EURECA, CRESST and EDELWEISS
Johannes Blümer, Karlsruhe Institute of Technology
(1) The cooperation of Forschungszentrum Karlsruhe GmbH | JohannesProjektbüro Blümer KIT | 22 July 2007 and Universität Karlsruhe (TH) EURECA, CRESST and EDELWEISS
Johannes Blümer, Karlsruhe Institute of Technology
(1) The cooperation of Forschungszentrum Karlsruhe GmbH | JohannesProjektbüro Blümer KIT | 22 July 2007 and Universität Karlsruhe (TH) European Underground Rare Event Calorimeter Array
• Started March 2005; based initially on EDELWEISS and CRESST, with additional groups joining.
• Target materials: Ge, CaWO4, etc (A dependence) • Mass: above 100 kg towards 1 ton • CRESST-II and EDELWEISS-II are EURECA R&D • Aligned with Roadmap Recommendations: Multiple targets and multiple techniques The Collaboration
CRESST, EDELWEISS, ROSEBUD + CERN, others
United Kingdom France Oxford (H Kraus, coordinator) CEA/IRFU Saclay Germany CEA/IRAMIS Saclay MPI für Physik, Munich CNRS/Neel Grenoble Technische Universität München CNRS/CSNSM Orsay Universität Tübingen CNRS/IPNL Lyon Universität Karlsruhe CNRS/IAS Orsay Forschungszentrum Karlsruhe Spain International Zaragoza JINR Dubna Ukraine CERN Kiev Physics Aims / Requirements
Probe currently most favoured cross section in the region 10−8 pb to 10−10 pb. Requires a target mass of ~ 1000 kg for few events / year. Use cryogenic detectors (scalable, mature technology). Cryogenic detectors offer excellent discrimination nuclear / electron recoil, energy resolution and large potential for further background rejection. Use range of targets for positive identification of signal. Use complementary cryogenic detectors in common volume to reduce systematic uncertainty. Detection Techniques
Ar, Xe ArDM, WARP, XENON, ZEPLIN, LUX
NaI Ge DAMA HDMS LIBRA Genius-TF ANAIS IGEX NAIAD DRIFT
CaWO Si, Ge 4 Al O 2 3 CDMS CRESST II CRESST I ROSEBUD EDELWEISS Detection Techniques
Ar, Xe ArDM, WARP, XENON, ZEPLIN, LUX
NaI Ge DAMA HDMS LIBRA Genius-TF ANAIS IGEX NAIAD DRIFT
CaWO Si, Ge 4 Al O 2 3 CDMS CRESST II CRESST I ROSEBUD EDELWEISS EURECA CRESST in LNGS CRESST – Detectors
heat bath normal- ] thermal link Ω conducting
thermometer δR (W-film)
Resistance [m super- δT conducting absorber crystal Width of transition: ~1mK Signals: few µ K Stability: ~ µ K Particle interaction in absorber creates a temperature rise in thermometer which is proportional to energy deposition in absorber
Temperature pulse (~6keV) Phonon – Scintillation
Discrimination of nuclear recoils from radioactive backgrounds (electron recoils) by simultaneous measurement of phonons and scintillation light
reflecting cavity
] 140 ee
Silicon W-SPT 120 absorber
100 CaWO4 absorber 300g 80 γ and β 60 n
40 Pulse Height in Light Detector [keV 20 W-SPT 0 20 40 60 80 100 120 140 0 Pulse Height in Phonon Detector [keV] Phonon – Scintillation
Discrimination of nuclear recoils from radioactive backgrounds (electron recoils) by simultaneous measurement of phonons and scintillation light
reflecting cavity
] 140 ee QF γ, β =1 Silicon W-SPT 120 absorber
100 CaWO4 absorber 300g 80 γ and β 60 n
40 Pulse Height in Light Detector [keV 20 W-SPT 0 20 40 60 80 100 120 140 0 Pulse Height in Phonon Detector [keV] Phonon – Scintillation
Discrimination of nuclear recoils from radioactive backgrounds (electron recoils) by simultaneous measurement of phonons and scintillation light
reflecting cavity
] 140 ee QF γ, β =1 Silicon W-SPT 120 QF =5 absorber α
100 CaWO4 absorber 300g 80 γ and β 60 n
