Noble Liquid Detectors - SOUP 20|21 - Cristiano Galbiati - July 1, 2021 - CERN Indico

Noble Liquid Detectors
SOUP 20|21

Cristiano Galbiati - July 1, 2021

Noble Liquid Detectors
 • Target = Detecto
 • Excellent scintillation detectors: 40 photons/keV (Ar, 128
 nm ), 46 photons/keV (Xe, 178 nm
 • Excellent ionization detectors: 40 electrons/keV (Ar), 64
 electrons/keV (Xe)
 • Photons and electrons not self-absorbe
 • Easily puri e
 • Excellent background discriminatio
 • Large multi-ton detectors possible and “cheap”
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TPC in Action
 primary scintillation photons secondary photons emitted by
 emitted and detected multiplication in gas region
 extraction and
 gaseous Ar/Xe
 acceleration
 multiplication grids
 eld (~3 ionized
 kV/cm) electrons drifted
 eld-shaping X
 to gas region
 rings
 drift eld (~1
 liquid Ar/Xe kV/cm)
 WIMP Scatte transparent
 deposits inner vessel
 energy in FV
 photodetectors (QUPIDS) ducial volume boundary
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Discrimination in Xenon
 • Fiducialization reduces the background from
 construction and external materials in the ducial
 regio
 • Difference in ratio of the prompt scintillation (S1) to
 the drift time-delayed ionization (S2) with strongly
 dependent upon recombination of ionizing tracks,
 which in turn depends on ionization densit
 • Rejection ~ 102-10
 • Precise determination of events location in 3D
 • 1-5 mm x-y, 1 mm
 • Additional rejection for multiple neutron recoils and
 γ background
 3

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Discrimination in Argon
• Pulse shape discrimination of primary scintillation (S1)
 based on the very large difference in decay times
 between singlet (≈ 7 ns) and triplet (1.6 µs)
 components of the emitted UV ligh
 Minimum ionizing: triplet/singlet ~ 3/
 Nuclear recoils: triplet/singlet ~ 1/
 Theoretical Identi cation Power exceeds 108 for >
 60 photoelectrons (Boulay & Hime 2004
• Difference in ratio of the prompt scintillation (S1) to
 the drift time-delayed ionization (S2)
• Precise determination of events location in 3D
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WARP Collaboration
 INFN and Università degli Studi di Pavi
 P. Benetti, E. Calligarich, M. Cambiaghi, L. Grandi
 C. Montanari, A. Rappoldi, G.L. Raselli, M. Roncadelli
 M. Rossella, C. Rubbia, C.Vignol

 INFN and Università degli Studi di Napol
 F. Carbonara, A. Cocco, G. Fiorillo, G. Mangan

 INFN Laboratori Nazionali del Gran Sass
 R. Acciarri, F. Cavanna, F. Di Pompeo, N. Ferrari,
 A. Ianni, O. Palamara, L. Pandol

 Princeton Universit
 F. Calaprice, H. Cao, A. Chavarria, C. Galbiati
 B. Loer, P.Mosteiro, A. Nelson, R. Saldanh

 IFJ PAN Krako
 A.M. Szel

 INFN and Università degli Studi di Padov
 B. Baibussinov, S. Centro, M.B. Ceolin
 G. Meng, F. Pietropaolo, S.Ventura
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First Two Discrimination Methods
 (A) Electron
 S2 (B) Argon recoil
 S2
 S1 S1
 Drift time

 S1 S1

Events are characterized by
 the ratio S2/S1 between the primary (S1) and secondary (S2
 the rising time of the S1 signa
Minimum ionizing particles: high S2/S1 ratio (~100) and by slow S1 signa
Ar recoils: low (≤10) S2/S1 ratio and fast S1 signal
 :

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First Dark Matter Results

 Selected events in the n-induced single
 recoils window during the WIMP search run
 Non
 Astropart. Phys. 28, 495 (2008)
e

 :

WARP 140-kg Detector
 The WARP 140-kg detector, currently under
 commissioning at LNG
 140 kg active target, to reach into 5x10-45 cm2 100 liters Chamber

 and cover critical part of SUSY parameter Active Veto

 spac
 Complete neutron shield
 4π active neutron veto (9 tons Liquid Argon,
 300 PMTs
 Active control on nuclide-recoil background,
 owing to unique feature (LAr active veto
 3D Event localization and de nition of ducial
 volume for surface background rejectio
 Detector designed for positive con rmation
 of a possible WIMP discover
 Cryostat designed to allocate a possible 1400
 kg detector Passive neutron and gamma shield
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Construction completed in July 200
 First run in August 200
 Obtained light yield of 1.6 ph.el./keVee
Drained in Sep 2009 to x problem with HV cabl

