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
2008/Apr/17 KPS@Deajeon 19
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