Status of the EDELWEISS Dark Matter search KIT Institute Centre for Particle Nuclear and Physics Astroparticle Physics KIT University of the State of Baden-Wuerttemberg and National Research Center of the Helmholtz Association www.kit.edu
EDELWEISS @ Modane Underground Lab spokesperson: J. Gascon (IPNL) CEA Saclay (IRFU&IRAMIS) Paris-Orsay (CSNSM) IPNL Lyon Inst. Néel Grenoble KIT(IKP, EKP & IPE) JINR Dubna Oxford Univ. Sheffield Univ. Muon intensity, m -2 sr -1 y -1 5µ/m 2 /d (4800mwe) Modane 2 July 23, 2012 Klaus Eitel The EDELWEISS dark matter search
EDELWEISS-II experimental setup geometry as implemented in G4 MC cryogenic bolometer array 20 cm Pb shield (innermost 2 cm ancient Pb) 50 cm polyethylene 100 m 2 µ veto (48 plastic scint. modules) 1ton Gd-loaded liquid scint. for µ-induced Gd(n,g) not shown: Rn detector (~ mbq/m 3 ) 3 He n detector (~10-9 n therm /cm 2 /s) 3 July 23, 2012 Klaus Eitel The EDELWEISS dark matter search
EDELWEISS-II experimental setup 4 July 23, 2012 Klaus Eitel The EDELWEISS dark matter search
EDELWEISS-II detector technology Germanium bolometers Heat measurement (NTD sensor) E recoil E h (after NL correct.) Ionization measurement @ few V/cm discrimination between ER and NR Q = ionization/recoil energy Q(NR) ~ 1/3 Q(ER) 1 st generation GeNTD 320g all planar electrodes 2 nd generation ID400 * ID400g 5 July 23, 2012 Klaus Eitel The EDELWEISS dark matter search *measured via cosmogenic g lines
calibration with g/n-cources g calibrations with 133 Ba n calibrations with AmBe more than 350.000 g s g suppression factor 3x10-5 1 NR for every 30k g s (20-200keV) 90% CL signal region Q = 0.16 E r 0.18 from <10 to 200keV (detection efficiency below 20keV) P. Di Stefano et al., ApP14 (2001) 329 O. Martineau et al., NIMA 530 (2004) 426 A. Broniatowski et al., PLB 681 (2009) 305 6 July 23, 2012 Klaus Eitel The EDELWEISS dark matter search
EDW-II final result (2008+2009+2010) total exposure of 427kg.d 384kg.d in 90% NR band (WIMP RoI) fiducial mass 1.6kg 5 events observed (4 with E<22.5keV; 1 with E=172keV) 3 evts bg expected 20<E<100 kev no indication for a WIMP signal PLB702,5 (2011) 329 standard halo σ SI < 4.4 x 10-8 pb at 90%C.L. for M WIMP = 85 GeV/c 2 7 July 23, 2012 Klaus Eitel The EDELWEISS dark matter search
EDW-II results in s c vs. m c EDW (384kgd; [20-200keV], 5evts σ SI < 4.4 x 10-8 pb; M WIMP = 85 GeV/c 2 ) EDW-I EDW-II x20 improvement EDW-II 384 kgd E. Armengaud et al., PLB 702,5 (2011) 329 DAMA/LIBRA EPJ C56 (2008) CoGeNT PRL 106 (2011) CRESST II 2s arxiv:1109.0702 CRESST II 1s arxiv:1109.0702 Buchmüller et al, 2011 Bertone et al, 2011 8 July 23, 2012 Klaus Eitel The EDELWEISS dark matter search
