KPS@Deajeon 12008/Apr/17

Liquid Scintillator R&D for RENO

Lee, Jaison

For RENO Collaboration

KPS@Deajeon 22008/Apr/17

Contents

Introduction

RENO Detector

Liquid Scintillator Formulation

Gd Loaded LS

Radiopurity

LS Purification and Handling System

Summary

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Prerequisites of Liquid Scintillator

Anti-neutrino Target (Gd loaded) - Light Yield ↑ : Good Scintillating Material - Attenuation Length ↑ : Transparency ↑ - Stability ↑ : Compatible with Acryl Vessel - # of free Proton ↑ : H/C ↑ - Systematic error ↓ : Well understanding mono-molecule , Radiopurities ↓ Gamma Catcher - Light Yield ↑ : Good Scintillating Material - Attenuation Length ↑ : Transparency↑ - Stability ↑ : Compatible with Acryl Vessel - Systematic error ↓ : Radiopurities ↓

Introduction

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Introduction

Aromatic Oil Fluor WLS Gadolinium

PC(Pseudocumene)

PXE

LAB

Mineral oil

Dodecane

Tetradecane

LAB

PPO

BPO

bis-MSB

POPOP0.1% Gd with ligand

General Compositions of Liquid Scintillator

Other Experiments KamLAND : PC(20%)+Dodecane(80%)+PPO Palo Verde : PC(40%)+M.O.(60%)+PPO+bis-MSB+Gd

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Introduction

Liquid Scintillator R&D

- Determination and optimization of quantity of ingredients (fluor, wavelength shifter)

- Measurement of light yield

- Measurement of optical properties (attenuation length, transmittance, etc)

- Gd loading to liquid scintillator

- Long-term stability

- Liquid handling and purification system

Co-work with INR/IPCE of Russia

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RENO Detector

TargetGamma Catcher

InnerDiameter

(cm)280 400

InnerHeight(cm)

320 440

Volume(m3)

19.7 35.2

Mass(tons)

15.4 27.5

Type GdLS LS

×2 (Near and Far)

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Liquid ScintillatorBase Solvent (LAB)

- High Light Yield : not likely Mineral oil(MO)- Replace MO and even Pseudocume(PC) probably- Good transparency : ~20m, better than PC- High Flash point : 147oC (PC : 48oC)- Environmentally friendly (PC : toxic)- Components well known, Mineral Oil : not well known- Domestically available: Isu Chemical Ltd.

Light Yield

PC100% LAB100% PC40% PC20% LAB100% PC20% N2 LAB60% LAB80% MO80%

CnH2n+1-C6H5 (n=10~14)

+ PPO (Fluor)

+ bis-MSB (WLS)

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Liquid Scintillator

Optimized PPO Concentration

3 g/L

Bis-MSB concentration [mg/l]

Optimized bis-MSB Concentration

30 mg/L

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Gd Loaded LS

Gadolinium(metal) cannot be dissolved in the organic solvent!!→ Make Gd-salt using ligand

Ligands

β-diketonesLow solubility and short a

tt. length

Organophosphorous Short att. length

Carboxylic acids

MVA Precipitation

EHA Low solubility

TMHA Most promised

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Gd Loaded LSprecipitation

Rinse with 10MΩ water several times

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Radiopurity Radioimpurities (40K, 232Th and 238U) in the LS can make the accidental background with neutrons coming from cosmic muons.

Single event rate by radioimpurites is calculated by full detector simulation based on GEANT4, and with 10-12 g/g of concentration of each isotope it will be ~3 Hz.

Th U

> 1.1×10-11 > 8×10-12

Concentration of LAB (ICP-MS)

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LS Handling and Purification System

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LS Handling and Purification System

진입터널

Wing tunnel

LS 공간

Control room

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Summary

We are doing LS R&D for RENO.

The composition of LS has been optimized.

Gd is successfully loaded to LS, and its concentration can be measured by ti

tration.

GdR3 will be produced at large scale for Mockup and full detector.

We decided the LS formulation for Mockup detector.

We continue to test the long tem stability of LS.

We are designing the LS purification and handling system.

We are going to adapt the results of R&D to Mockup.

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Back Up

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CnH2n+1-C6H5 (n=10~14)

LAB Component with GC-MS

n 성분비 (%)

10 7.17

11 27.63

12 34.97

13 30.23

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Light Yield of Liquid Scintillator

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LAB has lower optical absorption, better attenuation length

100% LAB and PC have similar light outputs

We got similar results with BNL & Daya Bay experiment

100%82%96%

Absorption spectra Light output spectra

Performance of Gd in PC & LAB

w/o Gd

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Gd 적정 방법

+ 필요한 물품 : 비커 , 증류수 , GdLS, indicator, buffer solution, EDTA, 적정용 뷰렛

Indicator (Xylenol Orange): 보라색 -> 노란색으로 변함 Buffer solution: 수소이온 농도를 일정하게 유지하려고 하는 용액EDTA (EthyleneDiamineTetraAcetic acid): Gd 와 높은 반응성

1. 비커에 증류수를 20ml 가량 넣는다 .2. GdLS 를 2ml 넣는다 .3. Buffer solution 2ml + indicator 4 drop : 비커에 담긴 용액이 엷은 보라색을 띈다 .4. 용액의 색이 노란색으로 변할 때까지 EDTA 추가

VEDTA * CEDTA = VGdLS * CGdLS

적정 전의 색 끝났을 때의 색

지시약

EDTA

Buffer solution

적정용 뷰렛