1. RENO Liquid Scintillator R&D Daejung Kong (KNU) KPS Spring Meeting, April 19, 07 경북대, 경상대, 동신대, 부산대, 세종대, 서울대, 서울시립대, 성균관대, 전남대, INR/IPCE ( 러시아 ) Introduction Gd-LS R&D Purification Summary and plan

2. Target - LSc + Gd Gamma catcher - LSc Buffer - Non Scinti. Veto - Water Shielding p ν e e + e - γ (0.511MeV) n Gd γ γ γ γ E g å ~ 8MeV 30μs prompt signal Delayed signal Core component Liquid Scintialltor for RENO Gadolinium Large neutron X-section, BKG rejection (coincidence) Liquid Scintillator High light output, good optical properties, Long term stability, H/C, Radiopurity

3. 2007 KPS spring Meeting3 Gd+Liquid Scintillator R&D  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  Liquid Scintillator 의 일반적 구성 물질 : AromaticOilFluorWLSGd-compound PC(Pseudocumene), PXE, LAB Mineral oil, Dodecane, Tetradecane, LAB PPO, BPO Bis-MSB, POPOP 0.1% Gd compounds with CBX or BDK

4. 2007 KPS spring Meeting4 ChoozPalo Verde GdGd(NO 3 ) 3 Gd 2 O 3 Loading Methods Dissolved in hexanol + LSConverted to carboxylate + LS Light degradation 0.4 % / day0.03 % / day RemarksUnstable  Turned YellowStable  still usable Lesson and R&D about Gd-LS Gd loading is a key issue Gd loading is not trivial Experienced Russian Group (INR) joined  6 months stable Gd-LS R&D with INR

5. 2007 KPS spring Meeting5 Gd compound structure R1R1 3+ Gd R2R2 O O O O O O HC - C-C- H C-C- H R1R1 R1R1 R2R2 R2R2 Gd 3+ R O O O O O O C C C R R CC O - H + O R H H R C CH 2 R 2 C OO GdCBX GdBDK  -diketonates: Carboxylic acids:

6. 2007 KPS spring Meeting6 Liquid Scintillator R&D 현황 R&D Safety 와 환경문제 Domestic Availability Remarks LAB100 RENO/Daya bay Much less toxic YESInexpensive, 환경 친화적 PC20Dod80 Daya Bay/RENOtoxicNOExpensive PXE20Dod80 Double ChoozLess toxicNOUnstable  claimed by Daya bay PC20MO80 PC40MO60 Palo Verde Chooz toxicAvailableComponents?, purification

7. 2007 KPS spring Meeting7 Optimization of Fluor and WLS Optical properties (absorption,..) Measurement of Gd concentration purification (transparency, radio-purity) Measurement of LS components Light output - Nitrogen flushing effect RENO Gd (un)loaded LS R&D 현황

8. 2007 KPS spring Meeting8 Solvent : LAB 1g PPO 2g PPO 3g PPO 4g PPO 5g PPO 6g PPO 7g PPO 10g PPO 20g PPO Optimization of PPO, bis-MSB Concentration  Purified LAB(100) + varying PPO  PPO 3g/l 일 때, LY saturation 0mg/l 10mg/l 20mg/l 30mg/l 40mg/l 50mg/l 60mg/l 100mgl 200mg/l  LAB100+PPO3g/l+bis-MSB30mg/l

9. 2007 KPS spring Meeting9  Beer-(Lamvert-Bouguer) law  = 0.4343 (L/(A 420 -A min )) L: cell path length A: absorption at 420nm 정제 전 정제 후 정제방법 (Al 2 O 3 adsorption) LAB( 이수화학 ) 흡광도 [Abs] 조사

10. 2007 KPS spring Meeting10  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 Gd loaded Gd unloaded

11. 2007 KPS spring Meeting11 Sample Composition (ligand) [Gd](%) Remarks 첨가물 1 *3HR0.109HR(0.92m) 2 *3TBP0.108TBP(0.5m) 3 *2TOPO0.118TOPO(99%) 4 *3TOPO0.110TOPO(99%) 측정 결과 indicator buffer solution EDTA ① PH> 5 에서 Gd 은 EDTA 와 반응도 높다 ② EDTA 는 indicator 와 반응해, 보라색에서 노란색으로 색깔 변화 ③ V EDTA * C EDTA = V sample * C sample Indicator GdLS Buffer solution (PH>5) Gd buffer solution (PH>5) Gd 농도 측정 방법

