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Dark Matter search with EDELWEISS and beyond

Gilles GerbierCEA Saclay – IRFU

Rencontres de Moriond- VHEPU march 15th 2013

Expérience pour DEtecter Les Wimps En SIte Souterrain

European Underground Rare Event Calorimeter Array

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• CEA Saclay (IRFU and IRAMIS)• CSNSM Orsay (CNRS/IN2P3 + Univ.

Paris Sud)• IPN Lyon (CNRS/IN2P3 + Univ. Lyon

1)• Institut Néel Grenoble (CNRS/INP)• LPN Marcoussis (CNRS)• Karlsruhe Institute of Technology• JINR Dubna• Oxford University• Sheffield University

Karlsruhe

The EDELWEISS collaboration

4800 mwe

Laboratoire Souterrain de Modane - LSM

(Fréjus tunnel)

LSM

J Gascon/IPNL : spokesman

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The EDELWEISS-II infrastructure

cryostat

Polyethylene shield

Pb shield

Muon Veto

Neutron counter

3He detector

Innovative dilution cryogenic set-up (18 mK) : Can host up to 40kg of detectors

Shieldings : Clean room + deradonized air 10 mBq/m3 Active muon veto (>98% coverage) 50-cm PE shield + 20-cm lead shield

Other side monitoring detectors: Radon detector down to few mBq/m3

He3 neutron detector (thermal neutron monitoring inside shields) sensitivity ~10-9 n/cm2/s

Liquid scintillator neutron counter (study of muon induced neutrons)

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The EDELWEISS-II infrastructure

cryostat

Polyethylene shield

Pb shield

Muon Veto

Neutron counter

3He detector

Cryogenic installation (18 mK) : Can host up to 40kg of detectors

Shieldings : Clean room + deradonized air 10 mBq/m3 Active muon veto (>98% coverage) 50-cm PE shield + 20-cm lead shield

Other side monitoring detecetors: Radon detector down to few mBq/m3

He3 neutron detector (thermal neutron monitoring inside shields) sensitivity ~10-9 n/cm2/s

Liquid scintillator neutron counter (study of muon induced neutrons)

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Detector principles : 3 parameters to isolate signal Germanium bolometers @ 17 mK

Ionization measurement @ few V/cm Heat measurement (NTD sensor) Discriminating variable between ER and NR

« Q » = ionization/recoil energy

Neutron calibration(S. Scorza PhD thesis)

nuclear recoils (NR)

electron recoils (ER)

Fiducialvolume

A: +4 V

B: -1.5V

C: -4 V

D: +1.5V

= Ionization « VETO » = > « Surface/beta » identification : if non zero, reject event

NB : idea first presented by CDMS group at LTD

Recent: ID400

Old : GeNTD

Fiducial annular electrodes

Guard planarelectrode

Allplanarelectrode

VETO B

VETO D

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Detector principles : 3 parameters to isolate signal Germanium bolometers @ 17 mK

Ionization measurement @ few V/cm Heat measurement (NTD sensor) Discriminating variable=

« Q » = ionization/recoil energy

Neutron calibration(S. Scorza PhD thesis)

nuclear recoils (NR)

electron recoils (ER)

Fiducialvolume

A: +4 V

B: -1.5V

C: -4 V

D: +1.5V

Surface identification = Ionization VETOIf non zero, reject event

New : ID400

Old : GeNT

Fiducial annular electrodes

Guard planarelectrode

Allplanarelectrode

1 evt

6x104

210Pb

6x104

210Bi

6x104

210Po

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EDELWEISS II limits (2011) and EDELWEISS -CDMS combined analysis

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. EDW II: 384 kg.d, [20-

200keV], 5 evts CDMS: ~379 kg.d,

[~10-100keV], 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

Recent EDELWEISS low mass analysis

Realization that, despite being tuned for MWIMP~100 GeV, EDELWEISS-II had significant efficiency down to 5 keV recoil

Significant background rejection with ID electrodes down to low energy wth subset of data => significant improvement down to 7 GeV WIMP mass

Resolutions are improving with new electronics (FWHM 900 eV -> 650 eV for ionization, 1.25 -> <1 keV for heat)

500 eV achieved in tests (HEMT R&D to go down to 300 eV?)

25 octobre 2012 EDELWEISS-III report to CSIN2P3

EDW II LE

PRD 86 (2012) 051701R

10 GeV WIMP – ID3

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Expected pattern f(E,t) for given orientationangle of crystal vs sun directionNB : electron recoils

Searching for axions Detection/production by Primakov effect gag

Solar axions g->g+a ------------------>a+g->g f(E, t, a) Bragg diff

PreliminarySingle detectorEdelweiss II

PhD Work of T de BoissiereOther constraints on gae ma currently studied

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EDELWEISS-III : few 10-9 pb sensitivity @ 60 Gev Detectors

40 FID800 detectors 24 kg fiducial, installed 2013 (factor 15 wrt before)

2 NTD sensors/detector

Current EDW-II setup : major upgrade new cabling, cold electronics new cryogenics (lower mphonic noise) new internal PE shielding replacement of thermal shields with lower

activity Cu

=> Expect lower thresholds, lower background (g and n), and redondancy

Program (1.6 M€) funded : upgrade finished at 95 %, cool down on going (march 2013) with 15 detectors

Results by 2014

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EDELWEISS III : new detectors FID800

• Fid mass *4 wrt to ID400• No NR event in g

calibration• Expected to be and indeed

better than IDs !

FID800(410 000 g) ID400 (350 000 g)

Fiducialmass

~640gAll annular electrodes

Coverage of low-mass region with 4 FID detectors with 300 eV FWHM resolutions (1200 kgd), 3 keV Er threshold thanks to new HEMT replacing JFET

1 evt,10 keV thresh12 000 kg.j

EDELWEISS-III : improved 5-15 GeV sensitivity

HEMT R&D ongoing

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EURECA Status 2013 EDELWEISS+CRESST +others (19) CDR written Baseline : 2 phases: 150 kg then1 t Choice of balance Ge / CaWO4 to be

optmised vs physics reach at time t Basic features

Favored site : LSM : deepest in Europe

Large water active shield 7 mK base temp , « scalable

cryogenics » see P Camus Flexible design for different detectors Tower design : fully integrated, 7mk-

300k see H Kraus No common official proposal

submitted yet Strong will to make common

project with S-CDMS

New

Actual

50 m

Last status jan 2013 Excavation of the extension 2014 or 2015. In operation in 2016/2017. Detailed studies funded by Savoie

departement and Rhone-Alpes Region Agreement from Ministery and CNRS for

the project Funding in progress (85% already obtained

CNRS, Region Rhone-Alpes, FEDER funds) Technical discussion in progress

France Italy

LSM underground lab extension

New

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Summary , prospects