 Restart Dec 200

 140 kg active mas
 2 ph.el/keVee
 55 keVr threshol
 background-free for 6 month
 sensitivity 10-44 cm2
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 9

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DARKSIDE
 12
 DARKSIDE-50
 Radon-free (Rn levels < 5 mBq/m )
 3

 Assembly Clean Room

 1,000-tonne Water Cherenkov
 Cosmic Ray Veto

 30-tonne Liquid Scintillator
 Neutron and γ’s Veto
 Veto ef ciency > 99.1%

 Inner detector TPC
 lled with 150 kg of liquid
 Underground Ar
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PSD AND LOW RADIOACTIVITY ARGON

DARKSIDE-50 1
 20 40 60 80 100 120 140
 Energy [keVnr]
 160 180 200

 f90
 0.9 25000

 PLB 743, 456 (2015)
 0.8

✓ ER/NR Discrimination
 50% 65% 20000
 0.7 80% 90% 95%
 99%

 0.6
 ‣ PSD vs S1 for 1422 kg d atmospheric 0.5
 15000

 argon (AAr) exposure 0.4
 10000
 0.3
 ‣ 1.5x107ER events from 39Ar activity in 0.2 5000
 AAr and Zero NR events 0.1

 0 0
 50 100 150 200 250 300 350 400 450

✓ Suppression: AAr Vs UAr S1 [PE]

 ‣ 39Ar production supported by
 cosmogenic activation via

 PRD, 93 (2016): 081101(R)
 40Ar(n,2n)39Ar

 ‣ Underground argon (UAr): 150 kg
 successfully extracted from a CO2 well
 in Colorado
 39Arin UAr
 ‣ 39Ar depletion factor >1400 < 1 mBq/kg

HIGH MASS WIMP SEARCH 14
 10−41

540-DAY BLIND ANALYSIS RESULT (20
 07)

 WIMP-nucleon σSI [cm 2]
 W ARP
 −42
 10 15)
 0 (20
 -5 7)
 k S ide (201
 Dar -3600
 10−43 DEA
 P

Strong Pulse Shape Discrimination!!
 8)
 50 (201
 ide- 17)
 10−44 Dark
 S (20
 LUX
 18)
 (20
 O N1T
 XEN
 10−45

 No BG in the Search Region
 17)
 I (20
 DA X-I
 PAN
 10−46

 Energy [keVnr] 10−2 10−1 1
 WIMP mass [TeV/c2]
 10

 0 20 40 60 80 100 120 140 160 180 200
 1
 500
 Pulse Shape Discrimination

 0.9
 WIMP Search Region
 0.8 1%
 400
 50%
 0.7
 99%
 0.6 300
 0 EVENT
 f90

 0.5

 0.4 200
 0.3

 0.2 100

 0.1

 0 0
 0 50 100 150 200 250 300 350 400 450
 S1 [PE]
 Phys. Rev. D 98 102006 (2018)

LOW MASS WIMP SEARCH
 15
 S2-ONLY RESULT ▸ Ionization signal (S2): threshold

FUTURE DETECTOR

DARKSIDE-20K IN LNGS HALL-C
 AAr cryogenics
 Feedthroughs DAQ UAr Test cryostat /
 Calibration cryogenics UAr liquid recovery

 TPC assembly TPC staged in
UAr gas storage AAr cryostat Veto panels TPC Faraday cage fixture clean room

FUTURE DETECTOR
 17
 DARKSIDE-20K

 ▸ A 20-tonnes ducial argon detector
 FIG. 2. A cross section of the DarkSide-20k TPC, and details of its anode and cathode regions. Particles
 (e.g., WIMPs) interact with the liquid argon (LAr) target producing prompt scintillation (S1). Ionization
 lled with underground argon
 electrons, also produced at the interaction site, are drifted to the anode by a uniform electric field, Edrif t ,
 where they are extracted into a thin gas pocket and accelerated to produce a second, delayed signal (S2) via
 electroluminescence. The time interval between S1 and S2 provides the depth of the event along the detector
 axis, while the transverse position is determined via S2 using the top array of photodetectors.
 ▸ TPC acrylic vessel surrounded by AAr +
 PDM

 185 a profile-likelihood ratio analysis using the full 49.7 t active volume of the detector over the full
 186 500 t yr exposure [26].
 Gd-loaded acrylic shell as a neutron veto
 187 Background Rejection Features: As exposure increases, argon-based detectors feature several
 188 experimental advantages that make them immune from the background sources expected to a↵ect
 189

