THEIA: AN ADVANCED OPTICAL NEUTRINO DETECTOR - ZARA BAGDASARIAN FOR THE THEIA COLLABORATION UNIVERSITY OF CALIFORNIA, BERKELEY NUSTEC WORKSHOP ...

THEIA: An advanced optical neutrino detector

 Zara Bagdasarian for the THEIA collaboration
 University of California, Berkeley

 NuSTEC workshop
 March 18th 2021

Theia: advanced optical multipurpose neutrino detector
 Design options

 Broad physics program:
 Cutting edge Theia-25 Studying neutrino
 developments in the
 fundamental properties
 target material and
 and astrophysical
 photodetection
 objects
 Theia-100 Large scale, multipurpose
 detector
 • Baseline: 25ktonne (17kt FV)
 • Ideal: 100 ktonne (70kt FV)

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 THEIA: An advanced optical neutrino detector Eur. Phys. J. C 80, 416

Theia: advanced optical multipurpose neutrino detector
 Design options

 Broad physics program:
 Cutting edge Theia-25 Studying neutrino
 developments in the
 fundamental properties
 target material and
 and astrophysical
 photodetection
 objects
 Theia-100 Large scale, multipurpose
 detector
 • Baseline: 25ktonne (17kt FV)
 • Ideal: 100 ktonne (70kt FV)

 3
 THEIA: An advanced optical neutrino detector Eur. Phys. J. C 80, 416

How to broaden the current physics reach
 Scintillation Detectors: Cherenkov Detectors:
 ✅ High light yield ✅ Directional information
 ✅ Low energy threshold ✅ Can be very large (low
 ✅ Good energy and position absorption)
 resolutions ✅ Particle ID at high energies
 Limited in size by absorption No access to physics below
 and cost the Cherenkov threshold
 No directionality Low light yield

 Water-based Liquid Scintillation (WbLS) Detectors: Get best of two worlds

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Water-based Liquid Scintillator - Basics
• Water-based Liquid Scintillator (WbLS) is a mixture of
 pure water and oil-based liquid scintillator

• WbLS is made using a surfactant (soap-like) such as
 PRS* (hydrophilic head and hydrophobic tail) to hold the
 scintillator molecules in water in a “micelle” structure
 125
• Combines the advantages of water (transparency, low

 Attenuation length [m]
 cost) and liquid scintillator (high light yield) Water
 (Super-K,
 SNO)

 75

 Water-like Oil-like
 Cost-effective,
 Loading of hydrophilic
 environmentally-
 elements
 friendly

 25
 Scintillator
 (Borexino,
 KamLAND)

 102 103 104 5
 Light yield [p.e./MeV]

Water-based Liquid Scintillator - Advanced
Developed Water-based Liquid Scintillator (WbLS) Other relevant developments
cocktails require extensive characterization: • Nano ltratio
 • Light Yield • Advanced reconstruction techniques, including
 • Emission spectrum machine learnin
 • Scintillation time pro le • Cherenkov/Scintillation separation
 • Scattering and attenuation lengths demonstration

 UC Davis

 Munich

 Mainz Berkeley
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 :

Cherenkov/scintillation photons separation
Cherenkov (Č) Angular distribution Timing Wavelength

 Angular resolution
 Large area picosecond • Dichroic lters
 photodetectors LAPPDs • Red-sensitive PMTs
Scintillation (~70 ps TTS) or other • Filtering
 fast photodetectors

 T. Kaptanoglu et al.
 B.W.Adams et al. NIM A Volume 795, 1 (2015) Phys. Rev. D 101, 072002 (2020)

 7
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New Generation Photodetectors
Large area picosecond photodetector (LAPPD):
Micro-channel plate, fast-timing photodetectors
• Large-area: 20 ⨉ 20 cm
• Fast timing: ~70 ps time resolution
• High quantum e ciency (QE): >20-30 %
• Position resolution: mm scale

Very fast large-area & HQE PMT
TTS~500ps
Q.E. > 30%

Large-area red-sensitive PMTs
TTS~500ps
Q.E. > 30%

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 ffi

Dichroic filters (Wavelength discrimination)

