Darkside and the future Liquid Argon Dark Matter program

Transcription

1 Darkside and the future Liquid Argon Dark Matter program Giuliana Fiorillo Università di Napoli Federico II & INFN Napoli PM th Pisa Meeting on Advanced Detectors

2 DM direct detection WIMP χ Low mass a number of close contours and Low WIMP mass exclusion limits High mass no observations so far NATURE PHYSICS DOI:.38/NPHYS4039 High WIMP mass 2

3 DM direct detection WIMP χ Low mass a number of close contours and Lower energy threshold exclusion limits High mass no observations so far NATURE PHYSICS DOI:.38/NPHYS4039 Larger detector mass and lower background 3

4 DarkSide program Achieved the world best limit for dark matter searches with mass <8 GeV/c 2 Demonstrated ability to perform background free searches for dark matter with mass >30 GeVc 2 In a unique position to perform a zerobackground discovery program for dark matter through the neutrino floor boundary

5 The Global Argon Dark Matter Collaboration ArDM Single Global Program for Direct Dark Matter Searches DarkSide Currently taking data: ArDM, DarkSide-50, DEAP-3600 DEAP Next step: DarkSide-20k at LNGS (2021-) MiniCLEAN}A Last Step: 300 tonnes detector, location t.b.d (2027-) ] 2 [cm WIMP-nucleon σ SI Neutrino floor 1 DarkSide-50 (2018) DEAP-3600 (proj.) LZ (proj.) WARP (2007) DarkSide-50 (2015) DEAP-3600 (2017) LUX (2017) XENON1T (proj.) PANDAX-II (2017) XENON1T (2017) XENONnT (proj.) DarkSide-20k (0 t yr proj.) DarkSide-20k (200 t yr proj.) Future 300-tonne GADMC Detector (1kt yr proj.) Future 300-tonne GADMC detector (3kt yr proj.) 1 2 WIMP mass [TeV/c ] DarkSide-20k approved by INFN and NSF in 2017 Officially supported by LNGS, LSC, and SNOLab 30 tonnes (20 tonnes fiducial) of low-radioactivity underground argon 14 m 2 of SiPM coverage

6 The Global Argon Dark Matter Collaboration October 24, 2017 > 350 researchers from 80 Institutes

7 Liquid Argon as DM detection medium Pro Contra Target nucleus favored by form factor for high recoil energy golden events Dense and easy to purify High scintillation yield ~ 40 γ/kev High ionisation yield (W ~ 20 ev) Intrinsic 39 Ar radioactivity (1 Bq/kg) in atmospheric Ar (AAr) is the primary background for argon-based detectors Very powerful rejection capability for electron recoil background 7

8 DarkSide-50 design: how to defeat background Identification: ER/NR discrimination using PSD ER/NR discrimination via S2/S1 3D reconstruction of interactions (rejects γ and surface bkgs) Passive suppression: Isotopically depleted Argon Low radioactive materials Low radioactive light-detectors Active shielding: Neutron Veto (Liquid Scintillator) Muon Veto (Water Cherenkov Detector) 8

9 DarkSide-50 ER/NR Discrimination PSD vs S1 for 1422 kg d atmospheric argon (AAr) exposure 1.5x 7 ER events from 39 Ar activity in AAr and Zero NR events Suppression: AAr Vs UAr PLB 743, 456 (2015) f Energy [kev nr ] % 65% 80% 90% 95% 99% S1 [PE] Ar production supported by cosmogenic activation via 40Ar(n,2n) 39 Ar Underground argon (UAr): 150 kg successfully extracted from a CO2 well in Colorado PRD, 93 (2016): 0811(R) 39Ar in UAr < 1 mbq/kg 39 Ar depletion factor >1400 9

