The EDELWEISS-III Dark Matter Search Bernhard Siebenborn, for the EDELWEISS collaboration KIT – University of the State of Baden-Wuerttemberg and National Research Center of the Helmholtz Association www.kit.edu The EDELWEISS Collaboration CEA Saclay (IRFU and IRAMIS) CSNSM Orsay (CNRS/IN2P3 + Paris Sud) IPNLyon (CNRS/IN2P3 + Univ. Lyon 1) Néel Grenoble + LPN Marcoussis (CNRS/INP) Karlsruhe Inst. of Technology (IKP, EKP, IPE) JINR Dubna Oxford University University of Sheffield FRANCE Altitudes Distances 1228 m 0 m ITALIE 1263 6210 m m 1298 m 12 868 m Laboratoire Souterrain de Modane (LSM) in Fréjus Tunnel 4800 mwe depth: ~5 muon/day/m2 10-6 neutrons/cm2/s (>1MeV) Deradonized air facility (~10 Bq/m³ ~30 mBq/m³) 2 26th Recontres de Blois | 21st May 2014 Bernhard Siebenborn EDELWEISS schematic setup e+,e-, g, Pb shield Cryostat n, Polyethylene shield m, Muon Veto 3 26th Recontres de Blois | 21st May 2014 Bernhard Siebenborn EDELWEISS setup 4 26th Recontres de Blois | 21st May 2014 Bernhard Siebenborn Cryogenic Germanium bolometers ΔT ~ Erecoil → total event Energy NTD e- Phonons Scatt. WIMP Challenges: Low event rate: <1 evt/kg/year Small energy deposit: ~ 10 keV Background events by: b, g, n m - induced background Q → particle identification WIMP h+ Ge detector at 18 mK Simultaneous measurement of heat and ionization Neutron Transmutation Doped (NTD) thermal sensor calorimetric measurement of total energy A. Benoit et al. NIMA 577 (2007) 558 Ionization yield: Q = EIon/ERec nuclear recoils have ~1/3 Q of e- recoils 5 26th Recontres de Blois | 21st May 2014 Bernhard Siebenborn Surface event rejection in EDELWEISS NTD C1: +4 V NTD Phonon/Heat sensor: calorimetric measurement of total energy (T=18 mK, ΔT 0.1 mK/keV ) V1: -1.5V Al electrodes: Ionization measurement (sub-keV resolution) C2: -4 V V2: +1.5V NTD Bulk/Fiducial event Charge collected on electrodes C1&C2 6 Surface event Charge collected on electrodes C&V 26th Recontres de Blois | 21st May 2014 Bernhard Siebenborn FID surface event rejection power 105 x 210Pb b + 105 x 210Bi b + 105 x 210Po a + 105 x 206Pb recoil Measurement with 210Pb b-source ~105 kg.d equivalent Surface rejection: < 4 x 10-5 misidentified events per kg.d (Erec>15 keV) Better than previous EDELWEISS detectors < 6 x 10-5 misidentified events / kg.d Erec>20 keV 99.99%CL g-band preliminary 7 26th Recontres de Blois | 21st May 2014 Bernhard Siebenborn g rejection power in EDELWEISS-II EDELWEISS-II ID 400g with 10x 160g fiducial mass ~160g ID (350000 g) g rejection power of ID detector: 3 ∙ 10−5 𝑁𝑅 𝛾 8 26th Recontres de Blois | 21st May 2014 Bernhard Siebenborn Results of EDELWEISS-II, 384 kgd Edw-II: CDM analysis for O(100 GeV/c2) WIMP mass 1 year/384 kgd of exposure 5 events observed 3 background events expected 9 26th Recontres de Blois | 21st May 2014 Bernhard Siebenborn EDELWEISS-II low mass WIMP analysis results Low energy analysis of high quality EDW-II data (4 ID detectors) EDELWEISS-II: Phys. Rev. D, 86, 051701, (2012) 4/10 ID detectors (~113 kg d) 95% C.L. gamma cut Background expect.: γ + ion. threshold + n: 2.9 evts / 1 observed sSI (pb) 1.4 – 1.9 keV Ionization threshold EDELWEISS-II Mc (GeV) 10 26th Recontres de Blois | 21st May 2014 Bernhard Siebenborn EDELWEISS-II low mass WIMP analysis results Low energy analysis of high quality EDW-II data (4 ID detectors) 90%SuperCDMS 68%-95%pre-unblinding SCDMS 90%CDMS II Si 90%CoGeNT 95%CRESST-II 90%DAMA/LIBRA 90%CDMS II Ge 90%CDMS II Ge low-thr. 90%CDMSlite 90%LUX 90%XENON10 S2-only 90%EDELWEISS low-thr. 4/10 ID detectors (~113 kg d) EDELWEISS 1.4 – 1.9 keV Ionization threshold 95% C.L. gamma cut Background expect.: γ + ion. threshold + n: 2.9 evts / 1 observed SuperCDMS arXiv:1402.7137 11 26th Recontres de Blois | 21st May 2014 Bernhard Siebenborn Axion results with EDELWEISS-II data 68 Ge 68 Ga 65 Rate (counts/kg×d×keV) Zn 49 V 54 EDELWEISS is sensitive to e- recoils down to 2.5 keV → ideal for axion searches Very low background due to fiducial selection Compton scattering 10 55 Mn Fe 1 10-6 10 