 Mainz

 T. Kaptanoglu et al JINST 14 T05001 (2019)
 T. Kaptanoglu et al. Phys. Rev. D 101, 072002 (2020)

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Performance measurements and MC studies
 Cherenkov/scintillation
 WbLS characterization: separation at small scale using Prediction of
• Scintillation light yield Monte Carlo muons impact in
• Emission time pro le with model
 large-scale
 betas and X-rays construction
 Monte Carlo model validation detectors
• Emission spectra
 Radioactive
 source
 30cm J. Caravaca et al. Eur. Phys. J. C 80, 867 (2020)
 D. Onken et al., Mater. Adv., 1, 71-76 (2020)
 5cm J. Caravaca et al. Eur. Phys. J. C 77, 811 (2017)
 3cm J. Caravaca et al. Phys. Rev. C 95, 055801 (2017)

6.5cm

 Example of impact on the
 CHESS experiment CNO measurement precision:
 at UC Berkeley
 B.Land, Z.Bagdasarian et al arXiv:2007.14999 (accepted to PRD )
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Scaling up

 2021+ 2024+ 20xx

CV
 ANNIE @FermiLab Start of data taking: ~2016
 (WbLS ~2021-2022)
 Location: Booster Neutrino
 Main Goal: Beam @ FermiLab (USA)
 Show feasibility of WbLS in a Water-volume: 26t
 understanding neutrino-nucleus neutrino-beam environment
 interactions, focusing on production WbLS volume: 0.5t
 and multiplicity of nal-state neutrons Interests: neutrino-nucleus
 interactions

Interest to Theia:
- First deployment of LAPPDs (happening now)
- Deployment of 0.5 t WbLS
- C/S separation in a large-scale experiment
- High and low-energy events reconstruction 12
 A.R. Back et al JINST 15 P03011 (2020)
 M.J.Minot et al NIM A 787, 78 (2015)
- Neutron detection
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Advanced Instrumentation Testbed
 Neutrino Experiment One (AIT/NEO)

 Neutrino Experiment One (NEO) the rst
 demonstration of reactor monitoring in the CV
 far- eld
 Start of data taking:
 ~2024
Main Goal: Location: Boulby
 Underground Lab (UK)
non-intrusively detect the ON/OFF power cycle of a WbLS volume: 1kt
single reactor
 Interests:
 Non-proliferation, Solar
Interest to Theia: neutrinos, NLDBD
• Deployment of kt scale WbLS Neut r i n o
• Low energy antineutrinos detection in WbLS c a ti o n
 Appli

 13 M. Askins et al. arXiv:1502.01132
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Theia: advanced optical multipurpose neutrino detector
 Design options

 Broad physics program:
 Cutting edge Theia-25 Studying neutrino
 developments in the
 fundamental properties
 target material and
 and astrophysical
 photodetection
 objects
 Theia-100 Large scale, multipurpose
 detector
 • Baseline: 25ktonne (17kt FV)
 • Ideal: 100 ktonne (70kt FV)

 14
 THEIA: An advanced optical neutrino detector Eur. Phys. J. C 80, 416

Theia: multipurpose neutrino detector
 Design options neutrino mass
 solar neutrinos
 (CNO, 8B) ordering

 neutrino CP-
 geoneutrinos
 violating phase
 Theia-25
diffuse supernova
 neutrinoless
neutrinos (DSNB) Large scale, multipurpose double beta decay
 detector
 Theia-100 • Baseline: 25ktonne (17kt FV)
supernova burst • Ideal: 100 ktonne (70kt FV) nucleon decay
neutrinos Scintillator fraction tunable
 depending on the physics goal
 ->staged approach

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 THEIA: An advanced optical neutrino detector Eur. Phys. J. C 80, 416
 

Theia-25 at long baseline neutrino facility (LBNF)
 Can be located at fourth Deep
 Underground Neutrino Experiment
 (DUNE) cavern (Depth: 4300 m.w.e.)
 (SURF)

Theia Phase I

 PC: DUNE collaboration

• Using Fermilab’s LBNF neutrino beam for • Precision measurement of neutrino
 long-baseline neutrino oscillation CP-violating phase
 measurements

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Phase I
 Theia: oscillation parameters
 Theia can complement DUNE measurements (same location, di erent target,
 systematics) - important cross-check
 2
 2
 1.27Δm32 L 2
 P(νμ → νμ) ≃ 1 − 2sin(2θ23)sin + f(δCP) + (θ13)
 E
 • Comparison of the unoscillated Theia-100 (70kt FV) Theia-100 (70kt FV)
 ux (measured close to the Theia-25 (17kt FV) Theia-25 (17kt FV)
 beam source) and oscillated
 ux at far distance.

