View
215
Download
0
Tags:
Embed Size (px)
Citation preview
Present and Future Cryogenic Dark Matter Search in
Europe
Wolfgang Rau, Technische Universität München
CRESST
EURECAEURECA
ryogenicareventearch withuperconductinghermometers
Wolfgang Rau, TUM Future 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, TUM Future Direct Detection, Chicago 12/04 3
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, > 1000 scientists
• Forum for discussion of future plans in Europe
Wolfgang Rau, TUM Future Direct Detection, Chicago 12/04 4
Overview
• CRESST– Technique– Status– Next Future
• EDELWEISS– Technique– Status– Next Future
• EURECA– Idea– Plans– Status
Wolfgang Rau, TUM Future Direct Detection, Chicago 12/04 5
CRESST – TechniqueW-TES: (Tc = 6-10 mK)
Heater for stabilization (DC)and calibration (test pulses)
6 8 mm²
Al contact
W
Au heater
Target: CaWO4
• 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, TUM Future Direct Detection, Chicago 12/04 6
CRESST – Technique
W-band
-band
Recoil energy
Lig
ht e
nerg
y
Quenching
• Different light yield for different nuclei (O, Ca, W)?
Two experiments to measure Quenching (so far room temp.):• Neutron scattering• Ion beamBoth indicate: less light for heavy nuclei
Additional support from data
ReflectorC
aWO
4
• -band between - and n-band• recoiling nuclei from -decay
-band
n-band
• Nuclear recoil less light than electron recoil!
(O)
Wolfgang Rau, TUM Future Direct Detection, Chicago 12/04 7
CRESST – Technique
3600 m w.e.
Gran Sasso
Wolfgang Rau, TUM Future 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
yie
ld
Run 28, Daisy
Energy in Phonon Channel [keV]
Light
yie
ld
Energy in Phonon Channel [keV]
Run 28, Julia (bad light resolution)
Wolfgang Rau, TUM Future Direct Detection, Chicago 12/04 9
CRESST – StatusSince 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. -veto66 SQUIDs on
He-flange
Wolfgang Rau, TUM Future 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, TUM Future Direct Detection, Chicago 12/04 11
EDELWEISS - TechniqueTarget:cyl. Germanium crystal, 320 g 7.0 cm, height 20 mm (beveled)
Ionization: Inner disk / outerring (“guard”)with -Si / -Ge
Thermal:NTD(~ 20 mK)
Wolfgang Rau, TUM Future 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 keVPhon. trig.: 15 keV
Resolution Heat: 0.6 – 2 keV @ 10 keV
2 – 4 keV @ 122 keV Ion.: 2 – 3 keV @ 122 keV
Wolfgang Rau, TUM Future 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, TUM Future Direct Detection, Chicago 12/04 14
EDELWEISS - StatusNbSi 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, TUM Future 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 II @ Modane (4800 m w.e.)
Wolfgang Rau, TUM Future 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, TUM Future Direct Detection, Chicago 12/04 17
EURECA
uropeannderground
arevent search with
alorimeterrray
EURECA
Wolfgang Rau, TUM Future 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, TUM Future Direct Detection, Chicago 12/04 19
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
Wolfgang Rau, TUM Future 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
ILIAS