12. 2007 KPS spring Meeting12 적정횟수 Gd Concentration (%) 10.096 2 30.094 측정 Attenuation length (m) 15.65 26.18 36.19 Note  LS 관련 약품을 살 때는 모두 고순도를 구입해서 사용해야 ( 특히, PPO, ligand)  If not, additional purification will be needed Abs 최종 샘플 흡광도 [Abs], att, 농도 조사

13. 2007 KPS spring Meeting13 정제 전 (m) 정제 후 (m) PXE1.01.3 Dodecane15.216.2 PC5.98.2 MO9.7N/A LAB (batch1)9.515.2 LAB (batch2)7.714.7 Attenuation Length of different solvents before/after purification

14. 2007 KPS spring Meeting14 Transmittance of two different batch samples of LAB B1B2 정제 전후 차이 없음 정제 후가 better 정제 전 B1 > B2 투광도 : batch 에 따라 다소 차이 정제 후 B1 = B2 투광도 batch 에 무관

15. 2007 KPS spring Meeting15 Optimal ratio of LAB and Alumina for purification - Optimization Find optimal ratio of LAB and Al 2 O 3 Using column adsorption method, take purified LAB for each time, naming as batch1, batch2,…  total 10 batches. Measure the absorption spectrums and calculate the attenuation lengths (at 420 nm) of each batch  1:5 (alumina : LAB)

16. 2007 KPS spring Meeting16 Radiopurity level  10 -13 g/g (Th, U, K) : Daya Bay/Double Chooz S/N > 100 (DB, DC) RENO rediopurity level 측정 : ICP-MS( 기초과학지원연구소 ) 정제 방법 개선 후 정밀도가 높은 장비로 측정 예정 Radiopurity level in LS K [g/g]Th [g/g]U [g/g] Mineral Oil0.77x10-6< 2x10-9< 5x10-10 From Daya Bay TDR

17. 2007 KPS spring Meeting17 Radiopurity level  10 -13 g/g (Th, U, K) : Daya Bay/Double Chooz S/N > 100 (DB, DC) RENO rediopurity level 측정 : ICP-MS( 기초과학지원연구소 ) 정제 방법 개선 후 정밀도가 높은 장비로 측정 예정 Radiopurity level in LS K [g/g]Th [g/g]U [g/g] Mineral Oil0.77x10-6< 2x10-9< 5x10-10 From Daya Bay TDR

18. 2007 KPS spring Meeting18 Gas Chromatography (GC) with Mass Spectrometry (MS) Measurement of LAB Component using GC-MS Motivation : calculation of # of proton, H/C LAB : (C 6 H 5 )C N H 2N+1 Gas Chromatography Mass Spectrometry (MS)

19. 2007 KPS spring Meeting19 Measurement of LAB components LAB : (C 6 H 5 )C N H 2N+1

20. 2007 KPS spring Meeting20 C 16 H 26 C 17 H 28 C 18 H 30 C 19 H 32 7.17% 27.63% 34.97% 30.23% LAB components with GC-MS LAB : (C 6 H 5 )C N H 2N+1 # of H [m -3 ] = 0.631 x 10 29 H/C = 1.66

21. 2007 KPS spring Meeting21 KF-50 KF-70 Measurement of Mineral Oil components Difficult to figure out Component of M.O * KF-50,KF-70 : 서진화학 M.O

22. 2007 KPS spring Meeting22 w/o N 2 flushing w/ N 2 flushing Effect of Nitrogen flushing & purification Light Yield

23. 2007 KPS spring Meeting23 100% 82% 96% N 2 flushing is crucial Effect of Nitrogen flushing & purification Light Yield

24. 2007 KPS spring Meeting24 Summary and Plan  Current Gd (un)load LS R&D Status Investigation of Solvents, Fluors LS mixing procedure developed Purification method developed Start Gd loading into LS with Russian Group  Long term R&D Plan Investigation of radiopurity Developing mass production techniques (purification, filling, etc.,) Long term stability R&D (Light Yield, optical properties) Stability is the most important !!!