EDW-II & CDMS comb. in s c vs. m c EDW (384kgd; [20-200keV], 5evts σ SI < 4.4 x 10-8 pb; M WIMP = 85 GeV/c 2 ) CDMS (~379kgd; [~10-100keV], 4 evts; σ SI <3.8 x 10-8 pb; M WIMP = 70 GeV/c 2 ) EDW + CDMS, combined analysis Phys Rev D 84 (2011) DAMA/LIBRA EPJ C56 (2008) CoGeNT PRL 106 (2011) CRESST II 2s arxiv:1109.0702 CRESST II 1s arxiv:1109.0702 CDMS Science 327, 1619 (2010) EDW-II PLB 702,5 (2011) 329 Buchmüller et al, 2011 Bertone et al, 2011 9 July 23, 2012 Klaus Eitel The EDELWEISS dark matter search
EDELWEISS-II low-e investigation arxiv:1207.1815v1 m(c)=10gev ID det s sensitive to NR s down to 5 kev new independent analysis < 20 kev selection of data set : keep 4 det s with sub-kev resolutions remove noisy periods χ 2 based cut fiducial cut on ionisation signal high trigger efficiency @ low energy : 78 % @ 5 kev, 90 % @ 6.3 kev best energy estimator for NR s at low energy : define "WIMP box" for each m c 10 July 23, 2012 Klaus Eitel The EDELWEISS dark matter search
EDW-II low mass results in s c vs. m c EDW (384kgd; [20-200keV], 5evts σ SI < 4.4 x 10-8 pb; M WIMP = 85 GeV/c 2 ) 113 kgd; [5-20keV], 1-3 evts σ SI < 1.0 x 10-5 pb; M WIMP = 10 GeV/c 2 ) EDW-II PLB 702,5 (2011) 329 + arxiv:1207.1815 EDW-II & CDMS PRD84 (2011) DAMA/LIBRA EPJ C56 (2008) CoGeNT PRL 106 (2011) CRESST II 2s arxiv:1109.0702 CRESST II 1s arxiv:1109.0702 CDMS Science 327, 1619 (2010) + Low E, PRL 106 (2011) XENON100 PRL 107 (2011) Buchmüller et al, 2011 Bertone et al, 2011 11 July 23, 2012 Klaus Eitel The EDELWEISS dark matter search
EDW-II low mass results in s c vs. m c EDW (384kgd; [20-200keV], 5evts σ SI < 4.4 x 10-8 pb; M WIMP = 85 GeV/c 2 ) 113 kgd; [5-20keV], 1-3 evts σ SI < 1.0 x 10-5 pb; M WIMP = 10 GeV/c 2 ) 12 July 23, 2012 Klaus Eitel The EDELWEISS dark matter search EDW-II PLB 702,5 (2011) 329 + arxiv:1207.1815 EDW-II & CDMS PRD84 (2011) DAMA/LIBRA EPJ C56 (2008) CoGeNT PRL 106 (2011) CRESST II 2s arxiv:1109.0702 CRESST II 1s arxiv:1109.0702 CDMS Science 327, 1619 (2010) + Low E, PRL 106 (2011) XENON100 PRL 107 (2011) XENON100 225days 34kg Buchmüller et al, 2011 Bertone et al, 2011
EDW-III: next generation of detectors 2. generation ID detectors with lateral planar electrodes 400g cylindrical ID detector 6 NR evts in 350.000 gamma calib evts 13 July 23, 2012 Klaus Eitel The EDELWEISS dark matter search
ionization yield 3. generation: FID detectors with rings on all surfaces NTD1 A B A B A B A B A B A B NTD2 EDW-III: next generation of detectors 75% fiducial C D C D C D C D C D C D A B A B D C D C g-calibration with 133 Ba (411663g s) preliminary 800g total mass ~600g fid. mass no NR evts in >400.000 g calib evts 14 July 23, 2012 Klaus Eitel The EDELWEISS dark matter search recoil energy (kev)
