s best limit with direction sensitivity (unblind).

dorian-caldwell
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DRIFT II & DTM recent work 2010/11

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  1. DRIFT II & DTM recent work 2010/11 AIM: Directional Detection of WIMP Dark Matter - Identify a Galactic Signal UK: Sheffield, Edinburgh, STFC US: Occidental, UNM, CSU • New publications including world’s best limit with direction sensitivity (unblind) N.J.C. Spooner et al. Astroparticle Physics 34 (2010) 284 E. Daw et al, sub Astroparticle Physics (2011) - arXiv:1012.5796 47 day run with CS2/CF4 UK work • built and installed new gas system for CF4 (SI sensitivity) • Built and installed upgrade to DAQ • Key analysis of low background and radon reduction and emanation system • Run all operations Only DRIFT here also has directional sensitivity next best directional is ~x1000 worse Underway now • New blind analysis with x15 improved background to be released soon

  2. DRIFT IId new upgrade success at Boulby 20 μm wire cathode 0.9 μm film cathode Background Background IWS-RMST (μS) Neutron Neutron anode F recoil energy (keV) anode F recoil energy (keV) • New upgrade to thin (alpha transparent) cathode shown to suppress background by another x15-30 Plot shows neutron calibration and background from radon induced recoils before and after replacement of central cathode New blind analysis imminent to set improved limit/sensitivity

  3. Directional DM Opportunities at Boulby Context • Five non-directional DM experiments have “backgrounds” above expectation - the directional sensitivity can provide a clearer signal identification and determine galactic origins - the UK can have a leading role • The directional field is rapidly growing, now 5 groups: DRIFT, MIMAC, NEWAGE, DM-TPC, D3 worldwide (~150 scientists). We started the CYGNUS international cooperation (Boulby2007, MIT2009, Aussois2011) Workpackages: (1) gas, (2) background, (3) directionality, (4) halo physics • Funding for the Boulby Palmer Laboratory secured for 3 years under STFC environment programme even though ZEPLIN has gone - a big opportunity for a re-newed UK effort • NSF supports continuation at Boulby • Mine company CPL supports new excavation for scale-up Proceed to scale-up at Boulby to 24 m3 called DTM (DRIFT III module) The only UK-based particle physics experiment

  4. Scale-up Design for DTM (DRIFT III Module) of 24m3 • US-UK design well advanced • 24 m3 4 kg target • 3D readout with track sense • Modular to allow ton-scale • z-fiducialisation by +ve ion detection and thin cathode • C, S, F targets to include spin dependent sensitivity UK current contributions: gas system, radon/background reduction, slow control, shield, site, analysis and data Field cage Field cage Sensitivity Estimates (SD) anode cathode current limits DRIFT IId - 10 day run, zero background prediction DRIFT IId - 2.4 m3-years, zero background prediction DTM - 1 year run 4 kg.yr electronics

  5. DTM Extension 6m 6m 6m DTM Boulby Location & CPL Cooperation • Site for first DRIFT III module identified at Boulby • CPL willing to excavate for DTM with in-kind contribution • Only simple infrastructure needed scale drawing 40m Current Palmer Lab back entrance to roads

  6. Main messages Despite the finances and thanks to strong support from the US and mine company DRIFTII is doing well though increasingly difficult for UK groups. We previously demonstrated directional capability in 1 m3 focussing more recently on background reduction and use of F target. This has succeed, allowing us to produce a competitive SD limit with no compromise on the directional sensitivity. This is unique. Our recent upgrade to a thin cathode to supress radon induced recoils has shown we can reduce this dominant background by x15. A new fully blind analysis based on this new data will be released in the summer for a new limit. The technique to z-fiducialise by +ve ion detection has been proved by UNM and will be installed next, plus a further upgrade of the cathode. The UK has recently been responsible for a complete upgrade of the DAQ. This will allow improved 3D reconstruction. There is world-wide growth of interest, partly stimulated by several above-background results in non-directional detectors. There are now 5 serious directional groups with ~150 people (incl theorists) e.g. MIMAC is about to deploy in Modane., DM-TPC is in WIPP and NEWAGR in Kamioka. We have grouped together at a semi-formal level, called DARK-CYGNUS and developed joint work-packages. There is enthusiasm and an opportunity to go to the next step now at Boulby, with the site at least secured for 3 years and mine company CPL interested to help. The aim is to build DTM - 24m3. There is currently no direct STFC support.

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