Cryogenic charge and phonon detectors: EDELWEISS-SubGeV J. Billard Institut de Physique Nucléaire de Lyon / CNRS / Université Lyon 1 Light Dark Matter Workshop Chicago, June 3-7, 2019 1
EDELWEISS-SubGeV: Scientific context eV keV MeV GeV TeV Absorption DM-electron scattering DM-Nucleus scattering Electronic recoil Electronic recoil Nuclear recoil Standard WIMP Hidden sector Dark Matter and others 8 B neutrinos (~ 6 GeV) Reactor neutrinos (~ 2.7 GeV) EDELWEISS-SubGeV program Not competitive with High Voltage Low Voltage High Voltage Low Voltage noble gases experiments single e/h Part. ID + Fid single e/h Part. ID + Fid 2 J. Billard (IPNL)
EDELWEISS-SubGeV: Detector technology EDELWEISS-SubGeV: aiming for a kg-scale payload of 30 to 200g Ge detectors running in two modes: • Low Voltage: Particle ID - ER/NR/‘unknown backgrounds’ - and fiducialization (synergy with Ricochet) • High Voltage: single-e/h sensitivity by operating in a Neganov-Luke mode Detector wish list: 1) Scalability to significant payload: 1 kg (30 to 200 g crystals) 2) Heat energy resolution (RMS): 10 eV 3) EM background rejection (LV mode): >10 3 4) Operation at high voltages (HV mode): 100V Goals 1-to-3 are part of a common effort with the Ricochet collaboration, dedicated to studying CENNS at reactors, in the construction of the C RYO C UBE detector supported by the ERC- CENNS Starting Grant (2019-2024) C RYO C UBE 3x3x3 - 30g crystals 3 J. Billard (IPNL)
Goal #1: Scalability and holding system • High impedance sensors (NTD, NbSi TES and electrodes) are highly sensitive to microphonics • Highly efficient cryogenic suspension system designed to host kg-scale payloads: • sub micro-g/sqrt{hz} level over the detector bandwidth ( limited by accelerometer sensitivity ) • Detectors are now running in optimal conditions, only limited by thermodynamic and electronic noises R. Maisonobe et al. , JINST 2018 J. Billard (IPNL) 4
Goal #2: Heat energy resolution 10 eV (rms) E. Armengaud et al., Phys. Rev. D 99, 082003 (2019) Major accomplishment: 18 eV energy resolution (RMS) 55 eV energy threshold with a 33.4 g detector (Ge) near perfect stability (~%) PSD from 137 hours displayed • Optimisation of thermal design based on a fully data driven electro-thermal modeling (D. Misiak et al., in preparation) • Large improvement on heat energy resolution: • 20 eV (RMS) on four 33.4 g Ge crystals • 50 eV (RMS) on a 200 g Ge crystals • Achieved in above-ground operation (IPNL) • Thanks to enhanced thermal response sensitivity and improved noise conditions (suspension) J. Billard (IPNL) 5
Goal #2: Heat energy resolution 10 eV (rms) E. Armengaud et al., Phys. Rev. D 99, 082003 (2019) Major accomplishment: 18 eV energy resolution (RMS) 55 eV energy threshold with a 33.4 g detector (Ge) near perfect stability (~%) PSD from 137 hours displayed • Optimisation of thermal design based on a fully data driven electro-thermal modeling (D. Misiak et al., in preparation) FET • Large improvement on heat energy resolution: • 20 eV (RMS) on four 33.4 g Ge crystals • 50 eV (RMS) on a 200 g Ge crystals • Achieved in above-ground operation (IPNL) HEMT • Thanks to enhanced thermal response sensitivity and (anticipated) improved noise conditions (suspension) Limited by FET current noise, switch to HEMT in order to reach 10 eV (RMS) on 33.4 g crystals J. Billard (IPNL) 5
Goal #2: Heat energy resolution 10 eV (rms) - 24 10 - 25 10 E. Armengaud et al., Phys. Rev. D 99, 082003 (2019) - 26 10 - 27 10 ] 2 - 28 WIMP-nucleon cross section [cm 10 - 29 10 - 30 10 - 31 10 - 32 10 - EDELWEISS-Surf (Standard) 33 10 EDELWEISS-Surf (Migdal) - 34 10 EDELWEISS-III LT - 35 CRESST Surface 10 - CRESST-II + CRESST-III 36 10 SuperCDMS LT - 37 10 CDMSLite - 38 LUX (Standard) 10 - LUX (Migdal) 39 10 XENON1T (Standard) - 40 10 XENON100 LT - 41 NEWS-G 10 DarkSide (Standard) - 42 10 XQC - 43 10 CMB - 44 Neutrino discovery limit 10 - 45 10 - - - - ´ ´ 2 2 1 1 10 2 10 10 2 10 2 3 4 5 6 7 1 10 2 WIMP Mass [GeV/c ] • DM - Nucleus interaction: first Ge-based limit below 1.2 GeV and best above ground limit down to 600 MeV • Migdal effect : first DM limit down to 45 MeV limited by Earth-Shielding effect (B. Kavanagh, 2017) , which becomes significant > 10 -31 cm 2 (plans to measure this effect with the EDELWEISS experimental setup) J. Billard (IPNL) 6