 190
 their xenon-based counterparts.
 ▸ 21 m2 of Cryogenic Silicon based
 Radon: Due to its low boiling point and small atomic size, argon can be efficiently purified
 191

 192
 Photo-Multipliers
 with charcoal traps, as demonstrated by the record-low 222Rn and 85Kr contamination levels ob-
 served in large LAr detectors [20, 27]. For example, DEAP-3600 measured 222Rn concentrations of
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PHYSICS POTENTIAL

EXCLUSION SENSITIVITY AND 5σ DISCOVERY POTENTIAL

 FIG. 3. The sensitivity of DS-20k to spin independent WIMPs (top: 90% C.L. exclusion; bottom: 5
 significance) for di↵erent lengths of runs shown with the sensitivity of LZ (2.7 yr run, 15.3 t yr exposure [31])
 and XENONnT (5 yr run, 20.2 t yr exposure [32]). The region excluded by XENON1T [8] is shown in shaded

▸ Expect 3 events in 200 ton x year from neutrino coherent scattering
 green, the “neutrino floor” in shaded gray [33], and the turquoise filled contours represent the 1-, 2-, and 3-
 favored regions from the pMSSM11 model constrained by astrophysical measurements and the ⇠36 fbarn
 LHC data at 13 TeV [34]. (Note: the XENONnT 90% C.L. exclusion curve shown in these plots use a
 two-sided test statistic, leading to limits weaker by 30%, as described in Ref. [32].)

▸ Underground Argon target, excellent PSD, and neutron veto allow 6
 zero instrumental background

FUTURE DETECTOR
 19
 ARGO
 ▸ ArDM, DS-50, DEAP-3600, and MiniCLEAN jointly formed the Global Argon Dark
 Matter Collaboration (GADMC)

 ▸ A 300-tonnes ducial argon detector lled with underground argon

 ▸ 3000 tonne×year exposure to reach the neutrino oor

 10−37 CR
 ES
 −38 ST
 10 CD -I
 MS II
 Dark Matter-Nucleon σSI [cm2]
 −39 Li
 10 te 20
 19
 20
 10−40 17

 10−41 Da
 rk 2017
 Si ATLAS 2018 (Vector Z', 95% CL) 600
 P-3
 10−42 de DEA
 -5 2019
 0
 P-3600
 −43 20 DEA
 10 18 18 2017
 SuperC
 DMS pr 50 2 0 LU X 2017.
 oj. id e - X-II proj
 10−44 Dar kS
 1 8
 NDA
 PA -3600
 DarkSi
 de-LM N1 T 20 DEAP
 10−45 proj. XENO
 Z proj.
 L
 10−46 T proj..
 XENt ONn r proj
 y
 10−47 2 00 × j.
 -20×k pro
 Si de t yr .
 DarkIN 200 yr proj
 10−48 DARW 3000 t×
 Argo
 10−49 Neutrino floor on xenon
 10−50
 10−3 10−2 10−1 1 10 102
 M χ [TeV/c2]

 GADMC experiments cover the WIMP hypothesis from 1GeV/c2 to several hundreds of TeV/
 c2 masses in the search for spin-independent coupling.
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LOW RADIOACTIVITY ARGON

 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 nal chemical
 puri cation at Aria

 ARIA
 ▸ Big cryogenic distillation column in Seruci, Sardinia
 ▸ Final chemical puri cation of the UAr
 ▸ Can process O(1 tonne/day) with 103 reduction of
 all chemical impurities
 ▸ Ultimate goal is to isotopically separate 39Ar from
 40Ar (at the rate of 10 kg/day in Seruci-I)
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The Urania project@Kinder Morgan Doe
Canyon Facility, CORTEZ,CO (USA)

extraction of 65t of UAr from CO2 deep
wells, from the upper earth mantle,
where cosmic rays hardly make any
39Ar; nucleogenic 39K(n,p)40Ar though to

be dominant

Starting from 95% CO2 and 440ppm of
UAr and aiming at 99.99% purity!

Three gas processing units followed by
cryogenic distillation unit

Production rate of 330 kg/day
 Walter Bonivento11 @TAUP, Sep 2019 TAUP-Toyama-2019

The Aria plant was designed to perform isotopic separation of 39Ar from 40Ar using a 350m
cryogenic distillation column, 30cm diameter, operated in continuous mode

The working principle exploits the different volatility of the two isotopes

with α being the vapour pressure ratio between the two isotopes

The columns can perform factor 10 suppression at 10kg/day

 Walter Bonivento14 @TAUP, Sep 2019 TAUP-Toyama-2019

™

2000 a.c. 2000 b.c.

