Liquid Scintillator R&D for RENO

2007/Oct/18~19 KPS@JEJU 1

Liquid Scintillator R&D for RENO

Lee, Jaison

For RENO Collaboration

2007/Oct/18~19 KPS@JEJU 2

Contents Introduction

RENO Detector

Liquid Scintillator Formulation

Gd Loaded LS

Long Term Stability

Radiopurity

LS Purification and Handling System

Summary

2007/Oct/18~19 KPS@JEJU 3

Aromatic Oil Fluor WLS Gd-compound

PC(Pseudocumene)PXELAB

Mineral oilDodecane

TetradecaneLAB

PPOBPO

Bis-MSBPOPOP

0.1% Gd compounds with CBX or BDK

Introduction

General Compositions of Liquid Scintillator (LS)

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

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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 Acryl Vessel - Systematic error ↓ : Radiopurities ↓

Introduction

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Liquid Scintillator R&D 에서 수행하는 사항들 :

- 구성물질의 조합과 배합 비율 결정

- 빛 방출량 측정

- 투광도 및 흡광도 측정

- purification system

- 주기적 측정에 의한 장기적 안정성 검사

- 변색 여부 검사

- 아크릴의 거부 반응 여부

INR/IPCE 러시아 그룹 (Gd powder 생산 ) 과 공동연구 : 2 회 방문연구 수행

Introduction

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-catcherbuffer

PMT surface

1.4m 1.6m0.6m

veto

0.7m1m

0.177m

Target

RENO Detector• Target : LS + Gd (0.1%)• Gamma Catcher : LS• Buffer : M.O.• Veto : Water

Inner Diame

ter(cm)

Inner Height(cm)

Thickness

(mm)Filled with

Volume

(m3)

Mass(tons

)

Target vessel 280 320 12 Gd(0.1%

) +LS 19.7 15.4

Gamma

catcher

400 440 8 LS 35.2 27.5

Buffer tank 540 580 4 Mineral

oil 76.9 59.2

Veto tank 740 780 15 water 201.8 201.8

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  화학식 H:C

M.W.(g/

mol)Density(g/ml)

Boiling 

PointFlash Point

Viscosity

@20 도 기타decane C10H22   142.29 0.73 174 46 0.92cps 국내생산 (이수화학 )장점

dodecane C12H26 2.17 170.34 0.7493 216.2 71    

tetradecane C14H30   198.3922 0.767 253 99    

PC C9H12 1.33 120.2 0.89(0.87

6) 169 48   인체 , 환경유해성 최고 . 낮은 FP 문제LAB

C6H5(CnH2n+

1)  233-237 0.86 275-307 130 5-10cps

나라 , 회사마다 quality uncertainty. R&D 결과

없음 . 무해성

PXE C16H18 1.12 210.3 0.988 295 145 5.2cSt@40 생산지문제 (일본생산 )

MOCnH2n+2, n=10-

44    ~0.8   ~110 10-

80cSt@40 Np 개수 불확실성

PC20dod80   2   0.78        

PXE20dod80 

  1.96   0.80   >80    

PC20MO80       0.857        

PC40MO60       0.866        

여 러 solvent 에 대 한 일 반 적 성질

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PC 와 Mineral oil/Dodecane 대용으로 사용할 수 있는 LAB(Linear Alkylbenzene) 의 분자 구조식

PC/PXE + Dodecane 의 대용으로 LAB 사용 가능성 연구

• High Light Yield : not likely Mineral oil(MO)• replace MO and even Pseudocume(PC) probably• Good transparency: 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 measurement

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

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

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PPO (g/ ㅣ ) LY (arb unit)±30

1 444.72 618.73 649.44 634.35 630.96 579.47 577.210 542.720 505.1

Purified LAB(100) + varying PPO PPO 3g/l 일 때 , LY saturation LAB100 + PPO3g/l PC 보다 PPO 가 잘 녹지는 않는다

RENO 측정 (LAB100)

1g PPO2g PPO3g PPO4g PPO5g PPO6g PPO7g PPO10g PPO20g PPO

PPO Concentration

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Bis-MSB(mg/l)

