Dark Matter search with EDELWEISS and beyond Gilles

Dark Matter search with EDELWEISS and beyond Gilles Gerbier CEA Saclay – IRFU Rencontres de Moriond- VHEPU march 15 th 2013 European Underground Rare Event Calorimeter Array Expérience pour DEtecter Les Wimps En SIte Souterrain 1

The EDELWEISS collaboration 4800 mwe Karlsruhe • • • J Gascon/IPNL : spokesman CEA Saclay (IRFU and IRAMIS) CSNSM Orsay (CNRS/IN 2 P 3 + Univ. Paris Sud) IPN Lyon (CNRS/IN 2 P 3 + Univ. Lyon 1) Institut Néel Grenoble (CNRS/INP) LPN Marcoussis (CNRS) Karlsruhe Institute of Technology JINR Dubna Oxford University Sheffield University Laboratoire Souterrain de Modane - LSM (Fréjus tunnel) LSM 2

The EDELWEISS-II infrastructure Polyethylene shield Pb shield n n cryostat Innovative dilution cryogenic set-up (18 m. K) : q Can host up to 40 kg of detectors Shieldings : q Clean room + deradonized air 10 m. Bq/m 3 q Active muon veto (>98% coverage) q 50 -cm PE shield + 20 -cm lead shield 3 He detector Muon Veto Neutron counter n Other side monitoring detectors: q Radon detector down to few m. Bq/m 3 q He 3 neutron detector (thermal neutron monitoring inside shields) sensitivity ~10 -9 n/cm 2/s q Liquid scintillator neutron counter (study of muon induced neutrons) 3

The EDELWEISS-II infrastructure Polyethylene shield Pb shield n n cryostat Cryogenic installation (18 m. K) : q Can host up to 40 kg of detectors Shieldings : q Clean room + deradonized air 10 m. Bq/m 3 q Active muon veto (>98% coverage) q 50 -cm PE shield + 20 -cm lead shield 3 He detector Muon Veto Neutron counter n Other side monitoring detecetors: q Radon detector down to few m. Bq/m 3 q He 3 neutron detector (thermal neutron monitoring inside shields) sensitivity ~10 -9 n/cm 2/s q Liquid scintillator neutron counter (study of muon induced neutrons) 4

n n Detector principles : 3 parameters to isolate Old : Ge. NTD signal Germanium bolometers @ 17 m. K Ionization measurement @ few V/cm Heat measurement (NTD sensor) Discriminating variable between ER and NR « Q » = ionization/recoil energy All planar electrode Recent: ID 400 Fiducial annular electrodes VETO B electron recoils (ER) A: +4 V B: -1. 5 V Guard planar electrode Fiducial volume nuclear recoils (NR) C: -4 V Neutron calibration (S. Scorza Ph. D thesis) D: +1. 5 V VETO D n n = Ionization « VETO » = > « Surface/beta » identification : if non zero, reject event NB : idea first presented by CDMS group at LTD 5

n n Detector principles : 3 parameters to isolate Old : Ge. NT signal Germanium bolometers @ 17 m. K Ionization measurement @ few V/cm Heat measurement (NTD sensor) Discriminating variable= « Q » = ionization/recoil energy 6 x 104 210 Bi All planar 210 Po electrode 6 x 104 210 Pb Fiducial annular electrodes New : ID 400 A: +4 V electron recoils (ER) B: -1. 5 V 1 evt nuclear recoils (NR) Fiducial volume Guard planar electrode C: -4 V Neutron calibration (S. Scorza Ph. D thesis) D: +1. 5 V Surface identification = Ionization VETO If non zero, reject event n 6

EDELWEISS II limits (2011) and EDELWEISS -CDMS combined analysis n n n 10 ID detectors of 400 g operated during ~ 1 y CDMS has same target and same sensitivity Simple merger of data sets chosen prior to any analysis. n EDW II: 384 kg. d, [20200 ke. V], 5 evts n CDMS: ~379 kg. d, [~10 -100 ke. V], 4 evts => ~50% gain at high WIMP masses. NB : CDMS decides on an ID -inspired design for the electrodes of its future detectors. Phys. Rev. D 84, 011102 (2011). made with dmtools “WIMP safe” mass concept ! Check PDG “Dark Matter review” by Drees&Gerbier 7

Recent EDELWEISS low mass analysis n n Realization that, despite being tuned for MWIMP~100 Ge. V, EDELWEISS-II had significant efficiency down to 5 ke. V recoil Significant background rejection with ID electrodes down to low energy wth subset of data => significant improvement down to 7 Ge. V WIMP mass Resolutions are improving with new electronics (FWHM 900 e. V -> 650 e. V for ionization, 1. 25 -> <1 ke. V for heat) 500 e. V achieved in tests (HEMT R&D to go down to 300 e. V? ) PRD 86 (2012) 051701 R 25 octobre 2012 EDELWEISS-III report to CSIN 2 P 3 10 Ge. V WIMP – ID 3 EDW II LE

Searching for axions Detection/production by Primakov effect gag Solar axions -> +a --------->a+ -> f(E, t, a) Bragg diff Preliminary Single detector Edelweiss II Expected pattern f(E, t) for given orientation angle of crystal vs sun direction NB : electron recoils Other constraints on gae ma currently studied Ph. D Work of T de Boissiere 9

EDELWEISS-III : few 10 -9 pb sensitivity @ 60 Detectors Gev 40 FID 800 detectors 24 kg fiducial, n n installed 2013 (factor 15 wrt before) n 2 NTD sensors/detector n Current EDW-II setup : major upgrade n new cabling, cold electronics n new cryogenics (lower mphonic noise) n new internal PE shielding n replacement of thermal shields with lower activity Cu n => Expect lower thresholds, lower background ( and n), and redondancy n Program (1. 6 M€) funded : upgrade finished at 95 %, cool down on going (march 2013) with 15 detectors n Results by 2014 10

EDELWEISS III : new detectors FID 800 Fiducial mass ~640 g All annular electrodes • Fid mass *4 wrt to ID 400 • No NR event in calibration • Expected to be and indeed better than IDs ! FID 800(410 000 ) ID 400 (350 000 ) 11

EDELWEISS-III : improved 5 -15 Ge. V sensitivity n n Coverage of low-mass region with 4 FID detectors with 300 e. V FWHM resolutions (1200 kgd), 3 ke. V Er threshold thanks to new HEMT replacing JFET HEMT R&D ongoing 1 evt, 10 ke. V thresh 12 000 kg. j

EURECA Status 2013 n n n EDELWEISS+CRESST +others (19) CDR written Baseline : 2 phases: 150 kg then 1 t Choice of balance Ge / Ca. WO 4 to be optmised vs physics reach at time t Basic features q q q n n Favored site : LSM : deepest in Europe Large water active shield 7 m. K base temp , « scalable cryogenics » see P Camus Flexible design for different detectors Tower design : fully integrated, 7 mk 300 k see H Kraus No common official proposal submitted yet Strong will to make common project with S-CDMS 13

50 m LSM undergroun d lab extension New Last status jan 2013 Ø Excavation of the extension 2014 or 2015. Ø In operation in 2016/2017. Ø Detailed studies funded by Savoie departement and Rhone-Alpes Region Ø Agreement from Ministery and CNRS for the project Ø Funding in progress (85% already obtained CNRS, Region Rhone-Alpes, FEDER funds) Ø Technical discussion in progress New Actual France Italy

Summary , prospects 15