Low Radioactivity Argon for Dark Matter and Rare Event Searches

Rahaf Ajaj, PhD On behalf of the Global Argon Dark Matter Collaboration (GADMC) The 29th International Symposium on Lepton Photon Interactions at High Energies 5th – 10th August 2019 Toronto, ON, Canada Lison Bernet – Moriond 2019 2019-08-02 Rahaf Ajaj, PhD 2 Content

• DarkSide Program • Current Experiments • Future Projects & Experiments. • Summary

2019-08-02 Rahaf Ajaj, PhD 3 DarkSide

• DarkSide Program. • Global Argon Dark Matter Collaboration. • 420 Researchers from 59 institutions and 14 countries. • Current experiments: DS-50, DEAP, ArDM, MiniClean. • Future experiments: DS-20K, ARGO. • Labs: LNGS, SNOLAB, LSC & CERN.

2019-08-02 Rahaf Ajaj, PhD 4 Why Liquid Argon?

Efficient Scintillator

Relatively Unsurpassed NR & EM inexpensive discrimination LAr

WIMP masses High > 30 GeV/c2 Ionization Excellent Sensitivity Yield with single/two phase detection Exceptional Radioactivity & Chemistry

Low radon backgrounds (160 nBq/kg of 222Rn, 2.6 220 2019-08-02 nBq/kg of Rn in DEAP3600) 5 Rahaf Ajaj, PhD Phys. Rev. D 93, 081101 (2016) Current Experiments

•Dark matter Experiment •Argon Dark Matter target using Argon Pulse-shape 850 Kg LAr. discrimination. •Only measured AAr, using •Single-phase liquid a fiducial region of the Argon (LAr) scintillation inner 200 litres. light detector, holding •Nowadays taking data in 3279 Kg at SNOLAB. dual phase. at LSC. ArDm DEAP •Most sensitive WIMP •Will be used as an active masses > 70 GeV/c2. veto for future experiments (DArT/DarkSide-20k).

•Single phase detector •Dual-phase argon time utilize 500 kg of LAr. projection chamber . •Fiducial mass region of •Presently it is filled with of 150 Kg UAr. •Uses 92 sensitive •World’s most sensitive for photodetectors. WIMP mases in the range of MiniClean •Operating at SNOLAB DarkSide-50 (1.8 GeV/c2 - 6.0 GeV/c2). since 2013. •39Ar depletion factor 1400. 2 -43 cm x10 2 - 3.43 -44cm 3.78x10

2 -44 cm 1.5x10

2019-08-05 Rahaf Ajaj, PhD 7 Why UAr

• Challenge: Argon radioisotopes; 39Ar (1 Bq/Kg), 42Ar (68µBq/Kg). • Mantle gas has the lowest 39Ar production. • Geological formation trap gasses underground.

• Argon source: CO2 well in southwest Colorado (400 ppm Ar). • DS-50: 39Ar = 0.73 mBq/Kg o 1400x reduction from AAr. o Low production o Suspected contamination with AAr.

2019-08-04 Rahaf Ajaj, PhD 8 DarkSide Target

Maximize the DM discovery potential with background free detectors How?

Increment the production rate of UAr (Urania) Further purification after extractions (Aria) 39Ar reduction by the factor of 15,000 (DS-20K) Reach beyond the sensitivity corresponding to the “neutrino floor” (ARGO)

ARGO DS-20K

• Volatilità relative => 1.007

• Valori tipici >1.5 Thousands of equilibrium stages reflects in a very tall column Preliminary lay-out • Numero di stadi teorici => ordine delle migliaia 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270 280 290 300 310 320 330 340 350 360 370 380 390 400 410 420 430 440 450 460 470 480 490 500 510 520 530 540 550 560 570 580 590 600

• HETP = 10 cm R&D Column Seruci Wells30 cm diameter • H=200-400 m 350ARIA m height • Usuali = 20-30 m URANIA

• Fuori terra 325 m • A sezioni separate2019 -08-02 Rahaf Ajaj, PhD 9

10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270 280 290 300 310 320 330 340 350 360 370 380 390 400 410 420 430 440 450 460 470 480 490 500 510 520 530 540 550 560 570 580 590 600

a^er POLARIS Srl URANIA

• Target: extract and purify low-radioactivity UAr at a rate of 330 Kg/day with purity of better than 99.99%. o 50 tonne to fill DS-20K (LNGS 2022-2023). o 400 tonne to be stored at SNOLAB (ARGUS). o Future larger detector (ARGO – collecting argon 2022-2029). • Source: Doe Canyon , Cortez, CO.

