Water-based Liquid Scintillator and Isotope Loadings Minfang Yeh - - PowerPoint PPT Presentation

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Water-based Liquid Scintillator and Isotope Loadings Minfang Yeh - - PowerPoint PPT Presentation

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Water-based Liquid Scintillator and Isotope Loadings Minfang Yeh Neutrino and Nuclear Chemistry, Brookhaven National Laboratory Future Solar Neutrino Detector at JinPing Water-based Liquid Scintillator 12000 Optical Photons per MeV LAB in

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SLIDE 1

Water-based Liquid Scintillator and Isotope Loadings

Minfang Yeh

Neutrino and Nuclear Chemistry, Brookhaven National Laboratory

Future Solar Neutrino Detector at JinPing

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SLIDE 2

2000 4000 6000 8000 10000 12000 50 100

Optical Photons per MeV LS%

Water-based Liquid Scintillator

  • A cost-effective, new liquid medium

utilizing nonlinear light-yield as a function

  • f scintillator % and superior optical

property of water for physics below Cerenkov or low-energy neutrino detection

  • Cherenkov transition
  •  overlaps with scintillator energy-transfers will

be absorbed and re-emitted to give isotropic light.

  •  emits at >400nm will propagate through the

detector (directionality).

  • PID using timing cut and energy

reconstruction to separate the directional Cherenkov (fast) and isotropic scintillation (slow, controllable)

  • Environmentally and chemically friendly

electrons neutrons LSND rejects neutrons by a factor of 100 at ¼ Cherenkov & ¾ Scintillation light (NIM A388, 149, 1997). 20%LS give ~50% light as a pure LS Minfang Yeh, BNL 6/17/2014 2 LAB in cyclohexane

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SLIDE 3

Cherenkov & Scintillation Separation

  • Cherenkov is ~5% of

scintillation in conventional scintillators

  • Difficult to reconstruct

directionality

  • At 1%WbLS, Cherenkov:

scintillation is ~1:1

  • Slow scintillator vs. prompt

Cherenkov

  • Cherenkov and Scintillation

separation could discriminate low-energy , e-, e+ and 

  • More  background

suppression, larger detector fiducial volume

Minfang Yeh, BNL 6/17/2014 3

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SLIDE 4

4

20 40 60 80 100 120 140 160 180 100 1000 10000 Mean Absorption Length (m) Photon/MeV

Two types of WbLS

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

Oil-like

  • A new loading

technology for hydrophilic elements

Minfang Yeh, BNL 6/17/2014

Water-based Liquid Scintillator

Water-like

  • >70%H2O
  • Cherenkov +

Scintillation

  • Cost-effective
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SLIDE 5

Liquid Scintillator Development Facility

  • A unique facility (since 2002) for Radiochemical, Cerenkov, and Scintillator

(water‐based and metal‐doped) detectors for particle physics experiments.

  • Expertise trained and facility established over years of operations.
  • $1M facility including XRF, LC‐MS, GC‐MS, TFVD, FTIR, UV, Fluorescence

emission, light‐yield coinc. PMT, 2‐m system, low bkg. counting, etc. (access to ICP‐MS at SBU) for detector R&Ds and prototype tests.

Minfang Yeh, BNL 6/17/2014 5

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SLIDE 6

WbLS Cherenkov & Scintillation Detection

K+ μ+ e+ μ+ e+

Hit Time (Time of Flight Corrected) [ns] Number of PE

10 102 103 104 50 10 15

p → K+ + ν e+ + νμ + νe _ μ+ + νμ 12 ns 2.2 μs

  • Proton decay remains to be one of the top challenges
  • A simulated event with 90 scintillation photons/MeV in a SK detector for p → kv
  • An order of magnitude improvement over the current SK sensitivity (2.31033 yrs)

