Simulation study of RENO-50
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Transcript of Simulation study of RENO-50
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Simulation study of RENO-50
Jungsic ParkSeoul National University
RENO-50 International WorkshopJune 13-14, 2013
Hoam Faculty House, Korea
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Preliminary RENO-50 Detector Concept
25 m27 m
RENO-50
25 m27 m
LS (10 kton)15000 10”
PMTs
Mineral Oil
32 m
32 m
Water
KamLAND x 10
1000 10” OD PMTs Concentric cylindrical detector.
- Initial concept is same as RENO.- No gamma-catcher region and filled with Liquid Scintillator Only.
- Install 15000, 10 inch inner PMTs and 1000, 10 inch outer PMTs.
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RENO-50 Detector with Monte-Carlo
Target : Acrylic, 25m*25mBuffer : Stainless-Steel, 27m*27mVeto : Concrete, 32m*32m
PMT attachment scheme.
Barrel : 50 raw * 200 column (9*26 for RENO)Interval of each PMT center is 50cm.
Top & Bottom
2501 PMTs for each region. (60 for RENO)45cm
45cm
2700cm
2700cm
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Energy resolutionAssume that optical properties and thickness of detector materials are same as RENO detector.
For the energy resolution, we generate single gamma of various energy (1~10MeV)at the detector center.
Using the initial concept, we get~7% resolution @ 1MeV and calculated PMT coverage is 24%. PMT coverage : 23.95%
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sensitivity test by Monte-Carlo.
Using the Pseudo-experiment , check the sensitivity of θ12 and Δm221 measurement.
True value : varied varied
002320
0000760
1002
855602
231
221
132
122
.
.
.sin
.sin
m
m
fixed
Measurement of θ12 and Δm221
Assume 10kton * 20GW * 5years exposure
002320
1002
855602
0000760
231
132
122
221
.
.sin
.sin
.
m
m
fixed
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222
2
26
112
2
11
)()()(
)*(
))(*)(**)(*exp*(
reb
bbkgbkgsignal
roscirbkgsignal
feb
NNN
funcefNbNN
Nsignal = 30000 (oscillation , 10kton, 20GW, 5years, 100% efficiency & Livetime )Nbkg = 300 (~1% level)
ε = 1.0 (detection efficiency)b,e, f : pull parameter (e : efficiency, f : reactor)σeff = 0.015 (1.5%)σr = 0.03 (current limit : ~3% goal is below 1%)σb = 0.05 (5%)
Nexpr : Expected event number without oscillationFuncosci(θ12) : oscillation / No oscillation (fraction)
Χ2 fitting with pulls for θ12
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True value : 0.8556Fitting value : 0.8552 +- 0.0162 (1σ) ~1.89%
Χ2 fitting result
σeff = 0.015 (1.5%)σr = 0.03 (3%)σb = 0.05 (5%)
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Statistics part decrease very rapidly.The main portion is systematic part.
Statistical part only for θ12
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Uncertainty of detection efficiency and reactor uncertainty are both important.
Systematical part for θ12
We assumed σb is zero.
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222
2
26
1
22111
1
2
)()()(
)*(
))(*)(**)(*exp*(
r
f
e
e
b
b
bibkgNi
bkgNisignalN
rmoscifuncefr
iNbibkgNi
signalNNbin
i
For the Δm221 , we should use the spectrum shape.
N_signal, N_expr N_bkg should be considered bin by bin.Assumed that background is flat. (same number for each bin content)
50bin/MeV 1.8 ~ 8 MeV range cut
Χ2 fitting with pulls for Δm221
ε = 1.0 (detection efficiency)b,e, f : pull parameter (b: background, e : efficiency, f : reactor)σeff = 0.015 (1.5%)σr = 0.03 (current limit : ~3% goal is below 1%)σb = 0.05 (5%)
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Systematical part for Δm221
True value : 7.6e-5
Fitting value : (7.598 +- 0.048)e-5 (1σ) ~0.64%σeff = 0.015 (1.5%)σr = 0.03 (3%)σb = 0.05 (5%)
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Expected neutrino visible energy spectrum of RENO-50
002320
0000760
1002
855602
231
221
132
122
.
.
.)(sin
.)(sin
m
m
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Energy resolution plays a crucial role to RENO-50Solid line : Normal HierarchyDashed line : Inverted Hierarchy
So, How can we increase the energy resolution ?
@1MeV
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1. Increase the attenuation length of Liquid Scintillator. - 1.5 times current value : 18.7m @ 430 nm - 2.0 times current value : 24.9m @ 430 nm
2. Increase the PMT Quantum Efficiencies. - 1.25 times current value : 30.0% @ 427 nm - 1.5 times current value : 36.0% @ 427 nm
3. Increase the PMT coverage. - 25000 PMTs : 40.86 % coverage
Cf) Default value 24% PMT coverage Att.length of LS is 12.4m @ 430 nm PMT QE is 24% @ 427 nm
Improve the optical properties
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24% @ 430 nmMaximum 25% @ 390nm
PMT Quantum Efficiency of R7081 Hamamatsu 10 inch PMT
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Mineral OilLiquid Scintillator
Liquid Scintillator : 12.4m @ 430 nmMineral Oil : 17.0m @ 430 nm
Attenuation Length of Current Materials.
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Increase the Attenuation Length
Attenuation length should be comparable of detector size.
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Increase the PMT Quantum Efficiency
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Increase the PMT Coverage
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Applying all the Improvement Effect
It’s very challenging task to acquire ~3% energy resolution.
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Summary
RENO-50 Monte-Carlo preliminary version was made.
Statistical uncertainty decrease rapidly within few years.
Detection efficiency and reactor uncertainty contributes to systematic a lot.
Including other uncertainty parameters is still keep going.
3% energy resolution is very challenging task. We should improve all the Optical properties about twice. It’s time to think about the improvement method all together.