Low Radioactivity Argon for Dark Matter and Rare Event Searches
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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
Yield
Sensitivity with single/two
phase
detection
Exceptional
Radioactivity
& Chemistry
Low radon backgrounds (160 nBq/kg of 222Rn, 2.6
nBq/kg of 220Rn in DEAP3600)
2019-08-02 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 •Will be used as an active
DEAP •Most sensitive WIMP
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
3. 43 x10
2 -
0-4 cm
4
3. 78x1
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
ousands of equilibrium stages reflects in a very tall column
•Numero di stadi teorici => ordine delle migliaia
Preliminary lay-out
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
Seruci Wells
R&D Column
30 cm diameter
•H=200-400 m
•Usuali = 20-30 m
350 m height
ARIA URANIA
325 m
•Fuori terra
•A sezioni separate 2019-08-02 Rahaf Ajaj, PhD 9
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
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-20K) & lay-out
Preliminary Phase 2
(ARGUS)
• Operation: October 2021.
• Storage: ARGUS – SNOLAB.
2019-08-02 Rahaf Ajaj, PhD 10
Concept Design of URANIA
a^er POLARIS SrlGas 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 11ARIA
• 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 12DArT
• 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, PhDDarkSide-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 14Projected 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 16ARGO, 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 17Projected 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! 2019-08-02 Rahaf Ajaj, PhD 20
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