Status of JUNO Liquid Scintillator Boxiang Yu on behalf of JUNO LS - PowerPoint PPT Presentation

Status of JUNO Liquid Scintillator Boxiang Yu on behalf of JUNO LS group FroST16 @Fermilab; 2016-3-19 1

JUNO Jiangmen Underground Neutrino Observatory • Collaboration → June 2014 • Civil engineering → end 2014 • Data taking → 2020 2

What What will JUNO JUNO get? 3

Electronics Detector Vessel (Central detector) Filling + Calibration Overflow Top Tracker Centra tral l detecto ector AS: ID35.4m .4m 43.5m Acrylic sphere+ SSLS: LS: ID40.1m 1m 20kt Liquid Scin+ ~17000 20” PMT+ ~34000 3 ’’ PMT Wate ter r Cherenko nkov ~2 000 20’’ PMT D43.5m AS: Acrylic sphere; SSLS: stainless steel latticed shell 4

JUNO LS requirement 20 ktons LS for JUNO detector Requirements for JUNO LS: ～ 1200 p.e./MeV High light yield: Long attenuation length: >22m Low radio-impurity: 238 U, 232 Th <10 -15 g/g 40 K <10 -16 g/g The most important thing is the purification of LAB/LS 5

JUNO-LS production flow chart Preliminary design  20kton LS will be purified LAB A.L. : 13m->25m -LS A.L. increased by Al2O3 column ; -Distillation, water extraction and steam stripping will be used to reduce the radiation background of JUNO LS; 6

LS recipe experiment result • Recipe: LAB + PPO + bisMSB • The PPO concentration: 3g/l PPO; (Preliminary) • The Bis-MSB concentration is still undecided, it will be decided after pilot plant experiment; • These result based on small size detector( Φ 5cmX12cm) ； Bis-MSB concentration Preliminary Result PPO concentration 3g/l PPO 7

FLuors for JUNO LS 8

LAB/LS Purification experiment Small column optical purification Experiment motivation Experiment motivation ： • Compare the different filtration material, such as active carbon, resin and Al2O3; • Al2O3 purification ability, one volume Al2O3 can purify 10 Volumes LAB ？ 20BVs ？ Or 30BVs ？ ) (BV is bed volume, volume of AL2O3); Small size Experiment setup 9

Filtration material contrast experiment Al2O3 Compare Al2O3 with Silica gel The result show: and active carbon  After several times contrast experiment, Al2O3 is the best selection; Al2O3  The different Al2O3 has been tried and the best company has been found; Compare Al2O3 with resin 10

LAB contrast experiment Special LAB (A.L.= 15m ) and Commercial LAB (A.L.= 5m ) A.L.@430nm A.L.@430nm The change is little. The change is obvious. Special LAB (After purification) Commercial LAB (After purification)  So the quality of raw LAB is very important for optical purification ；  One volume AL2O3 can purify about 35 volumes for special LAB ; 11

Small scale distillation tests: Fausto O. - Aldo R. The distilled samples had showed better optical characteristics (both absorption and emission) than the original not purified ones. No deterioration of the LAB was noticed. We also found a slight improvement in the absorption spectra on the Nanjing LAB pre-purified by Al 2 O 3 column Main distillation parameters: - Pressure: 0.4 mbar (very low - > T ≈ 110 °C) - Claisen condenser (30 cm) - Vigreux column (15 cm – internal reflux) - System to collect different distillate fractions 12

Small scale distillation tests: Fausto O. - Aldo R. Distillation tests: absorption spectra in a 10 cm-path quartz cell on the distilled Nanjing LAB pre-purified by Al 2 O 3 4.0 3.2 0.12 before distillation after distillation absorbance 2.4 absorbance 0.06 1.6 0.00 0.8 350 400 450  / nm 0.0 280 320 360 400 440 480 520 560 600  / nm 13

Small scale water extraction test • Radon was loaded to LS, then A small-prototype LS purified by water extraction prototype; • Water extraction plant can remove 238Th, 232U and 40K. • Measure the purification efficiency at different conditions, and optimize the parameters. Parameters: Flux Rate: 1~2L/h Disc Series: ~25 stages 14

Water r ext xtracti tion n proto totyp ype exp xperi riment t res esult Water Extraction temperature result • The experiment result show that the purification efficiency can reach to 85% at room temperature (Saving underground power). 15

Pilot plant of JUNO LS DYB AD  Four purification system will be tested (Al2O3 column, distillation, water extraction and steam stripping);  Flow rate is 100 ～ 150 L/h;  Every system will checked respectively , then the purified LS by whole system will be filled and checked by DYB AD detector; 16

JUNO Pilot plants Hall (DYB LS Hall) Al2O3 column Steam stripping Distillation Water extraction 17

