Neutrino experiment Design Requirements for Jinping Underground Neutrino

Neutrino experiment Design Requirements for Jinping Underground Neutrino Experiment Guanghua Gong Dept. of engineering Physics, Tsinghua University 2015. 06. 05

Outline Physics requirements Ø Detector concept Ø LS/Water/Wb. LS Ø Purification system Ø PMT Ø Electronics/Trigger/DAQ Ø Prototypes Ø

Physics requirements Ø Fiducial mass • >1 Kt Ø Energy range: • 0. 1 Me. V – 100 Me. V Ø Energy resolution: • 500 – 1000 PE/Me. V Ø Directionality: • 20°for E> 5 Me. V Ø Particle identification • Cherenkov and scintillation separation • Gamma vs. electron vs. alpha-proton-nuclear-recoil Ø Calibration • Energy response nonlinearity <1% • Position reconstruction bias <1 cm (@r=6 m)

Detector(s) arrangement 0 m tu e nn l 13 Option 1: dual detectors Option 2: single detector 2020/9/17 Depends on civil situation 4

Target Mass: Sphere or Cylinder Sphere 2020/9/17 5

Detector concept cylinder sphere

Major detector components From inner to outer Target material Acrylic vessel Water buffer PMT SS framework Black shield Veto PMT Water buffer Tyvek reflector SS vessel

Target material Ø Assumptions • PMT QE : 20% (35% for HQE PMT) • Coverage: 50% ~ 80% Ø To reach 500~1000 PE/Me. V resolution, light yield of target material 2000~10000 photons/Me. V

Target material : Water/LS/Wb. LS Target range Minfang Yeh

More information from Wb. LS Ø Cherenkov lights provide direction info. for charge particles. • non-solar background suppression • Electron/Photon separation Ø Ø Cherenkov light must dominate in the 1 st 10 ns over scintillation light Scintillation requirement • Light yield • Ʈ > 100 ns (if S=C in 10 ns) Slow scintillation light fast Cherenkov light

PMT requirements Dimension: 8” / 9” / 20” Ø QE: >20% Ø TTS: <5 ns Ø • Related to the S/C separation • Longer Ʈ of Wb. LS will relax the requirement FWHM: <10 ns Ø Low radioactivity background Ø Coverage: 50% ~ 80% Ø • 2500(20”) ~ 15000(8”)

Calibration Energy response non-linearity : <1% Ø Position reconstruction bias: <1 cm (@r=6 m) Ø • (6. 02/6)**3 -1 = 1% Optical and radiation sources Ø Rope loop for 4 -π deployment Ø

Electronics/trigger/DAQ/DCS Ø FADC with 1 Gsps/12 b readout of each PMT • Patten recognition, C/S separation • information reconstruction, better event quality Ø Trigger-less scheme • Self-trigger for each PMT, event selection by CPU • PMT Dark noise and long scintillation lifetime • Challenges for DAQ Ø Electronics under water • Better signal quality • Engineering challenges • seal, cable/connectors, reliability

Prototype(s) 20 L 2014 Cosmic with Telescope Topic: Wb. LS Light yield See Mohan’s talk 20 t 1 t 2015 30 PMT + Wb. LS Topic: α/β/γ separation, Direction recon, particle identification Relocate able in container 2016 200 PMT + Wb. LS Topic: radioactivity background PMT study, Material purification Engineering verification

Other topics Ø Purification • Water / scintillator / nitrogen Calibration Ø PMT protection Ø Magnetic shielding? Ø thermal environment / temp. control Ø Low radioactivity materials Ø Infrastructure Ø and many…. . Ø

Summary CJPL-II provides great opportunity for lowbackground neutrino experiment. Ø Feasible conceptual detector design, detail scenario depends on civil situation Ø Major experimental requirements settled down Ø Prototypes testing are under going Ø Ø Many aspects are not started ….

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