(Metal-doped and Water-based) Scintillator Technology

Minfang YehNeutrino and Nuclear Chemistry

FroST, FNAL, 03/18-20/2016

Overview Scintillator Physics

Water-based Liquid Scintillator

Metal-doped Liquid Scintillator

Ongoing and future scintillator R&D’s

Summary

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Mea

n A

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Cerenkov (e.g. Super-K, SNO)

water-like WbLS• Cerenkov./Scint.

detection

Oil-like WbLS• Metal-loaded LS

Water-based Liquid Scintillator

Scintillator (e.g. SNO+, Daya Bay)

Scintillator ApplicationsProton decay 0νββ Solar neutrinos (w 7Li loading)Geo-neutrinosSupernova neutrinosDiffuse SN background neutrinos long baseline neutrino physics (w accelerator neutrino source)Sterile neutrinos (w neutrino source)Ion-beam therapy imagingTOF-PETSome details in arXiv:1409.5864

Cherenkov vs Scintillation

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KamLAND

Daya Bay

SNO+

NoVA Borexino

Scintillator is an excellent detection medium for neutrinos in MeV range Tune scintillator cocktails to meet the needs of various physics

Main Neutrino Interactions in Scintillator

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zsolvent WLS

fast and slow components

Scintillation Mechanism

• Scintillator Stokes shift, timing structure, and C/H density determine the detector responses

wiki

Stokes shift

fast

slow

Ranucci et al.

Birk’s

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Scintillator ComponentsC. Buck and M. Yeh, Submitted to J. Phys. G (2016)

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Liquid Scintillators

1-phenyl-1-xylyl-ethane (PXE)1,2,4-trimethylbenzene (PC)

Di-isopropylnaphthalene (DIN)

Cyclohexylbenzene (PCH)

Linear alkylbenzene (LAB)

C. Buck and M. Yeh, Submitted to J. Phys. G (2016)

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Primary and Secondary Wave-Length-Shifter

C. Buck and M. Yeh, Submitted to J. Phys. G (2016)

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Examples of (some) Scintillator Cocktails

C. Buck and M. Yeh, Submitted to J. Phys. G (2016)

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Daya Bay (0.1 wt.%) Gd-LS produced in Oct. 2010 (monitored at BNL)

Oct 2015

Pulse Shape Discrimination

DayaBay

JSNS2

n

n

• PSD to distinguish different particle interactions; i.e. proton recoils from electron-like events

• Select IBD events from cosmogenic fast neutrons and ambient-related gammas; particularly important for near-surface detectors

• LAB-based scintillator doesn’t have good n- separation; DIN or other “pseudo” toluene scintillators pose better PSD

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Cherenkov/Scintillation Separation

electrons

neutrons

LSND rejects neutrons by a factor of 100 at ¼ Cherenkov & ¾ Scintillation light (NIM A388, 149, 1997).

Cherenkov is <5% of scintillation

Separation of Cherenkov from scintillation allows directional cut for particle ID

• Fast photosensors/electronics (LAPPD)• Ratio of scintillation light in Cherenkov• Slow scintillation decay time• Adequate scintillation yield

Prompt Cherenkov peak

Long scintillation tail

Z. Wang’s talk

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A 50-m WbLS SK-like detector (100ph/MeV)• Tk+= 90MeV • 20% coverage with 25% QE photocathode• Deep underground >3000 m.w.e.• Fast decay at 12ns

Water-based Liquid Scintillator

• A novel scintillation liquid ranging from ~pure water to ~pure organic

• Motivated by physics below EChev and scintillation separation in WCD

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• Adjustable scintillation light yield from 1 to 15% LS added to waterfor physics of interest

• Long attenuation length (LS~20m, water ~100m, (1%)WbLS~30m)

• Particle identification/reconstruction:

• Directional (Cerenkov) and isotropic (Scintillation) light

• Timing of prompt Cerenkov and scintillation light

• Energy measurement via calorimetry (scint.) and Cerenkov threshold

• Low-cost: (1%) WbLS using LAB (linear alkylbenzene) derivatives as LS ~ $(30+H2O)/ton

• Environmentally and chemically friendly

• Enables dissolution of lipophobic but hydrophilic metals

Cherenkov• <400nm overlaps with scintillator

energy-transfers will be converted to scintillation isotropic light.

