dark matter search with edelweiss and beyond
DESCRIPTION
Dark Matter search with EDELWEISS and beyond. Gilles Gerbier CEA Saclay – IRFU Rencontres de M oriond - VHEPU march 15 th 2013. European Underground Rare Event Calorimeter Array. Expérience pour DEtecter Les Wimps E n SIte Souterrain. The EDELWEISS collaboration. 4800 mwe. - PowerPoint PPT PresentationTRANSCRIPT
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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