 • Combination of 3D scintillator
 tracker with Theia more similar
 to T2K

 • Long baseline (1300km): more
 matter -> more sensitivity to
 mass hierarchy

 • > 5σ for 30% of CP values (524
 kt-MW-year)

 17 M. Askins, Z.Bagdasarian et al Eur. Phys. J. C 80, 416
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Theia: supernova neutrinos
 Supernova (SN) burst neutrinos Diffuse supernova neutrino background
 (DSNB) Diffuse, isotropic flux of ν from
 all SN explosion in the Universe.
 • High statistics low-
 threshold
 • Flavor-resolved
 neutrino spectra
 • Supernova pointing J. Sawatzki, M. Wurm et al Phys. Rev. D 103, 023021

 • At LBNF: the combination of WbLS (THEIA) and
 liquid argon (DUNE) detectors at the same site
 -> high-statistics co-detection of neutrinos and
 • Cherenkov/Scintillation (C/S) ratio gives a
 powerful handle to discriminate atmospheric neutral
 antineutrinos.
 current background signals;
 • Complementarity to JUNO and Hyper-K:
 opposite side of the Earth -> Earth matter • substantial increase in event statistics when added
 e ects to Super-K and JUNO;
 • Pre-supernova neutrinos • 5σ discovery (125 kton-year): ~8 years (Theia-25) or
 ~2 years (Theia-100)
 M. Askins, Z.Bagdasarian et al Eur. Phys. J. C 80, 416
ff

Phase II
Theia: solar neutrinos
 Theia can continue Borexino’s solar
 legacy

 - CNO neutrinos (directionality
 based background rejection,
 solar metallicity puzzle
 M. Askins, Z.Bagdasarian et al Eur. Phys. J. C 80, 416

 -

 Pee
 8B solar neutrinos high-statistics, Vacuum
 Matter enhanced
 oscillations
 flavour conversion
 low-threshold -> new physics in
 the MSW-vacuum transition
 region

 Borexino measurements Nature 562, p 505
 19
 :

 )

Phase II
Theia: Geoneutrinos

 • Rate at Sanford Underground Research
 Facility (SURF): 26.5 interactions per kT-year

 • High statistics (in comparison with existing two
 measurements)

 • Explore geographical variations of the
 geoneutrino ux

 Analysis of antineutrino capabilities of
 Theia is in preparation

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Theia: Neutrinoless Double Beta Decay
 !"##$$%&'$(&) *&+,$-$./&#$"0/0&#+12+0&,3+%-+##"-$(

 Processes within the Standard Model Neutrinos are their own antiparticles
 Lepton number is not conserved

Elements for which normal beta
decay is suppressed:
Germanium, Xenon, Tellurium • violation of total lepton number conservation
 • absolute neutrino masses
 • mass ordering

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Phase III
Theia: Neutrinoless Double Beta Decay
 !"##$$%&'$(&) *&+,$-$./&#$"0/0&#+12+0&,3+%-+##"-$(
 Isotopes in consideration: 136Xe and 130Te
 Goal: Reach T0ν2β1/2 ~ 1028 years
 Fiducialization and tagging techniques (triple coincidence,
 directionality, etc..) greatly reduce backgrounds

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 M. Askins, Z.Bagdasarian et al Eur. Phys. J. C 80, 416
 
 

Theia: staged approach to physics goals
 Primary physics goal Reach Exposure/assumptions

 Using Fermilab’s Long-baseline
 neutrino beam >5 for 30% of CP 524kt-MW-year
 oscillations

 Nucleon decay T>3.8 x 1034 year 800 kt-year

Conclusions
• Progress in the novel target materials and photodetector technologies opened the
 path for the next-generation neutrinos experiments
• Theia will employ the advantages of these developments
 to achieve: low energy threshold, good energy and position
 resolutions, directionality, large exposure
 and to tackle a broad physics agenda: neutrino oscillations,
 solar, supernova neutrinos, and neutrinoless double beta decay

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Thank you for your attention!

QUESTIONS ARE WELCOME
now

or later
@ZaraBagdasarian
zara.bagdasarian@berkeley.edu
https://www.zarabagdasarian.com

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