Present and Future Cryogenic Dark Matter Search in Europe Wolfgang Rau, Technische Universität München CRESSTCRESST EURECA ryogenic are vent earch with uperconducting hermometers

Wolfgang Rau, TUMFuture Direct Detection, Chicago 12/04 2 CRESST Max-Planck-Institut for physics (Munich) Technical University Munich University of Oxford Laboratori Nazionali del Gran Sasso University of Tübingen University of Warwick EDELWEISS CEA-Saclay DAPNIA/DRECAM CRTBT Grenoble CSNSM Orsay FZK/Univ. Karlsruhe IAP Paris IPN Lyon Laboratoire Souterrain de Modane EURECA + CERN + MPIK (Heidelberg) +...

Wolfgang Rau, TUMFuture Direct Detection, Chicago 12/04 3 ILIAS Integrated Large Infrastructures for Astroparticle Science Financed by EU Infrastructure for astroparticle physics in Europe (not complete, but a good start) Contains different structures: –Networks (Dark Matter, Double Beta, Underground Science, Gravitational Waves, Theory) –Joint Research Activities (Double Beta, Low Background, Gravitational Waves) –Transnational Access (Underground laboratories) 12 Countries, 20 Contractors / ~140 Institutes, > 1000 scientists Forum for discussion of future plans in Europe

Wolfgang Rau, TUMFuture Direct Detection, Chicago 12/04 4 Overview CRESST –Technique –Status –Next Future EDELWEISS –Technique –Status –Next Future EURECA –Idea –Plans –Status

Wolfgang Rau, TUMFuture Direct Detection, Chicago 12/04 5 CRESST – Technique W-TES: (T c = 6-10 mK) Heater for stabilization (DC) and calibration (test pulses) 6  8 mm² Al contact W Au heater Target: CaWO 4 Cylindrical,  /h:4 cm Mass:300 g Light output:~1 % (  ’s) Thresholds Phonons: 2 keV Light:20 eV ~2 keVee Discrimination:12 keV Light detector 30  30  0.4 mm Si

Wolfgang Rau, TUMFuture Direct Detection, Chicago 12/04 6 CRESST – Technique W-band  -band Recoil energy Light energy Quenching Different light yield for different nuclei (O, Ca, W)? Two experiments to measure Quenching (so far room temp.): Neutron scattering Ion beam Both indicate: less light for heavy nuclei Additional support from data Reflector CaWO 4  -band between  - and n-band recoiling nuclei from  -decay  -band n-band Nuclear recoil less light than electron recoil! (O)

Wolfgang Rau, TUMFuture Direct Detection, Chicago 12/04 7 CRESST – Technique 3600 m w.e. Gran Sasso

Wolfgang Rau, TUMFuture Direct Detection, Chicago 12/04 8 CRESST – Status Spring 2004: 2 months run with 2 detectors  sensitivity limited by neutrons  if high QF applies for WIMP recoils: results comparable to EDELWEISS (10 -6 pb) Light yield Run 28, Daisy Energy in Phonon Channel [keV] Light yield Energy in Phonon Channel [keV] Run 28, Julia (bad light resolution)

Wolfgang Rau, TUMFuture Direct Detection, Chicago 12/04 9 CRESST – Status Since April 2004: upgrade Install neutron moderator (30-50 cm PE, 11 t); µ-veto Increase number of readout channels (4  66) Enlarge target mass (600 g  10 kg) Shielded cryostat PE neutron moderator Plastic scintill.  -veto 66 SQUIDs on He-flange

Wolfgang Rau, TUMFuture Direct Detection, Chicago 12/04 10 CRESST – Next Future Finish major work by beginning of 2005 Restart with few detectors Install new detector holder late spring Increase target mass to 10 kg within 2005 Situation in Gran Sasso not clear (major construction work expected – influence on CRESST so far unknown)

Wolfgang Rau, TUMFuture Direct Detection, Chicago 12/04 11 EDELWEISS - Technique Target: cyl. Germanium crystal, 320 g  7.0 cm, height 20 mm (beveled) Ionization: Inner disk / outer ring (“guard”) with  -Si /  -Ge Thermal: NTD (~ 20 mK)

Wolfgang Rau, TUMFuture Direct Detection, Chicago 12/04 12 EDELWEISS - Technique Thresholds Heat: 0.4 – 2 keV Ionization: 1.1 – 1.5 keV Analysis Ion. trigger:20 – 30 keV Phon. trig.:15 keV Resolution Heat:0.6 – 2 10 keV 2 – keV Ion.:2 – keV

Wolfgang Rau, TUMFuture Direct Detection, Chicago 12/04 13 EDELWEISS - Status Ion. trigger 20 kg d Thr: 20/30 keV 3 events Phonon trigger 22 kg d Thr: 15 keV 18 events 1 coinc. (n-n) 2000 – 2003: 62 kg d, 40 events (only 3 for 30–100 keV) 2003 Data (3 new detectors)

Wolfgang Rau, TUMFuture Direct Detection, Chicago 12/04 14 EDELWEISS - Status NbSi sensors for athermal phonons NbSi: metal-isolator transition (high R) 2 surfaces covered (ionization + heat sensors) Two-component signal: -Thermal (energy) -Athermal (surface discrimination ) Successful test with 200 g modules in EW I: -90 % rejection -50 % efficiency Outer electrodeNbSi meander

Wolfgang Rau, TUMFuture Direct Detection, Chicago 12/04 15 EDELWEISS – Next Future Aim for sensitivity improvement  100 Installation started 04/04 – expected to finish summer 05 1st phase: 21 NTD detectors (320 g), 7 NbSi detectors (400 g) Edelweiss Modane (4800 m w.e.)

Wolfgang Rau, TUMFuture Direct Detection, Chicago 12/04 16 EDELWEISS – Next Future Large new cryostat –low activity –inverse geometry –up to 120 detectors Improved shielding –20 cm lead –50 cm PE –Muon veto

Wolfgang Rau, TUMFuture Direct Detection, Chicago 12/04 17 EURECA uropean nderground are vent search with alorimeter rray EURECAEURECA

Wolfgang Rau, TUMFuture Direct Detection, Chicago 12/04 18 EURECA – Idea Next generation DM search to explore most of SUSY parameter space Cryogenic experiments very promising Target mass in the 1 ton range Different targets (WIMP signature) Collect European competence

Wolfgang Rau, TUMFuture Direct Detection, Chicago 12/04 19 EURECA – Plans Discriminating cryogenic detector to reach a sensitivity  pb for coherent interaction Better sensitivity for spin-dependent interaction Design study to investigate requirements and technical challenges: –Detector development (larger modules, better discrimination, other targets) –Optimal shielding strategies –Background reduction (handling/cleaning) and modeling (Monte Carlo simulations) –Cryogenics, electronics, cabling, DAQ

Wolfgang Rau, TUMFuture Direct Detection, Chicago 12/04 20 EURECA – Plans Structured in Working groups: Detector Development Low Radioactivity Neutron Background, µ-veto and Shielding Cryogenics Cabling DAQ Underground site issues  ILIAS

Wolfgang Rau, TUMFuture Direct Detection, Chicago 12/04 21 EURECA – Status Letter of Intent to ApPEC summer 2004 Start proposal process September 2004 Present Proposal to ApPEC January 2005 Present Proposal to Funding Agencies Start work 2005/06 ???