Goal #2: Heat energy resolution 10 eV (rms) - 24 10 - 25 10 E. Armengaud et al., Phys. Rev. D 99, 082003 (2019) - 26 10 - 27 10 ] 2 - 28 WIMP-nucleon cross section [cm 10 - 29 10 - 30 10 - 31 10 - 32 10 - EDELWEISS-Surf (Standard) 33 10 EDELWEISS-Surf (Migdal) - 34 10 EDELWEISS-III LT - 35 CRESST Surface 10 - CRESST-II + CRESST-III 36 10 SuperCDMS LT - 37 10 CDMSLite - 38 LUX (Standard) 10 - LUX (Migdal) 39 10 XENON1T (Standard) - 40 10 XENON100 LT Reactor neutrinos - 41 NEWS-G 10 10 12 /cm 2 /s DarkSide (Standard) - 42 10 XQC - 43 10 CMB - 44 Neutrino discovery limit 10 - 45 10 - - - - ´ ´ 2 2 1 1 10 2 10 10 2 10 2 3 4 5 6 7 1 10 2 WIMP Mass [GeV/c ] • DM - Nucleus interaction: first Ge-based limit below 1.2 GeV and best above ground limit down to 600 MeV • Migdal effect : first DM limit down to 45 MeV limited by Earth-Shielding effect (B. Kavanagh, 2017) , which becomes significant > 10 -31 cm 2 (plans to measure this effect with the EDELWEISS experimental setup) J. Billard (IPNL) 6
Goal #3: EM background rejection of O(10 3 ) 20 eV ionization resolution: HEMT preamplifiers + new electrode design HEMT 1 HEMT 2 HEMT 3 10 2 Resolution [eV] FET to HEMT FET 100 pF 35 pF Goal 5 pF 10 1 10 0 10 1 10 2 Cdetector[pF] • As initiated by the CDMS-Berkeley group (arXiv:1611.09712) we are transitioning to HEMT based preamplifiers. • HEMT have lower intrinsic noise than JFET • Work @ 4/1 K allowing to reduce the stray capacitance • Based on our data driven HEMT model , O (10) eV rms reachable with ~20 pF total input impedance • HEMT characterizations are ongoing • First HEMT-based preamp to be tested in winter 2019 ! • Synergie with the Ricochet-CryoCube collaboration J. Billard (IPNL) 7
Goal #3: EM background rejection of O(10 3 ) 20 eV ionization resolution: HEMT preamplifiers + new electrode design Simulation Ge FID h10d30 Potential V E Field Norm • Design of new electrode scheme with following specs.: in V log10(|E|) (left) (right) • Low input capacitance (10 to 20 pF) • High surface event rejection efficiency (FID mode) • Large fiducial volume (75%) • Aim at O(10 3 ) EM background rejection down to 50 eVnr • Synergie with the Ricochet-CryoCube collaboration RED30: 28 eV heat, 205 eV ionization (24h) Nuclear-recoil equivalent energy [keVnr] 73 Ge L-shell 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 s l 0.15 1.3 keV i Ionization energy [keVee] o c Vetoed e r c i Gammas n o r t c Betas e l E 0.1 Lead Neutrons FET to HEMT CENNS 0.05 73 Ge M-shell 160 eV Nuclear recoils 0 Reactor neutrinos / ~2.7 GeV WIMP No ionization 0.05 − 0 0.1 0.2 0.3 0.4 J. Billard (IPNL) Julien Billard 8 Heat energy [keV]
Goal #4: Operation at high voltage (~100 V) High Voltage: Exploring DM-electron/nucleus interactions with near single-electron sensitivity achieved in massive bolometers operated underground (low-background environment ~ 1 - 0.1 DRU). NbSi209 Preliminary 10.4 keV 10.4 keV RED30 Preliminary 66 Volt 70 Volt 1.3 keV s = 5 eV ee 1.3 keV s = 1.8 eV ee 160 eV DM DM 160 eV search search zone zone First EDELWEISS DM-electron scattering and absorption results expected by fall 2019. J. Billard (IPNL) 9
Conclusions Take away points: • From the last few years, there has been an increasing interest in the low-mass dark matter region motivated by lack of evidence of new physics (e.g. LHC, DM searches, …): • Beyond the standard WIMP Dark Matter scenario • The EDELWEISS-SubGeV program aims at probing this new region of interest with detectors able to provide: • Particle identification and surface event rejection down to 50 eVnr (Low Voltage) • Single-e/h sensitivity on massive bolometers (High Voltage) • The low-voltage R&D program is now focusing on the front-end HEMT preamplifier and electrode design • first detector prototypes achieving 10 eV heat and 20 eV ionization resolutions by 2020 (Ricochet-CryoCube) • Goal is to reach to reach O (10 -43 ) cm 2 from 1 GeV to 10 GeV with 1 kg payload in one year at Modane • The high-voltage R&D program is near single-e/h sensitivity on 33.4 g and 200 g Ge crystals operated at Modane. • First science results expected in fall 2019 ! 10 J. Billard (IPNL)
Back-up 11
Goal #2: Heat energy resolution 10 eV (rms) 24h above-ground with moderate lead shield 5.90 keV 6.49 keV Not e ffi ciency corrected 34 eV (RMS) 34 eV (RMS) Event rate [evts/kg/keV/day)] E. Armengaud et al., Phys. Rev. D 99, 082003 (2019) 7 10 Data Noise induced triggers 6 6 10 10 Residual 5 10 4 5 10 10 0.05 0.1 0.15 0.2 4 10 0 1 2 3 4 5 6 7 8 Energy [keV] 12 Trigger threshold: 55 eV J. Billard (IPNL)
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