• emits at >400nm will propagate unabsorbed (directionality).

WbLS Principals

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WbLS Properties

1%WbLS ~109 op/MeV

L.J. Bignell et al 2015 JINST 10 P12009

NSRL

L. Bignell’s talk

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Reactor

Solar

Others

Metal-doped LSfor Neutrino Physics and Other Applications

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Early Development of M-doped LS

• LENS plays a key roleIndium loaded scintillator for low energy solar neutrino spectroscopy, L. N. Pfeiffer, A. P. Mills, R. S. Raghavan and E. Chandross, Phys. Rev. Lett. 41, 63 (1978).

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C. Buck and M. Yeh, Submitted to J. Phys. G (2016)

Metal-loading Techniques Organometallic complexes (multi-step)

• Require a complexing ligand• Solvent extraction or solid dissolution• Not effective for hydrophilic elements

Direct mixing (one-step)• Quantum dots• Water-based LS mixing• Scattering dominates the optical

transparency

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Organometallic Complex Carboxylic acid

• Metal-carboxylates either dissolved or extracted in scintillator (up to 10 wt.% tested)

• From C2 to C9 as early development by LENS (In-LS and Yb-LS)• C6 for Gd-doped PC; C9 for Gd-doped LAB• Palo Verde, Daya Bay, RENO

-diketone (BDK)• Metal--ketoester complex soluble in scintillator (~10 wt.% tested)• Early development also in the context of LENS• 2,4-pentanedione (Hacac) and 2,2,6,6-Tetramethylheptane-3,5-

dione (Hthd)• Double-Chooz, Nucifer

A new approach using Te-diol complex is under development by SNO+ (very promising)

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Quantum Dots Method of metal-doped LS by suspension Property depends the size of dots (nanometer) Absorption and reemission can be tuned for a

respective application (allowing Chev/Scin separation) Most dot cores are binary alloy, i.e. CdSe, CdTe, ZnS Scattering domination and stability concern in

aggregation

T. Wongjirad’s talk

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Lead-doped scintillator calorimeter • Solar neutrino• Total-absorption radiation detector

(Medical)

Tellurium-doped scintillator detector • Double-beta decay isotope (130Te, 34%

abundance)• Future ton-scale 0ββ

Lithium-doped scintillator detector • Solar neutrino (7Li, 92.5% abundance)• Reactor antineutrino (6Li, 7.6% abundance)

A metal loading technology using water-base Liquid Scintillator principal• feasible for ~most metallic ions

(particularly hydrophilic elements)

• less-selective isotope loadingRequire extensive purification for radiopurity

WbLS Loadings

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DayaBay/RENO/DC (0.1 wt.%), LZ (0.1 wt.%), medical imaging (10 wt.%), etc.

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0.3% Te Diol in LS3% Te Diol in LS3%Te Pseudo-PRS in LS6%Te Pseudo-PRS in LS0.3%Te Pseudo-PRS in LS

Channels

A/U

• A beautiful organotelluric diol complex that is very soluble in scintillator (e.g. Te~17 wt.% in LAB)

• Optical transparency doesn’t change with increasing loading

• Diol is a quencher, which needs mitigation at higher loading; but Te 0.5 wt.% is ok

• Te-diol-WbLS for >10 wt.%?

-0.010.010.030.050.070.09

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Abs

Wavelength (nm)

0.3% Te in LS_ops 2_03-08-16

3% Te in LS_ops 2_03-08-16Te-diol

Metal Effect

• G. Consolati, D. Franco, S. Hans, C. Jollet, A. Meregaglia, S. Perasso, A. Tonazzo, and M. Yeh, PRC 88, 065502 (2013)

• S. Perasso,a,1 G. Consolati,b D. Franco,a C. Jollet,c A. Meregaglia,c A. Tonazzoa and M. Yeh, JINST, v9, March 2014

Doped metal affects the o-Ps fraction; but not its lifetime

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T2K ND-280

WbLS Near

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1. WbLS-based “phantom” would serve as a real-time quality assurance device• Intensity-modulated pencil proton beam therapy