10 Reducing the energy threshold S1 scintillation signal threshold at 2 kevee kevnr S2 ionization signal threshold at <0.1 kevee 0.6 kevnr kg day] - Events / [0.5 N e First 0 days Last 500 days Single S2(500 d) S1 + S2(500 d) kg day] Events /[N e L/K BR 37Ar 0.27 kev Ratio = 0.11 ± 37Ar 2.8 kev N e N e - 37Ar from cosmic ray activation during UAr transport: 35 d τ1/2 to 37 Cl via electron capture

11 DarkSide-50 WIMP Currently Published searches Limits f Energy [kev nr ] % 50% 99% [cm 2 ] Dark Matter-Nucleon σ SI WARP (2007) DarkSide-50 (2018) PANDAX-II (2017) DarkSide-50 (2015) DEAP-3600 (2017) LUX (2017) XENON1T (2017) arxiv: S1 [PE] [TeV/c ] M χ kg day] - Events / [N e E [kevnr ] -40 DM spectra σ χ = 2 M χ =2.5 GeV/c 2 M χ =5.0 GeV/c 2 M χ =.0 GeV/c cm E [kevee] 3 Data G4DS MC All Cryostat γ-rays PMTs γ-rays 39 Ar + 85 Kr N e day] kg Events / [kevee 1 X. Xiang [cm 2 ] Dark Matter-Nucleon σ SI arxiv: DarkSide-50 Binomial DarkSide-50 No Quenching Fluctuation NEWS-G 2018 LUX 2017 XENON1T 2017 PICO PICASSO 2017 CDMSLite 2017 CRESST-III 2017 PandaX-II 2016 XENON DAMIC 2016 CDEX 2016 CRESST-II 2015 SuperCDMS 2014 CDMSlite 2014 COGENT 2013 CDMS 2013 CRESST 2012 DAMA/LIBRA 2008 Neutrino Floor [GeV/c ] M χ

12 Next steps in the DarkSide program DarkSide-Proto 1 tonne 1 m 2 of SiPM coverage ( ) DarkSide-20k 20 tonne, 14 m 2 of SiPM coverage ( ) 12

13 Two key technologies enabling DarkSide-20k and future LAr program Cryogenic SiPMs Abruzzo large area, cryogenic silicon photomultiplier optical modules assembly and test facility (Nuova Officina Assergi - NOA) Liquid argon target depleted in the radioactive 39Ar URANIA extraction of large quantities of underground argon ARIA Isotopic separation via cryogenic distillation 13

14 URANIA Procurement of 50 tonnes of UAr from same Colorado source as for DS-50 Extraction of 250 kg/day, with 99.9% purity UAr transported to Sardinia for final chemical purification at Aria ARIA Big cryogenic distillation column in Seruci, Sardinia Final chemical purification of the UAr Can process O(1 tonne/day) with 3 reduction of all chemical impurities Ultimate goal is to isotopically separate 39 Ar from 40 Ar ( kg/day in Seruci-I) 14

15 Nuraxi Figus PIM Cluj-Napoca m

16 SiPM to enhance LAr technology Advantages w/r to cryogenic PMTs Very compact, much lower radioactivity Light yield increase by 50% Greater stability Ten-fold reduction of costs per unit area SiPMs love to run at LAr temperature! A full chain (development-production-packaging-testing) strategy largely funded by Regione Abruzzo Custom SiPM development for cryogenic temperature (FBK) Industrial cooperation for large-scale production Radiopure packaging of the tiles and of the cryogenic FE readout board Massive test and selection of detector modules before installation in DS-20k First PDM, March

17 24 cm 2 single-channel detector 24 FBK NUV-HD-LF SiPMs with optimized form factor and performance improvement High density SPAD with high PDE Peak sensitivity at ~ 420 nm DCR ~ 5 mcps/mm 2 at 80 K Higher over-voltage operation The signal from the 4 x 6 cm 2 quadrants is summed with an active adder arxiv:1706:04220 Full 24 cm 2 tile with NUV-HD-LF at LN2 5 VOV: σ1pe = 9% μ1pe SNR = 13 1PE Time resolution: 16ns Total power dissipation ~ 170 mw Dynamic range > 0 PE See poster by A. Mandarano 17