6 8 10 12 14 16 ~ Electron recoil energy E (keV) 18 10-7 20 g Axion limits (Primakoff, axio-electric, solar or dark matter scenarios with axion like particles) Ae 10-8 ED EL W C uo r EI D er bi n e R SS D FS Z 4 K SV Z B or ex in o -1 & D 10-9 Derbin 10-10 10-11 XMASS Solar neutrinos EDELWEISS CoGeNT -12 10 EDELWEISS CDMS Red giant JCAP11(2013)067 10-13 -5 10 10-4 -3 10 10-2 10-1 1 10 Axion mass (keV) 12 26th Recontres de Blois | 21st May 2014 Bernhard Siebenborn 102 3 10 104 5 10 EDELWEISS-III improvements New Kapton cabling Improved radiopurity connectors Kapton cables Internal PE shielding at 1K stage Bolometer fiducial mass 160g -> 600g New DAQ electronics Bolo plate Upgraded cryogenic system Background (20–200 keV) EDW-II (evt / kg.d) Gamma rate ambient n´s µ-induced n´s 82 < 8.1∙10-3 < 2∙10-3 Astropart. phys. 47 (2013) 1 Astropart. phys. 44 (2013) 28 13 26th Recontres de Blois | 21st May 2014 Bernhard Siebenborn EDW-III (evt / kg.d) New PE (1K) 14 – 44 (0.8 – 1.9)∙10-4 < 2∙10-4 Roman Pb Increased g rejection power in EDELWEISS-III EDELWEISS-II ID 400g with 10x 160g fiducial mass ~160g ID (350000 g) 3 ∙ 10−5 𝑁𝑅 𝛾 FID (411000 g) < 6 ∙ 10−6 𝑁𝑅 𝛾 EDELWEISS-III FID 800g with ~600g fiducial mass Fiducial Volume > 600 g 14 26th Recontres de Blois | 21st May 2014 Bernhard Siebenborn EDELWEISS-III DAQ system 1x Integration of external detectors such as muon veto → trigger on muons All components run with the same clock → synchronized data 3x 72x 36x detector at 18mK 36x analog amplification at 100K with FET BBv2: analog/digital conversion Detector bias inner shielding 15 Cryostat 26th Recontres de Blois | 21st May 2014 Bernhard Siebenborn data acquisition, triggering, clock Similar to Auger and KATRIN crate data acquisition, triggering and storage (DAQ) continuous control Principle of the digital DAQ fiber in/out 3 Bolometers FPGA Trigger Backplane FPGA commands clock PCIe interface PCIe input cards (20x) 1…6x FIFO Master Card Linux Computer: Memory ring buffer event buffer 16 26th Recontres de Blois | 21st May 2014 Bernhard Siebenborn Server for the DAQ PCs 400 Mbit/s data rate to DAQ PCs (gigabit Ethernet) Additional information from time resolved ionization signals NTD C1 +4 V NTD V2 +1.5 V V1 -1.5 V Monte Carlo simulation C2 -4 V Additional spatial information on z-axis of bolometer Improved understanding of charge migration Identifying double scatter events Surface event rejection Event based readout needed for 40 MHz channel → Trigger on ionization channel Amplitude normalized 1 C1 26th Recontres de Blois | 21st May 2014 Bernhard Siebenborn C2 -1 Broniatowski, A. et al. PLB 681 (2009) 17 V2 0 0 1 Time in µs Trigger algorithm for time resolved channel “slow” 100 kHz “fast” 40 MHz input card Analog / digital converter box analog data 100 kHz 16 bit ADCs 40 MHz 16 bit ADCs 18 FPGA continuous 100 kHz stream FPGA Trigger FPGA memory 26th Recontres de Blois | 21st May 2014 Bernhard Siebenborn 40 MHz event readout Memory ring buffer event buffer Current EDELWEISS status Upgraded cryogenics Upgraded readout electronics New Kapton cables Inner PE shield + new Cu screens 36 FID 800 detectors installed 3 ZnMoO4 detectors installed (0νββ) 19 26th Recontres de Blois | 21st May 2014 Bernhard Siebenborn Future experiment: EURECA 200 kg scale WIMP search → “Low mass WIMPs” Upgrade to a 1000 kg scale → MSSM WIMPs Combined use of CaWO4 and Ge detectors (CRESST-, EDELWEISS-Type) Cooperation with SuperCDMS Design of a common cryogenic facility at SNOLAB Joint EDELWEISS CDMS paper Phys. Rev. D 84, 011102(R) 20 26th Recontres de Blois | 21st May 2014 Bernhard Siebenborn Conclusion and outlook EDW-II: 10 ID Ge bolometers mdet = 400g; mfid = 160g → 1.6kgfid EDW-III: 40 FID Ge bolometers mdet = 800g; mfid = 600g → 24kgfid reduction of bgd (gammas: 2-6; neutrons >10) EDW-III 3000 kgfid exposure in 6 months EDW-III 12000 kgfid ultimate exposure EDW-III detector technology ready for 1-ton cryogenic array 21 26th Recontres de Blois | 21st May 2014 Bernhard Siebenborn
© Copyright 2024 ExpyDoc