Minfang Yeh, BNL 6 6/17/2014

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SLIDE 7

Good Attenuation Length Fast Timing

  • Started R&D since 2009
  • A clean liquid (at 450nm and above);

need 104 optical purification

  • A fast pulse
  • can load as much as 35% of LS in

H2O

  • Investigate light propagation

below and above Cerenkov

  • proton beams & sources

1% WbLS-2012 (Proof-of-Concept)

Minfang Yeh, BNL 6/17/2014 7

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SLIDE 8

WbLS Detectors

NSRL @BNL

210 MeV dE/dx ~ K+ from PDK 475 MeV Cerenkov threshold 2 GeV MIP

3 low Intensity Proton Beams

Water pure water WbLS 1 0.4% LS WbLS 2 0.99% LS LS pure LS

4 Material Samples

Tub 1 PTFE (highly reflective white Teflon) Tub 2 Aluminum coated with black Teflon

2 Detectors

Proton-beam Measurements at BNL

Minfang Yeh, BNL 6/17/2014

  • Two NSRL runs from 2012-2013
  • Same sample; different geometries
  • Cherenkov at higher energy and scintillation

below Č threshold

8

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SLIDE 9
  • Cherenkov dominates at 2GeV while scintillation takes over at

475MeV and below

  • Principals of detection below Cherenkov threshold are proven

*

1 2 3 4 5 6 7 8 9 10 100 1000 10000 Charge (PE/MeV) Beam Energy (MeV)

T1 (white Teflon) Charge (in PE/MeV)

Water Sample WbLS1 Sample WbLS2 Sample LS Sample /30

Scintillation below Cherenkov threshold

0.001 0.01 0.1 1 10 0.1 1 10 100 Sample/LS Ratio LS Concentration (%)

Ratio to LS at 475-MeV

T1 Data T2 Data

linear or nonlinear?

Minfang Yeh, BNL 6/17/2014 9 LS response is divided by 30

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SLIDE 10

Reactor  Solar Others

WbLS Isotope loading

Metal-loaded LS for Neutrino Physics

Minfang Yeh, BNL 6/17/2014 10

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SLIDE 11

Examples of Metal-doped WbLS

Minfang Yeh, BNL 6/17/2014

Lead-doped scintillator calorimeter

  • Solar neutrino
  • Total-absorption radiation detector

Lithium-doped scintillator detector

  • Solar neutrino (7Li, 92.5% abundance)
  • Reactor antineutrino (6Li, 7.6% abundance)

11 Conventional loading is no good for hydrophilic ions (i.e. Te)

  • Conventional loading method using organic

complexing ligands has been successfully applied to reactor ̅ detection (e.g. Gd-LS)

  • –OH group is a known quencher
  • difficult for hydrophilic elements
  • WbLS adds a new dimension of metal-loading

8-MeV ’s (Gd) vs. ,T (6Li) Neutron Tagging

Tellurium-doped scintillator detector

  • Double-beta decay isotope (130Te, 34% abundance)
  • Future ton-scale 0ββ
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SLIDE 12

Solar Neutrino Targets

Minfang Yeh, BNL 6/17/2014 12

7Li + e7Be + e-

  • group state (Ethresh = 0.861 MeV) and first excited state (Ethresh = 1.339 MeV)
  • High abundance at 92.5%
  • Conventional organometallic loading is not stable (e.g. Bugey-3)
  • 1~3% loading using WbLS (aligned with short-baseline reactor experiments)

115In + e  115Sn + e- + (τ =4.76 µs) 2 γ (LENS)

  • High nature abundance at 95.7%
  • Low Q value at 114-keV, sensitive to >95% pp continuum
  • Triple coincidence allows tagging of e event
  • 6-8% loading with conventional organometallic technology

208Pb + e  208Bi* + e- & 208Pb + x  208Pb* + x (HALO)

  • Abundance at 52.4%
  • Bursts of neutrons via CC and NC
  • Neutron detection by IBD reaction using scintillator (208Pb is a double magic nuclei)
  • Targeting 10% natPb using WbLS (aligned with medical applications)

Few others: 11B, 35Cl, 31P,…, etc.