 Walter Bonivento16 @TAUP, Sep 2019 TAUP-Toyama-2019

Walter Bonivento18 @TAUP, Sep 2019 TAUP-Toyama-2019

28m

Walter Bonivento19 @TAUP, Sep 2019 TAUP-Toyama-2019

Walter Bonivento20 @TAUP, Sep 2019 TAUP-Toyama-2019

Innovative design: total
 recovery of the cooling liquid
 (nitrogen) and low power
 consumption due to enhanced
 heat recovery

 structured stainless steel
 packing type called Sulzer CY
 gauze
Walter Bonivento21 @TAUP, Sep 2019 TAUP-Toyama-2019

™
Walter Bonivento22 @TAUP, Sep 2019 TAUP-Toyama-2019

Walter Bonivento26 @TAUP, Sep 2019 TAUP-Toyama-2019

Walter Bonivento27 @TAUP, Sep 2019 TAUP-Toyama-2019

Walter Bonivento31 @TAUP, Sep 2019 TAUP-Toyama-2019

nEXO’s TPC design updates

Monolithic detector volume
 - >3 ton (~1028 atoms) fiducial
 volume
 - Powerful self-shielding Charge collection
 - Measure backgrounds directly in tiles at anode
 the same detector
Advanced scintillation readout 
 - VUV-sensitive SiPMs Photon detectors
Custom tiled charge readout (SiPMs) on walls

 - Lower radioactivity, modular
 construction compared to wires High voltage field
 cage
In-liquid-xenon, cold electronics
 - Low-background ASICs for both
 light and charge readout Cathode

Brian LenardoBrian Lenardo
 NeuTel 2021 Feb 23, Feb
 @Neutrino Telescopes, 2021 2021 7

Charge readout 10
 cm

Gold strips on quartz substrate
 - 6mm pitch
 - 3mm prototype tested: Jewell et al. JINST 13 (2018)
In-LXe cold electronics
 - Lower noise, smaller cable capacitance
 - Stringent radioactivity & power requirements
 - Custom ASICs under development
Advanced reconstruction techniques under study
 Li et al., JINST 14 (2019)

 Calibration of prototype with 207Bi

Brian LenardoBrian Lenardo
 NeuTel 2021 Feb 23, Feb
 @Neutrino Telescopes, 2021 2021 8

Scintillation readout

nEXO will use VUV-sensitive SiPMs for
scintillation readout
 - Lower noise than APDs in EXO200
 1 x 1 cm
 - Better radiopurity than PMTs

Relatively new technology -- extensive R&D and nEXO Correlated noise vs. detection
characterization ongoing within collaboration goal efficiency for FBK SiPMs

 - Photon detection efficiency, noise properties
 - Ostrovskiy et al., IEEE TNS 62 (2015)
 arXiv:1502.07837
 - Jamil et al., IEEE TNS 65 (2018) arXiv:1806.02220
 - Gallina et al., NIM A 940 (2019) arXiv:1903.03663

 - Development of in-LXe ASIC readout
 Jamil et al., IEEE TNS 65 (2018)

Brian LenardoBrian Lenardo
 NeuTel 2021 Feb 23, Feb
 @Neutrino Telescopes, 2021 2021 9

Estimating radioactive backgrounds
 Extensive materials screening campaign, following success of EXO-200 (e.g. D. Leonard, NIMA 591 (2008) )

 Essentially every material in existing design has been screened for radiopurity
 → nEXO background model is conservative and data-driven

 ROI background rate by detector component ROI background contribution by source

Brian LenardoBrian Lenardo
 NeuTel 2021 Feb 23, Feb
 @Neutrino Telescopes, 2021 2021 10

Expected performance - Geant4 simulation
 Single-site (SS) events Multi-site (MS) events
 in full volume in full volume

 Region of
 interest (ROI)

 3000 2000 1000 Liquid xenon mass (kg)

 27
 SS standoff distance in ROI
 (5.7x10 yr)

 Distance from detector walls (mm)

Brian LenardoBrian Lenardo
 NeuTel 2021 Feb 23, Feb
 @Neutrino Telescopes, 2021 2021 11

Projected physics reach ca. 2018

 5.7 x 1027 yr

 90% confidence limit

 3 discovery potential EXO-200 combined limit
 Accepted by PRL (2019)
 EXO-200 90% limit

 EXO-200 full exposure: 3.5 ✕ 1025 yr

Projected sensitivity: T1/2 > 9.2e27 yr @ 90% CL
 - J. Albert et al., PRC 97, 2018