(IMPT) in which a tumor can be targeted for radiation while sparing the surrounding healthy tissue

• Requirements• Ability to withstand ~600Gy yearly facility dose• Understanding of light yield and collection to ~1-2%

• Industry Collaborator: Phenix Medical LLC • SBIR submitted

• Patent Incentive submittedd in 2015

2. 3-D Imaging TOF-PET• Radiation calorimetry • 10% Gd- or Pb-doped WbLS• University collaborator: U. Chicago• PCT Patent submission in 2016 F. Reines

Medical Applications

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1. LY reduced 1.74±0.55% and 1.31±0.59% for LS and 5%WbLS respectively after ~800Gy dose at NSRL

2. Implies ~0.1%LY reduction in one year of operation of a proton therapy QA device

Radiation hardness

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WATCHMAN-II (DNN)

“the U.S. to host a large water Cherenkov neutrino detector, as one of three additional high-priority activities, to complement the DUNE liquid argon detector…This approach would be an excellent example of global cooperation and planning” – P5 (Scenario C)

A large water Cherenkov detector (future)

THEIA

60m

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Scintillator R&D (future)

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Sharpen (XL) Purification Techniques Nitrogen purging

• Radon removal• Oxygen quenching

Distillation• Radioisotope removal• Colored impurities

Water extraction• radioisotope removal (e.g.

K in PPO) Sublimation

• M-BDK, PPO, etc.

Column purification• Colored organic removal• Metal removal

Nanofiltration• U/Th removal from metal-

feedstock (e.g. Gd-H2O)• WbLS?

Recrystallization• PPO, metal-feedstock (e.g.

TeOH6)

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Major techniques developed by Borexino, KamLAND, SNO+, JUNO, etc; (F. Calaprice talk)

UC Davis at BNL

UM/CSU/UF/KEK at BNL

• LBNL/UC Berkeley/UC Chicago: Developing facility for WbLS timing and light yield in a cosmic-muon imaging experiment using fast PMTs

• UC Irvine/LLNL: 100-L production for long-arm attenuation measurement

• UC Davis: 10L production for in situ (nanofiltration) circulation study: purification by differentiating molecular sizes (with BNL)

• CSU/TRIUMF: T2K-ND High light yield WbLS with 70% water target

• LBNL/UCB/UCD/LLNL: RAT-PAC software framework for simulation (GEANT4) & reconstruction

• Yale/NIST/LLNL: Li-doped LS• UM/CSU/BCC: PSD-enhanced Gd-doped LS• Temple U: calibration source Ac-doped LS• BNL: 1-ton scintillator prototype

Ongoing (Wb)LS R&D

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1000 liter WbLS demonstrator A right cylindrical vessel to

measure WbLS properties regarding to optical/light-yield. Cherenkov and scintillation separation, etc.

Test purification and circulation (if needed)

Installed vessel before completion of dark box

1000-liter WbLS prototype in dark box

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Filled with water from reverse osmosis purification system in Dec 2015

Simulated cosmic muon in water. Red points are absorbed & reflected photons

No black barrier

With black barrier

Addition of black Teflon optical barrier to minimize reflections

1000 liter WbLS demonstrator

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Ton-scale Scintillator Production Facility

A ton-scale-per-batch production capability at BNL (CY16) Mission of 22-ton radiopure 0.1%Gd-LS (veto) for LZ (FY17/18) Available for other scintillator production in FY19

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• Liquid scintillator continues to be a key detection medium in neutrino physics

• Metal-doped LS technique expands physics reaches and is rather mature with continuing improvement

• WbLS at ton-scale• 1%WbLS is well-understood in terms of

property and cost• Circulation technique is next step• A ton-scale scintillator production and

prototype facility• Increasing community R&D:

• US/JP for ANNIE/NuPRISM• NSF for JSNS2 for metal-doped LS• DNN for WATCHMAN• SBIR/TM for medical application

ONP-supported

Summary

A variety of scintillator applications in physics, nonproliferation, and medical imaging

03/19/2016

Supported by DOE-HEP-KA25/DOE-ONP-LE/LDRD

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