18 Ultra-low background Low-Mass Searches 38 [ cm 2 ] 39 σ SI 90% CL upper l i mi t on DS50 Expected Limit mbq/kg Ar, 2 mbq/pdm mbq/kg Ar, 2 mbq/pdm mbq/kg Ar, 0.2 mbq/pdm NEWS-G 2018 LUX 2017 XENON1T 2017 PICO PICASSO 2017 CDMSLite 2017 CRESST-III 2017 PandaX-II 2016 XENON DAMIC 2016 CDEX 2016 CRESST-II 2015 SuperCDMS 2014 CDMSlite 2014 COGENT 2013 CDMS 2013 CRESST 2012 DAMA/LIBRA 2008 Neutrino Floor 1 2 [GeV/c ] 1 year data taking with DS-Proto M χ

19 ReD low energy calibrations and directionality in Liquid Argon

20 ReD TPC Designed and built at UCLA Optimized for neutron beam tests Assembled at Naples CRYOLAB In its dedicated LAr cryosystem B. Bottino and M. Caravati

21 Photoelectronics 2 5 5cm 2 tiles 24 NUV-HD-LF rectangular SiPM, 25 µm cell, MOhm quenching resistor, Arlon substrate TOP new 24 channels FEB BOTTOM 4 channels FEB

22 First data Beam starting from July

23 Scalability: a LAr shield for DarkSide-20k AAr in ProtoDune style large cryostat to provide shielding and active VETO Benefitting from an important technological contribution from CERN allowing to eliminate Liquid Scintillator Veto and Water tank Significantly simplify the overall system complexity and operation Fully scalable design for future larger size detector (300 ton)

24 CERN Neutrino Platform: Two almost identical cryostats built for NP02 and NP04 experiments About 8x8x8 m 3 inner volume, 750 t of LAr in each one Cryostat technology and expertise taken from LNG industry Construction time: 55 weeks (NP04), 37 weeks (NP02) Thought since the beginning to be installable underground

25 DarkSide-20k sensitivity ] 2 WIMP-nucleon σ SI [cm Neutrino floor DarkSide-50 (2018) DEAP-3600 (proj.) LZ (proj.) WARP (2007) DarkSide-50 (2015) DEAP-3600 (2017) LUX (2017) XENON1T (proj.) PANDAX-II (2017) XENON1T (2017) XENONnT (proj.) DarkSide-20k (0 t yr proj.) DarkSide-20k (200 t yr proj.) Future 300-tonne GADMC Detector (1kt yr proj.) Future 300-tonne GADMC detector (3kt yr proj.) WIMP mass [TeV/c ] 25

26 Summing up 38 [ cm 2 ] 39 σ SI 90% CL upper l i mi t on DS50 Expected Limit mbq/kg Ar, 2 mbq/pdm mbq/kg Ar, 2 mbq/pdm mbq/kg Ar, 0.2 mbq/pdm NEWS-G 2018 LUX 2017 XENON1T 2017 PICO PICASSO 2017 CDMSLite 2017 CRESST-III 2017 PandaX-II 2016 XENON DAMIC 2016 CDEX 2016 CRESST-II 2015 SuperCDMS 2014 CDMSlite 2014 COGENT 2013 CDMS 2013 CRESST 2012 DAMA/LIBRA 2008 Neutrino Floor

27 Conclusions DARKSIDE: An ambitious program for discovery of dark matter Technology developed to achieve Zero Background and scalability DarkSide-50 sensitive to 1- GeV WIMPs and sub- GeV DM-electron scattering DarkSide-20k set to start in 2021, with a projected sensitivity of 1-47 cm 2 for a 1 TeV/c 2 dark matter particle mass and an exposure of 0 tonne yr Global Argon Dark Matter Collaboration aiming at 1,000 tonne year search for dark matter 27

28 LNGS Hall C THANK YOU