AL2O3 column pilot plant Al2O3 column Al2O3 column plant is based on the “absorption” technique to 3D Design remove optical impurities and increase the A.L. of LAB LAB and Al2O3 Mixing tank System Specification ： Full size prototype ； Column H:D=5:1 ； Column Diameter:500mm ； Column Height:3000mm ； Two stage Filter:1um filter +200nm filter (or 50nm filter) Purified LAB tank Control Box 18

Distillation pilot plant Distillation pilot plant main parameter: • Remove heavy metal, improve transparency • Flow rate 100 l/h (20 m 3 in less then 10 days) • 6 physical trays • 1-2% adjustable bottom column discharge • High reflux rate (nominal 25%) • Be installed in this month Process parameters High Diameter Pressure Temperature Scint. Flux Scint. Reflux Max Gas flow N° Trays [kg/h] [m] [mm] [mbar] [°C] [l/h] [l/h] Distillation 4 250 6 60 220 100 25-50 1 19

Water extraction Pilot Plant Water extraction pilot plant is the prototype. The efficiency of removing 238 U, 232 Th and 40 K will be gotten. It will be installed in next month. item Parameter Flux Rate 170 L/h Diameter of column 150mm Height of Column 3.5m Speed 0~200r/min Paddle Stages 27 Physical trays >5 RT~80 0 C Temperature *We hope the purify efficiency is 85% at room temperature, and can reach 90% at 80 0 C (for 212 Pb). 20

Steam Stripping pilot plant Stripping plant remove the impurities : Ar, Kr and Rn. Water steam can avoid to use huge quantity of nitrogen in underground (safety). High temperature (100 °C) for higher column efficiency (low LAB viscosity) • Partial vacuum (around 300 mbar) • Both steam and nitrogen stripping could be tested in the plant Process parameters High Diameter Pressure Temperature Scint. Flux Steam Flux Gas flow N° Trays [m] [mm] [mbar] [°C] [l/h] [g/h] [g/h] Structured Stripping 5.5 60 300 100 100 250 250 packing 21

High pure nitrogen system - The nitrogen purification pilot plant developed; it will supply the high pure nitrogen for nitrogen blanket of pilot plant; - It can be used as stripping gas (Nitrogen Stripping); LTA technology Pilot plant Design Drawing -Low background CarboACT active carbon was used; 22

JUNO LS in DYB AD (Antineutrino Detector)  The purified LS will be filled in DYB AD, AD will be used to check the Pilot plant purification result, including LS optical quality and radiation background;  The detection limit of 238 U and 232 Th is 10 -15 g/g for DYB AD detector from 30 days data; 30 days data Simulation result 23

Rayleigh scattering measurement  Rayleigh Scattering in LS is considered to be caused by the fluctuations and random orientation of molecules within a sufficiently small volume.  With Rayleigh scattering taken into account, more photons can be detected by PMTs in the dark zone. 24

Rayleigh scattering result  Rayleigh scattering is measured under ESC(Einstein-Smoluchowski-Cabana formula) model. Four different experimental measurements have been performed. The results are consistence with each other in one sigma.  Model independent experiments are ongoing in JGU, WHU and UCAS. 25

Milestones of JUNO Start end 1 Underground lab construction 2015.1.1 2018.2.23 3 CD & water poll equipment installation 2018.2.28 2019.3.1 8 PMT testing 2017.4.4 2019.1.30 10 CD & VETO PMT installation 2019.3.4 2019.7.1 11 Readout electronics design finalized 2017.1.2 2017.5.31 13 LS purification system installation 2017.10.15 2018.12.25 15 CD & water pool cleaning 2019.8.1 2019.9.1 19 AD & VETO water filling 2019.9.4 2019.11.1 20 LS filling 2019.11.4 2020.2.3 21 Test run 2020.2.4 2020.5.4 26

Summary • Huge LS detector: -20 ktons with precise energy resolusion:3%/sqrt(E) • Transparent LS: attenuation length over than 22m • Low radio-impurity: 238 U, 232 Th <10 -15 g/g 40 K <10 -16 g/g • Five pilot plants have been completed, pilot plants experiment will be completed in 2016 • LS filling in end of 2019 and taking data in 2020 27

Thanks! 28

Backup 29

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Characterization and physical property study UV-Vis measurement •UV -Vis measurement: IHEP, University of Perugia and INFN – Commercial instruments, small amount of samples, rapid measurement – Relative measurement – Difference caused by different instrument 33

LS A.L. measurement system Fiber  Check the AL2O3 column LED Len Electric purification ability; platfor Filter m Stainless Amplifer steel tank Hardware setup ： • LAB tube length 1.8m; Pulse • Wave length:430nm ± 5nm; generator stepper motor Stainless • Systematic error: ～ 2m@20m; steel tube HV Digitizer PMTs 34

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