1. Neutrino Oscillation
description
Transcript of 1. Neutrino Oscillation
1. Neutrino Oscillation
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θ13
θ12
θ23
θ12
θ13
θ23
Gaol of RENO experiment = θ13
1. Neutrino Oscillation
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νe
νe
νe
νe
νe
DistanceProb
abili
ty ν
e
disappearance
1. Neutrino Oscillation
2. Neutrino Detecting
Pn
Prompt signalΣE ~ 1.022MeV
Delayed signalΣE ~ 7.96MeV
Neutron captured by Gadolinium
e~30μs
Gd
γe γ γ
γγ
γ
2. Neutrino Detecting
1 MeV 8 MeV6 MeV 10 MeV
Arbi
trar
y
Flux Cross Section
From Bemporad, Gratta and Vogel
▶ Expected measurable neutriron spectrum
▶ Prompt signal ▶ Delayed signal
2. Detector & Data taking #354 10” ID PMTs : 14% sur-face coverage #67 10” OD PMTs Both PMTs : HAMAMATSU, R7081
LAYERD
(cm)
H(cm) vessel Filled
withMass(tons
)
Target 280 320 Acrylic Gd(0.1%) +LS 16.5
Gamma
catcher
400 440 Acrylic LS 30.0
Buffer 540 580 SUS Mineral oil 64.4
Veto 840 880 Concrete water 352.
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Radioactive Source div-ing
2. Detector & Data takingH V
Decou-pler
HV supply
Signal outQbee(DA
Q)Signal transform to Digi-tal
Raw Data1. Ch2. Time 3. Signal
size
RFM;root file
(reformat)
Online PC
Offline PC
PRDSelecting in-teresting in-formation
Reduc-tionSelecting neu-trino event
event
1 2 …ch 034 064 .
time . . .size . . .
ntuple formbinary
Calibration analysis
NPE table
3. Calibration
Calibration 3 stepQBEE calibration Gain matching Energy calibration E
Detector
Deposit Energy
PMT
Unknowing Energ[MeV] photoelectron current ADC count
Qbee
f(x)’
f(x)
f(x)’’
3. Calibration▶ QBEE Calibration imagine input charge(current) → output count : count pC(current)
f(x)
3. CalibrationPhotocathode : Alkali (1group) 2.xxeV work function
dynodes
electron multiplication1
2
3 nNel
E=hc/λ ~1240eV·nm/400nm ~3eV current
P M TpCC 6.110106.1 719
Ne=GainⅹNp.e
▶ Gain variation → regular checking
3. Calibration▶ Gain matching Single Photo-electron measurement
3. Calibration▶ Gain matching
<Coverage ~ 12.6%>
MeVepEQ
MeVep .250)2.0(~.126.0.10000~9000
pC p.e f(x)’
137Cs is satisfied with (354 PMT > p.e) condition
3. Calibration▶ Gain matching
pC p.e f(x)’
3. Calibration▶ radio active souce for Energy calibration
137Cs
FarNear
0.662 MeV
60Co
2.506 MeV
3. Calibration▶ radio active souce for Energy calibration
68Ge1.022 MeV
3. Calibration▶ radio active souce for Energy calibration
Gd(n,g) neutron capture signal
p(n,g) neutron capture signal
FarNear
2.2 MeV
7.96 MeV
Sources @ center. Near/Far show similar spectra.
3. Calibration▶ Energy calibration
p.e MeV f(x)’’
PE to MeV Function(p2*X2+p1*X+p1)