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SLIDE 13

13

Li-loading by WbLS

Minfang Yeh, BNL

Daya Bay PROSPECT

BNL + Yale PSD enhancement for 0.1% Gd-doped LS (compatible with plastics) over 6 months; and further improvement can be achieved 6/17/2014

A stable 0.1% Li-LS at ~5000 ph/MeV

  • A Li-doped (0.1-0.5%) LS that has been stable
  • ver 1.5 years (light-yield and optical better

than commercial product) for PROSPECT

  • Background investigations at three different reactor

sites

  • Start full-scale (~10 tons) at Near Site in 2015
  • Improve PSD as demonstrated by Gd-LS;

applicable to Li-LS

  • Continue R&D for higher loading at >1%

0.01 0.02 0.03 0.04 0.05 200 700 Absorbance Wavelength (nm)

51213 71913 90813 103113

500 1000 1500 2000 2500 3000 3500 4000 1000 Counts (AU) ADC Channel

0.1% Li - 2nd formulation 0.1% Li Commercial Product LAB + PPO + MSB

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SLIDE 14

How practical is a large water Cherenkov scintillation detector?

Minfang Yeh, BNL 6/17/2014 14

  • “the U.S. to host a large water Cherenkov neutrino detector, as one of three

additional high-priority activities, to complement the LBNF liquid argon detector, unifying the global long-baseline neutrino community to take full advantage of the world’s highest intensity neutrino beam. The placement of the water and liquid argon detectors would be optimized for complementarity. This approach would be an excellent example of global cooperation and planning” – P5 (scenario C)

  • First WbLS-LBNF workshop was held at LBNL in June:

http://underground.physics. berkeley.edu/WbLS/slides/

  • A group study to explore potential physics by WbLS
  • BNL, LBNL/U. Berkeley, U. Penn., UC Davis, U. Chicago, U. Princeton,

UCLA, U. Hawaii

  • A technical or white paper is under discussion
  • Regular phone calls and R&D proposals are planned
  • International workshop?
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SLIDE 15

0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.1 200 300 400 500 600 Absorption Length (1/m) Wavelength (nm)

WbLS-2014 (extinction coefficient) WbLS-2012 SK-water

1% WbLS-2014

Minfang Yeh, BNL 6/17/2014

  • Water-like WbLS (e.g. WATCHMAN)
  • The WbLS-2012 needs 104 optical

purification

  • relying on the vendor for a cleaner starting

material

  • Multi-step technologies proven; but high

cost and labor-consuming

  • The WbLS-2014
  • New chemical components
  • Non-purified and includes scattering; need

to measure its effect

  • extinction coefficients calculated from each

component (successfully predict LS)

  • total = organic + water
  • organic ~ water ~ 0.0046 (m-1) at 430nm
  • Region of 300-400nm dominated by

flour/shifter; need to be optimized

  • ptical improvement after one-pass

15

WbLS non-purified

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SLIDE 16

1% WbLS-2014 cont’d

Minfang Yeh, BNL 6/17/2014

  • WbLS light-yield as a function of LS%

loading

  • Higher light-yield at the cost of optical

transmission

  • Linear correlation between light-yield

and LS% (up to ~15%)

  • Behave differently compared with pure

scintillator

  • WbLS-2014 has ~25% more light-yield

than WbLS-2012

16

1 10 100 1000 0.1 1 10 100

Compton Edge, AU

LS % in Water

WbLS 2014 WbLS 2012

1 10 100 1000 10000 1 10 100 1000 Counts (AU) ADC Channels

WbLS 1% WbLS 4.7% WbLS 8.14% WbLS 10.1% WbLS 13.9% LS H2O WbLS 1% (NSRL 2012)