 Brian LenardoBrian Lenardo
 NeuTel 2021 Feb 23, Feb
 @Neutrino Telescopes, 2021 2021 12

Recent improvements in readout simulations
 Charge reconstruction of 0nuBB event with a bremsstrahlung
Charge readout modeled
end-to-end
 - Full noise simulation of ASIC readout
 and charge propagation through TPC
 - Induction and noise signals generated to
 mimic real data
 - Z. Li et al. (NEXO) JINST 14 (2019)
 - Machine learning classifier likely to
 improve signal/bkg discrimination

Light collection modeling improved
with new data and software
 - High-stats, fine-grained simulation using
 GPU-based Chroma software
 - New measurements of SiPM optical properties
 and performance
 - P. Nakarmi et al. (NEXO) JINST 15 (2020)
 - G. Gallina et al. (NEXO) NIMA 940 (2019)
 - A. Jamil et al. (NEXO) IEEE TNS 65 (2018)
 - P. Lv et al. (NEXO) IEEE TNS 67 (2020)
 - M. Wagenpfeil et al. (NEXO) In preparation

 - Improvements in projected light collection based
 on new data

 Brian LenardoBrian Lenardo
 NeuTel 2021 Feb 23, Feb
 @Neutrino Telescopes, 2021 2021 13

Avenues for further background reduction
 ROI background rate by detector component
 TPC Vessel
Improved construction materials Charge module cables
 Field rings
 - Underground electroformed copper SiPM cables

 (pioneered by MJD) could reduce copper SiPM support

 radioactivity by x20 and x4 for 238U and
 232
 Th respectively
 - Better polyimide cables identified, with
 x3 (x5) reduction in 232Th (238U) activity
 Charge module support
 - Reduces several big contributors to
 gamma-ray backgrounds

 SS standoff distance in ROI Active cosmogenic veto
 - Recycled Daya Bay PMTs could
 instrument water shield
 - Muon tagging via Cherenkov
 light detection
 - Reduces 137Xe β-decay bkg;
PMT’s added in water tank largest in innermost LXe

 Brian LenardoBrian Lenardo
 NeuTel 2021 Feb 23, Feb
 @Neutrino Telescopes, 2021 2021 14

How to confirm experimentally if neutrino is a Majorana particle?
 ββ0ν in high-pressure 136Xe gas

 e-
 e-

 Ba ++

 2

How to confirm experimentally if neutrino is a Majorana particle?
 ββ0ν in high-pressure 136Xe gas

 Ba ++

 3

luorescent Bicolour Indicator BOLD
 O
 FBI·Ba++
 O O
 FBI
 N O
 O O
 O
sensing in solution

 O
 N Ba++ O
 FBI FBI O
 Ba++
 N
 N N
 N

 Excitation: 365 nm
Ba++

 "Fluorescent bicolour sensor for low-background neutrinoless double β decay experiments", Nature 2020, 583, 48-54. 9

luorescent Bicolour Indicator BOLD
 FBI deposited
 on silica pellet
sensing in high-vacuum
Ba++

 "Fluorescent bicolour sensor for low-background neutrinoless double β decay experiments", Nature 2020, 583, 48-54. 11

luorescent Bicolour Indicator BOLD
 FBI FBI·Ba++
 Excitation: 365 nm Excitation: 365 nm
Ba++ sensing in high-vacuum

 0
 d FBI·Ba2+
 20
 λ = 400-425 nm
 blue filter 40
 λ = 400-425 nm

 Z (µm)
 60
 80

 0 50 100 150 200 250
 X (µm)
 DFT-computed Gibbs reaction energies
 0
 e FBI·Ba2+
 20 λ > 450 nm
 green filter
 λ > 450 nm
 40 FBI + Ba(ClO4)2 FBI·Ba(ClO4)2

 Z (µm)
 60
 80 ΔGrx = -90 kcal/mol
 0 50 100 150 200 250
 X (µm)
 2 Photon Absorption Microscopy (excitation at 800 nm) FBI + Ba++·8Xe FBI·Ba++ + 8Xe

 ΔGrx = -195.9 kcal/mol
 FBI sensors capture Ba++ in dry phase!

 "Fluorescent bicolour sensor for low-background neutrinoless double β decay experiments", Nature 2020, 583, 48-54. 12

luorescent Bicolour Indicator What’s NEXT @ BOLD ?
 ”BOLD” concept with fully active cathode, SiPM-based tracking and Energy Barrel Detector

 "Fluorescent bicolour sensor for low-background neutrinoless double β decay experiments", Nature 2020, 583, 48-54. 13

The End