3. Calibration
▶ Detector stability
Change p.e/MeV
4. MC simulation▶ RENO MC simulation : based on GLG4SIM geant 4 program. derived from KLG4SIM of KamLAND collaboration.
4. MC simulationMC_single PMT p.e distribution
Real_data_single PMT p.e distribution
4. MC simulation
4. MC simulation▶ Upgrading MC
4. MC simulation▶ Cs-137 MC
4. MC simulation▶ Ge-68 MC
4. MC simulation
Cs-137 : 1.7% Ge-68 : 3.2%
Co-60 : 1.6%
▶ Reduced Energy
5. Results▶ Improvement tuning
Cs-137 Ge-68 Co-60
5. Results▶ Improvement Energy calibra-tion
5. Results▶ Improvement Energy calibra-tion
summary▶ To get energy information, we have to do calibration process
1. Qbee calibraiton 2. Gain matching 3. Energy calibration
▶ Upgrading MC for radioactive source data Application for capslue & container
Back up
1. Neutrino Oscillation)(||| 2
P
Pth : Reactor Thermal power f : Fission fraction of each isotope (reactor core simulation of Westinghouse ANC, and has error U235: 3.3%, Pu239: 4%, U238: 6.5%, Pu241:11%)ϕ : Interacted Neutrino Spectrum of each fission isotopeE : Energy released per fission
thPN
Arbi
trar
y
Flux Cross Section
From Bemporad, Gratta and Vogel
The observable antineutrino spectrum is the product of the flux and the cross section
The most probable neutrino energy interacting at a detector is 3.8 MeVThe cut-off at 1.8 MeV is due to the minimum neutrino energy required for IBD event.
Expected measurable neutriron spec-trum
Expected S1 & S2 spectrum
(1 MeV 2γ’s) + (e+ kinetic energy), E = 1~10 MeV
1 MeV 8 MeV
6 MeV 10 MeV
e p e+ + n (prompt) + p D + (2.2 MeV) (delayed) + Gd Gd* Gd + ’s(8 MeV) (delayed)
n+p→D+ γ(2.2MeV), n+Gd→Gd+γ’s(8MeV)
It happens that in the beta decay of 137Cs, the product barium nu-cleus is left in an "excited" state. This decays in a few minutes back to the "ground" state of the barium nucleus, emitting a pho-ton of fairly high energy, which is a "gamma" rays of energy 0.66 MeV.
Radioactive Sources 137Cs
0.66 MeV ↑
Radioactive Sources 60Co
Multiple Gamma =2.506 MeV
Germanium-68 decays by pure electron capture (EC) to the ground state of 68Ga with a half-life of 270.95(16) d. Gallium-68 in turn decays with a half-life of 67.71(9) min by a combination of EC and positron emission primarilyto the ground state of 68Zn.
stopped positron signal using 68Ge source→positron threshold
Radioactive Sources 68Ge
Radioactive Sources 252CfWhen a 252Cf nucleus spontaneously fssions, it emits on aver-
age 4 neutrons and approximately 20 low energy gamma rays. These ssion neutrons are used to calibrate the neutron detection efficiency.
Detector Stability
Detector Stability
Cs137 Co60
Holder : Poly(methyl methacrylate) 밀도 1.18g/cm3
Cover : Epoxy 라고만 나옴
: Cs137 과 Co60 은 같은 모양입니다 .
Epoxy
Radioactive materials
Label
< 단면 >25.4mm
4.445mm
Holder
6.35mm
0.508mm
Ge68
Source : 밀도 9 mg/cm2 , 두께 0.254mm 의 aluminumized Mylar(polyester) disk 에 3mm 지름으로 deposit 됨
Cover : 1. 밀도 0.9 mg/cm2, 두께 ( 안나옴 ) 대략 0.25mm 의 polyimide Film(Kapton)
2. 밀도 , 두께 안나옴 Decal(film 종류 ) // film 개념이라 두께에 대한 정보가
없는듯함 사진에 흰색 Label 지가 Decal 같음
Retaing Ring : 제질 안나옴 Aluminum Holder : aluminum
Disk 총 두께 ~ 0.76mm 지름 = 23.8mm
3mm
~ 알루미늄 hodler 얇은 부분 0.4mm
40mm
3mm( 두께 )
20mm
8mm( 뚜껑두께 )
원 근거리 소스 아크릴 원통
3mm( 밑 부분 두께 )
4mm
20mm 정육각형8mm( 뚜껑두께 )
4mm
3mm
7mm
호의 길이 20mm
8mm2mm
뚜껑 위면뚜껑 단면
ConvolutionsImagine that we try to measure a delta function in some way …
Despite the fact that the true signal is a spike, our measuring system will al-ways render a signal that is ‘instrumentally limited’ by something often called the ‘resolution function’.
True signal Detected signal
True signal Convolved signal
Resolutionfunction
If the resolution function g(t) is similar to the true signal f(t), the output function c(t) can effectively mask the true signal.
http://www.jhu.edu/~signals/convolve/index.html
Convolutions
3. CalibrationPhotocathode : Alkali (1group) 2.xxeV work function
dynodes
electron multiplication1
2
3 nNel
E=hc/λ ~1240eV·nm/400nm ~3eV current
P M TpCC 6.110106.1 719
Ne=GainⅹNp.e