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SLIDE 17

Material Cost

  • WbLS (at 1 kiloton or bigger)
  • Organic Solvents ($100 for every %LS in a ton)
  • H2O (excluded)
  • Fluor/Shifter: (PPO at 2g/L for pure LS

detector~$600/ton)

  • 1% WbLS needs only 0.02g/L for $6/ton?
  • Other shifters?
  • Optimization is needed
  • A water-like 1% WbLS costs $(0.1k + $fluor)

per ton

  • An oil-like WbLS (e.g. SNO+ or PROSPECT),

cost is dominated by price of oil

Minfang Yeh, BNL 6/17/2014 17

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SLIDE 18

Compatibility in Liquid

Minfang Yeh, BNL 6/17/2014 18

0.01 0.02 0.03 0.04 0.05 200 400 600 800 Abs Wavelength (nm)

3/7/2014 3/13/2014 3/24/2014 3/31/2014

  • BNL has a compatibility program serving to several experiments
  • High s/V ratio (or elevated temp) to speed up the test
  • Impact of material on liquid
  • Acrylic, PP, and PFA are good in 10% WbLS
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SLIDE 19

Compatibility of Materials

Minfang Yeh, BNL 6/17/2014 19

Atomic force microscopy (AFM) high-resolution scanning (acrylic in EtOH) 0.5 1 1.5 750 1750 2750 3750 AU Wavelength (nm)

1 5 4 2

FT-IR Microscope (acrylic in EtOH)

  • Impacts of liquid to material
  • Start to inspect materials by AFM and high-intensity FT-IR at

BNL-NSLS

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SLIDE 20

Circulation of WbLS

Minfang Yeh, BNL 6/17/2014

extensive studies by environmental researches in academia and industry

  • Biodegradable?
  • Surfactant degradation (e.g. LAS) only
  • ccurs at <50mg/L.
  • Surfactant at 100mg/L or higher completely

inhibits bacteria growth

  • 1% WbLS is 105 mg/L
  • Stable in acrylic and glass containers

for 2+ years for WbLS-2012 and 6 months for WbLS-2014

  • Water-like WbLS might not need

circulation if careful selection of vessel and material-in-contact

  • Passing 0.1 micron filter is ok
  • Oil-like WbLS doesn’t require

circulation (e.g. SNO+, PROSPECT)

20

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SLIDE 21

SNO+ (0ββ) T2K (Near detctor) PROSPECT (US‐SBL) Others? (solar, calibration,…)

Common features between detectors unique requirement for individual detector

Liquid Scintillator

(Metal‐loaded & Water‐based) WATCHMAN (nonproliferation, p‐decay, etc.) Ion‐beam therapy & TOF‐PET scan

Current WbLS Applications…

Minfang Yeh, BNL 6/17/2014 21

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SLIDE 22

Experimental Requirements

Experiment Detector Components

SNO+

WbLS (90%+) doped with 3%Te (130) 0ββ isotope

PROSPECT

WbLS (70%+) doped with 0.1% Gd or 6Li with high PSD

WATCHMAN

WbLS (1%) doped with 0.1%Gd

T2K

WbLS (10%)

Medical Applications

WbLS (1-5%) for QA phantom or doped with high Z element (~10%) for TOF-PET

Minfang Yeh, BNL 6/17/2014 22

  • Oil-like WbLS (>70% LS): SNO+, PROSPECT
  • Water-like WbLS (>70% H2O): T2K, medical imaging, WATCHMAN
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SLIDE 23

Summary

  • Principals of WbLS detection and isotope loading have been proven;

the current developments focus on ongoing and newly proposed experiments (every detector has different requirements); 1-ton prototype is under construction

  • JinPing is the deepest underground facility at 7500 mwe, ultralow

cosmogenic background for solar neutrino and other rare-event Physics

  • A WbLS detector with 7Li, 115In or 208Pb loading? the size of cavern is

limited for water or scintillator detectors

Minfang Yeh, BNL 6/17/2014 23