40 Pulse Height in Light Detector [keV 20 W-SPT 0 20 40 60 80 100 120 140 0 Pulse Height in Phonon Detector [keV] Phonon – Scintillation
Discrimination of nuclear recoils from radioactive backgrounds (electron recoils) by simultaneous measurement of phonons and scintillation light
reflecting cavity
] 140 ee QF γ, β =1 Silicon W-SPT 120 QF =5 absorber α QF O-recoils=9 100 CaWO4 absorber 300g 80 γ and β 60 n
40 Pulse Height in Light Detector [keV 20 W-SPT 0 20 40 60 80 100 120 140 0 Pulse Height in Phonon Detector [keV] Phonon – Scintillation
Discrimination of nuclear recoils from radioactive backgrounds (electron recoils) by simultaneous measurement of phonons and scintillation light
reflecting cavity
] 140 ee QF γ, β =1 Silicon W-SPT 120 QF =5 absorber α QF O-recoils=9 100 CaWO 4 QF =40 absorber W-recoils 300g 80 γ and β 60 n
40 Pulse Height in Light Detector [keV 20 W-SPT 0 20 40 60 80 100 120 140 0 Pulse Height in Phonon Detector [keV] Phonon – Scintillation
Discrimination of nuclear recoils from radioactive backgrounds (electron recoils) by simultaneous measurement of phonons and scintillation light
reflecting cavity
] 140 ee QF γ, β =1 Silicon W-SPT 120 QF =5 absorber α QF O-recoils=9 100 CaWO 4 QF =40 absorber W-recoils 300g 80 γ and β 60 n
40 Pulse Height in Light Detector [keV 20 W-SPT 0 20 40 60 80 100 120 140 0 Pulse Height in Phonon Detector [keV] CRESST – Detector Module
CaWO4: h = 40mm, ∅ = 40mm m = 300g CRESST – Detector Module
CaWO4: h = 40mm, ∅ = 40mm m = 300g CRESST Upgrade CRESST Upgrade CRESST Energy Resolution
Energy Spectrum of one (1) CRESST detector (“Verena”) – external 57Co calibration
350 122keV
300 Counts
250
200
∂E ≈ 1 keV @ 46.5 keV to identify 150 210-Pb contaminations
100 Kβ Kα1 Kα2 136keV 50 Kα 0 0 20 40 60 80 100 120 140 Recoil Energy [keV] CRESST – Run 30 Result Exclusion Plot Edelweiss / EURECA in LSM Edelweiss in LSM
Large cryostat: 100 detectors (320g each). Currently: 27, of which 7 7 have active surface 40 t Pb shield against gamma, 40 t polyethylene shield against bg rejection (next) neutron. Muon veto, Clean room, selection of material, deradonized air. EDELWEISS Detectors 2008
New surface event rejection detector 12 * 400g detectors in fabrication and operated by end 2008
NTD 300g detectors EDW1 22.7 kg.d Interdigit Electrodes 200g 4 kg.d Edelweiss in LSM
1 t liquid scintillator installed last week to measure CR-induced neutron background EURECA in LSM
Deepest site in Europe (4800 mwe) Clean Infrastructure 24 years experience Central location within Europe EURECA in LSM
second tunnel ⇉ extension opportunity A Possible Facility Layout
A Benoit Neel Institute Grenoble
12m prep water physics run cryo
12m 30m Readout Systems and DAQ
Optical Cold electronics Boîtier fibres Fibre Optics Boîtier CPU numériseurBoîtier Receivers numériseurBoîtier acquisition numériseurBoîtier numériseur Level 1 numériseurBB box Trigger
Calorimeters Front End Electronics Phonon / Ionisation Low-impedance CPU Phonon / Scintillation High-impedance acquisition
Cryostat EDELWEISS Approach CPU Control Cryostat / Slow Control event builder Monitoring of Environment
Archive Timeline
2008 Grant applications / first financial support arrives. Low-cost studies ongoing. 2009/10 Design Study Phase 2011 Begin construction in home institutes and test in temporary underground space 2014 Bring experiment into LSM
Current (summer 2008) effort: how to fit EURECA into LSM extension – shielding / cryostat design. Science Results and Aims
~1 evt/kg/day
~3 evt/kg/year
~30 evt/ton/year