• Urania feed : ~ 95% CO2 + few percent N2 + 1% CH4 + 430 ppm of UAr + traces of hydrocarbons.

• Shipping/Transportation: Phase 1 (DS-20PreliminaryK) & lay-outPhase 2 (ARGUS) • Operation: October 2021. • Storage: ARGUS – SNOLAB. 2019-08-02 Rahaf Ajaj, PhD 10 Concept Design of URANIA

a^er POLARIS Srl Gas Sampling & Analysis

Preliminary lay-out Urania Feed from URANIA PLANT

Back to URANIA PLANT

Max 15 psi

a^er POLARIS Srl Gas Container Max Pressure 100 – 200 psi Gas to RGA System Max Temp PC 75° - 200°C

Cirrus 3-XD To Cirrus 3-XD Heated Capillary Inlet,

Pressure < 1000 Torr

The 16 channel multi-stream rotary valve & actuator at CU

2019-08-02 Rahaf Ajaj, PhD 11 ARIA

• Goal: Purification for UAr to get detector grade Ar, free from N and other impurities. • Two cycles are needed for separation of light and heavy components. Concept Design of Aria • Production in chemical mode (DS- 20K): 1tonne/day. • Commissioning scheduled by Q2 of 2020 in Sardinia, Italy.

ARIA- Distillation Plant 2019-08-02 Rahaf Ajaj, PhD 12 DArT

• DArT is a small (∼1 L) chamber that will measure the depletion of 39Ar in UAr (URANIA/ARIA). • Aiming 20% precision in a week for DF 1400 without lead shield. With lead shield 7%. ArDM • The detector will be immersed in the LAr active volume of ArDM (active vito) • Will be installed at the LSC and commissioned in the Q4 of 2019.

DArT 13 2019-08-02 Rahaf Ajaj, PhD DarkSide-20K

• Next generation LAr detector for WIMP searches. • Consists of two detectors (inner & veto). • Operate with 50 tonne low radioactivity underground argon (UAr). • Membrane cryostat filled with ~700 tonnes of AAr. • Designed to reach an exposure of 100 tonne-year in background-free mode (less than 0.1 events of background). Concept Design of DarkSide-20K • Will be located at LNGS and commissioned by ~2023.

2019-08-02 Rahaf Ajaj, PhD 14 Projected Sensitivity – DS-20K

σ= 9x10-48 @ 1 TeV/c2 , σ = 9x10 -47 @ 10TeV/c2

2019-08-02 Rahaf Ajaj, PhD 15

PHYSICAL REVIEW LETTERS 121, 081307 (2018), ARGO

• Target: Most sensitive WIMP search. • Aims to reach beyond the sensitivity corresponding to the “neutrino floor” in DM searches • Operate with ~400 tonne detector free of background UAr. • Planning for 300 tonne (fiducial) for 3 ktonne-year free of background. • Will be commissioned by ~2029.

Concept Design of Argo

2019-08-02 Rahaf Ajaj, PhD 16 ARGO, continued

• Currently exploring detailed design, including experience from progenitor experiments (both single- phase S1-only and dual-phase TPC). • Conceptual design underway for other backgrounds (cosmogenic-related, neutrons, Cherenkov, etc.) • Possibility of intermediate-energy solar neutrino measurements; ktonne-year exposure allows very sensitive measurements. • Exploring the possibility of other physics measurements by reconfiguring the detector (e.g. addition of xenon or other gases) for sensitivity to other WIMP models or parameter space.

2019-08-04 Rahaf Ajaj, PhD 17 Projected Sensitivity - ARGO

σ= 9x10-49 @ 1 TeV/c2 , σ = 9x10-48 @ 10 TeV/c2 2019-08-02 Rahaf Ajaj, PhD 18

PHYSICAL REVIEW LETTERS 121, 081307 (2018), Summary

•GADMC is aiming to maximize the DM discovery potential. •UAr is promising technology for the future DM detectors. •DArT is a small chamber will be installed in ArDM at LSC to measure the depletion of 39Ar in Q4 of 2019. •Aria will do the chemical purification for UAr for 39Ar depletion in Sardinia in Q2 of 2020 •Urania plant will be ready for operation October 2021 and the first 50 tonne production July 2022 •ARGUS is the UAr storage facility will be located in SNOLAB. •DS-20K is the next generation of LAr detector will be located at LNGS and commissioned by 2023. •ARGO is the longer term objective of the GADMC aims to be the most sensitive WIMP search detector commissioned by ~ 2029, Preferred location SNOLAB. 2019-08-02 Rahaf Ajaj, PhD 19 Thank You!

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