present and future cryogenic dark matter search in europe wolfgang rau, technische universität...

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) + ...


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


Overview

• CRESST– Technique– Status– Next Future

• EDELWEISS– Technique– Status– Next Future

• EURECA– Idea– Plans– Status


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


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)


CRESST – Technique

3600 m w.e.

Gran Sasso


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)


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


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)


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)


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


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)


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


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.)


EDELWEISS – Next Future

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

• Improved shielding – 20 cm lead– 50 cm PE– Muon veto


EURECA

uropeannderground

arevent search with

alorimeterrray

EURECA


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


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


EURECA – Plans

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

ILIAS

ILIAS


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 ???

present and future cryogenic dark matter search in europe wolfgang rau, technische universität...

Documents

tumfuture direct detection

europe wolfgang rau

europe slide

cresst technique wband

flange slide

si slide

different light yield

kev light detector