Present and Future Cryogenic Dark Matter Search in Europe

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Present and Future Cryogenic Dark Matter
Search inEurope
C R E S S T
ryogenic are vent earch with uperconducting hermom
eters
EURECA
EURECA

• Wolfgang Rau, Technische Universität München

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• 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)
...
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ILIASIntegrated 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,
  gt 1000 scientists

• Forum for discussion of future plans in Europe

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Overview

• CRESST
• Technique
• Status
• Next Future

• EDELWEISS
• Technique
• Status
• Next Future

• EURECA
• Idea
• Plans
• Status

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CRESST Technique

• Target CaWO4
• Cylindrical, ?/h 4 cm
• Mass 300 g
• Light output 1 (gs)

• Light detector
• 30 ? 30 ? 0.4 mm Si

• Thresholds
• Phonons 2 keV
• Light 20 eV
• 2 keVee
• Discrimination 12 keV

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CRESST Technique
Quenching

• Nuclear recoil less light than electron recoil!

• 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
?-band
?-band

• a-band between g- and n-band

• recoiling nuclei from a-decay

n-band
(O)
W-band
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CRESST Technique
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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)
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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. m-veto
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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)

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EDELWEISS - Technique
Target cyl. Germanium crystal, 320 g ? 7.0 cm,
height 20 mm (beveled)
Thermal NTD ( 20 mK)
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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 keV _at_ 10 keV
• 2 4 keV _at_ 122 keV
• Ion. 2 3 keV _at_ 122 keV

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EDELWEISS - Status
2003 Data (3 new detectors)

• 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
30100 keV)
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EDELWEISS - Status
NbSi sensors for athermal phonons
Outer electrode
NbSi meander

• 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

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EDELWEISS Next Future
Edelweiss II _at_ Modane (4800 m w.e.)

• 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)

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EDELWEISS Next Future

• Large new cryostat
• low activity
• inverse geometry
• up to 120 detectors

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EURECA
uropean nderground are vent search
with alorimeter rray
E U R E C A
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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

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EURECA Plans

• Discriminating cryogenic detector to reach a
  sensitivity ? 10-10 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

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EURECA Plans

• Structured in Working groups
• Detector Development
• Low Radioactivity
• Neutron Background, µ-veto and Shielding
• Cryogenics
• Cabling
• DAQ
• Underground site issues

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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 ???