EDELWEISS-III (2012 upgrade) major upgrade of internal cryostat new arrangement of Ge bolometers new Cu mounting & thermal shields g bgd new internal PE shield @ 1K n bgd increase target mass 40 detectors à 800g 2 NTD, 4 (6) electrodes [2 «fiducial» volumes] 218 ultrasonic bondings per detector Background (20 200 kev) EDW-2 (evt / kg.d) EDW-3 (evt / kg.d) gamma rate 82 14 44 ambient neutrons (2.6-8.1) 10-3 mainly due to cables and connectors (0.8 1.9) 10-4 15 July 23, 2012 Klaus Eitel The EDELWEISS dark matter search
EDELWEISS-III (2012 upgrade) upgrade of electronics & cabling 100K 300K 1K Optical In/Out BBv1 or BBv2 Digital Board + fast readout board mezzanine DC-DC converters Analog board: 6 Low noise voltage amplifiers & DAC board new cables 300K-100K-1K-10mK FET boxes AD boxes w/ 100kHz/40MHz sampling new front-end electronics <1 kev FWHM baseline resolution upgrade of DAQ & data structure EDELWEISS PLB 681 (2009) >240 ch s in 1 crate; fast trigger for ionisaton A. Cox et al., NIM A684 (2012) 16 July 23, 2012 Klaus Eitel The EDELWEISS dark matter search
Events / day EDW investigations on µ-induced neutrons µ veto.and. bolometers 1504 kg.d Gd-loaded scint. Neutron counter µ veto.and. Gd(n,g) AstropartPhys 34 (2010) 97 before vetoing Background (20 200 kev) EDW-2 (evt / kg.d) EDW-3 (evt / kg.d) gamma rate 82 14 44 GEANT4 (no scaling!) Measured excess (793 live days, 272 hits) ambient n s (2.6-8.1) 10-3 (0.8 1.9) 10-4 µ-induced n s < 1 10-3 < 4 10-4 # of secondaries within T DAQ 17 July 23, 2012 Klaus Eitel The EDELWEISS dark matter search
EDELWEISS-III goal for 2013 <1 evt total background estimated for 3000kg.d eff. exposure EDW-II PLB 702,5 (2011) 329 + arxiv:1207.1815 EDW-III 24kg(fid) 6 months DAMA/LIBRA EPJ C56 (2008) CoGeNT PRL 106 (2011) CRESST II 2s arxiv:1109.0702 CRESST II 1s arxiv:1109.0702 CDMS Science 327, 1619 (2010) + Low E, PRL 106 (2011) EDW-3 projected 3000 kg.d 24kg fid. mass x 125days XENON100 PRL 107 (2011) XENON100 225days 34kg Buchmüller et al, 2011 Bertone et al, 2011 18 July 23, 2012 Klaus Eitel The EDELWEISS dark matter search
beyond EDELWEISS-III: EURECA EURECA goal: 10-10 -10-11 pb, 150kg 1000kg, multi-target, bgd ~ 10-3 evts/(kg.y) EDW, CRESST, ROSEBUD, + others coordinated cooperation with SuperCDMS (1 st joint meeting Oct 7, 2011) CDR in summer 2012 facility type (DM, 0nbb,...) part of European ASPERA roadmap cryostat in water Cerenkov detector towers multi-target det s 19 July 23, 2012 Klaus Eitel The EDELWEISS dark matter search
Conclusions EDW-I EDW-II factor 20 improvement EDW-II: 10 ID Ge bolometers m det = 400g; m fid = 160g 1.6kg fid 20-200keV: 5 evts, 5.1 bgd (dominated by ambient n s) 5-20keV: 1-3 evts, <3 bgd (1.7 n s + 1.2 g s) EDW-III: 40 FID Ge bolometers m det = 800g; m fid = 600g 24kg fid upgrade of inner cryostat, new internal shield upgrade of cabling and electronics reduction of bgd (gammas: 2-6; neutrons >10) EDW-III 3000kgd fid exposure in 6 months (no bgd expected) EDW-III detector technology ready for 1-ton cryogenic array 20 July 23, 2012 Klaus Eitel The EDELWEISS dark matter search