PPO(1):bis-MSB ratio

LY(arb unit)±30

0 0 668.710 1/300 714.720 1/150 855.830 1/100 917.540 1/75 904.450 1/6060 1/50 873.9100 1/30200 1/15 845.1

bis-MSB 양 증가에 따른 LY 최적값을 찾을 수 있다 LAB100+PPO3g/l+bis-MSB30mg/l 60mg 이 넘어가면 , solubility 가 나빠짐

Baseline: LAB100PPO3g/l + varying bis-MSB 0mg/l 10mg/l 20mg/l 30mg/l 40mg/l 50mg/l 60mg/l 100mgl 200mg/l

1/1001/15

bis-MSB Concentration

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Gd Loaded LS

+ LS 는 solvent 로 유기 용액을 사용 . Gd 자체는 유기 용액에 loading 이 안됨 .+ GdR3 로 제작해서 사용 .

R = 2MVA (2 Metyl Valeric Acid) Russia Group 에서 제작하기로 함 .

+ 제작 순서가 중요 .1. GdR3 + stabilizer

: 잘 섞일 때 까지 흔들어줌 .2. Solvent 를 전체 제작 분량에 10% 정도 넣어서 다 녹임 : magnetic stirring 필요3. 다 녹아서 투명해진 것이 확인 되면 나머지 Solvent 를 넣는다 .주의 : Solvent 를 먼저 넣으면 Gd Loading 이 안 된다 .

+ 적정을 하여 Gd 의 농도를 정확히 측정할 수 있다 . ( 0.1% )

Russia 에서 제작한 GdR3

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Long Term Stability of GdLS

- Samples for long term stabilityLT 1 : PC100 + 2TOPO + Gd0.1%LT 2 : PC100 + 3HR + Gd0.1%LT 3 : PC100 + 0.1MTBP + Gd0.1%LT 5 : PC20 + dod80 + 2TOPO + Gd0.1%LT 6 : PC20 + dod80 + 3HR + Gd0.1%LT 9 : LAB100 + 2TOPO + Gd0.1%LT10 : LAB100 + 3TOPO + Gd0.1% LT13 : LAB100 + 2TOPO + Gd0.2%LT14 : LAB100 + 3TOPO + Gd0.2%etc…

- This test are on going.

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Radiopurity of LS

Gd-LS 의 Radiopurity Level 은 매우 중요함 Systematic Uncertainty 에 직접적인 영향을 줌 Sensitivity 에 영향을 줌 Raidopurity 조건 : ~ 1 Hz 정도의 single rate

초 미량의 Radiopurity 측정은 매우 어려움 측정 radio-active material 232Th, 238U, 40K 측정 방법 ICP-MS, NAA, HP-Ge, etc,. 측정 분해능 일반적인 측정기기는 분해능이 낮음 측정 장소 국내 및 국외 측정 가능한 모든 곳을 고려

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Radiopurity of LSSample 238U 232Th 40K

Mineral Oil (KBSI) < 5x10-10 < 2x10-9 0.8x10-6

LAB (non-purified) (SNU) ND 0.15LAB (column purified) ND 0.33LAB (vacuum column (VC) purified) ND 0.20LAB (3 times VC purified) ND 0.12LS(LAB+PPO+bis-MSB) column purified ND NDDetection Limit Th, U < 0.1 ppb (10-10g/g)

- >10-12g/g of radioactivity is required for reducing accidental background.- Now we are measuring radioactivity of LS using ICP-MS at Russia and Japan.- If necessary, LS will be purified further by special methods. (e.g. water extraction)

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Schematic Design for LS Purification and Handling System

N2

Detector

PLS

PGdLS

PMO

P pumpmicro filterflow metermass flow metervalve

200L

200L

200L

1~2 L/minW.E.

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진입터널

Wing tunnelLS 공간

Control room

LS Handling System in Tunnel

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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 titration. 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.

2007/Oct/18~19 KPS@JEJU 18

Back Up

2007/Oct/18~19 KPS@JEJU 19

공대정

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

n=10

n=11

n=12 n=13

LAB Component with GC-MS

n 성분비 (%)10 7.1711 27.6312 34.9713 30.23

2007/Oct/18~19 KPS@JEJU 20

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

2007/Oct/18~19 KPS@JEJU 21

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