1. (on behalf of the RENO collaboration)
Energy calibration
June-Ho Choi
Dongshin University
(on behalf of the RENO collaboration)

2. Calibration system

3. Calibration system(1D)
Gamma catcher
Teflon weight
Radioactive source
timing pulley
wire pulley
Target
servo motor
Servo driver
DC adaptor
controller
control pc

4. Calibration system(1D)
Target
(mm)
Catcher
1200
1650
800
1100
400
550
-400
-550
-800
-1100
-1200
-1650

5. Calibration system(3D)
horizontal probe handle
servo for vertical moving
control box
arm holder
vertical slide panel
shaft
servo for azimuthal rotation
extension arm
main vertical arm
sub vertical arm
slider
arm connector

6. Calibration system(3D)
Target
200
400
400
400 mm

7. Energy reconstruction
Qtot : sum of hit PMT charges greater than 0.3 p.e. in a time window of
-100 to +50 ns.
Temporal charge correction(IBD n-Gd)
p.e to MeV conversion
function
E(MeV)
Law Qtot
Corrected Qtot
PMT gain change
Removal of Flashing PMTs
The decrease of the LS attenuation length

8. Temporal charge correction

9. Source data taking & calibration
We have 9 radioactivity source for calibration points for energy calibration.
- Cs, Ge, Co, Cf, AmBe, NiCf, Mn, Na, Zn
Source data taking has been performed using by 1D calibration system regularly
(every month)
Gain calibration was done by Cs(single photon) source after data taking
Energy calibration

10. Radioactivity Sources
Isotope
Activity (Bq)
Half-life
Emissions
Energies (MeV)
production
137Cs
37 kBq
30.1 years
Single gamma
0.662
SPECTRUM TECHNIQUES
60Co
5.27 years
Multi gamma
1.173, 1.332
68Ge
40.48 kBq
270.8 days
0.511
Eckert & Ziegler
252Cf
7.4 kBq
6.245 years
Neutron
Neutron capture
2.223(n-H) ,
7.937(n-Gd)
54Mn
312.3 days
0.835
65Zn
245 days
1.116
22Na
2.6 years
1.821
241Am-Be
340 kBq
432.2 yesars
4.95
RENO
210Po-Be
37 MBq
138 days
Cf-Ni
< 7.4 kBq
8.99

11. Gain calibration
Near detector
Far detector

12. Procedure of energy calibration
We use 6 points for energy calibration.
1) 137Cs(0.662MeV),68Ge(1.022MeV), 60Co(2.5057MeV),
Neutron capture (n-H : MeV , n-C: 4.95 MeV , n-Gd: 7.937MeV (target)
n-Ni : 8.539MeV( gamma catcher) )
2) Data was taken at center position( target & gamma catcher) every month
3) Average p.e of source data points
4) Correction effect from calibration source(MC)
 Energy absorption of source wrapper & container
 Quenching effort of multi gamma
 p.e response of different particle (gamma .vs. positron)
 Energy conversion of center to uniform
5) NPE to MeV conversion function :
6) Cross-check with electron energy spectrum from β‐decays from 12B and 12N

13. Procedure of energy calibration
Corrected Qtot(p.e) of radioactivity sources
Energy absorption of source package & container
Quenching effort of multi gamma
p.e response of different particle (gamma .vs. positron)
Energy conversion of center to uniform
Corresponding IBD Prompt Qtot(p.e)
Fitting with non-linearity function

14. p.e distribution of radioactivity sources (Target)
137Cs
68Ge
(0.662 MeV)
(1.022 MeV)
Po-Be
(4.95 MeV)
60Co
252Cf
( MeV)
(2.223 & MeV)

15. p.e distribution of radioactivity sources (Target)
54Mn
65Zn
(0.535 MeV)
(1.116 MeV)
65Zn
(1.116 MeV)

16. p.e distribution of radioactivity sources (gamma catcher)
137Cs
68Ge
(0.662 MeV)
(1.022 MeV)
60Co
252Cf
( MeV)
(2.223 MeV)

17. p.e distribution of radioactivity sources (gamma catcher)
54Mn
65Zn
(0.535 MeV)
(1.116 MeV)
65Zn
(1.116 MeV)

18. [Energy absorption of wrapper & container]
Source wrapper
68Ge
Source container

19. [Energy absorption of package & container]Cs
- Without capsule
- With capsule Co
- Without capsule
- With capsule
1.7%
1.6%
Source container
Air
Source package

20. [quenching effort of multi gammas]Co
- Single gamma
- Two gamma
- Single gamma
- Two gamma
4.46%
3.08%

21. [Quenching effort at each energy]
- Gamma
- Positron

22. [p.e. response of different particles]
- Gamma
- Positron
- Proton

23. γ→e+= Source MC (E) Positron MC (E−1.022Me𝑉)
Conversion of gamma to IBD prompt energy
γ→e+= Source MC (E) Positron MC (E−1.022Me𝑉)
Source
MC (center)
Positron
± 0.094
± 0.085

24. Center→Uniform= IBD Delayed P.E. nocut Fitting Function(−1000 mm)
Energy conversion of center to uniform
Center→Uniform= IBD Delayed P.E. nocut Fitting Function(−1000 mm)
Uniform
1000 mm
1000 mm
Center

25. Nonlinear response of scintillation energy
(Target)

26. The Fitted parameter values of the energy conversion function (Target)
Far
Near P0
275.9±1.0
270.1±1.3 P1
(1.698±0.151)x10-2
(1.701±0.247)x10-2 P2
(1.228±0.123)x10-4
(1.161±0.117)x10-4 P3
(1.735±0.176)x10-4
(1.794±0.299)x10-4

27. Nonlinear response of scintillation energy
(gamma catcher)

28. The Fitted parameter values of the energy conversion function (Catcher)
Far
Near P0
284.2± 3.6
277.2 ± 2.3 P1
0.022 ± 0.007
0.019 ± 0.002 P2 ± ± P3 ± ±

30. 137Cs , 60Co
252Cf
Source container
68Ge

31. Low Energy Electron Quenching
Light yield of scintillator
In low energy region
Collision stopping power of LS is
function of electron energy
Different by matter
Berger & Seltzer Equation
<composition of LS>
LAB
PPO
bis-MSB
860g/L
3g/L
0.03g/L

32. Measurement of Birk’s Constant
<Experimental Setup>
Source : 137Cs
Energy of electron = 662KeV – Ge Detector
Light yield of LS = PMT ADC
137Cs
Ge detector calibration is done using
known gamma source, 137Cs, 22Na
137Cs : 662KeV, 22Na : 551KeV
22Na

33. Measurement of Birk’s Constant
Energy of electron [KeV]
Light Yield
Light yield over Energy of electron
e e+00
KB = cm/KeV
Energy of electron [KeV]

34. Summary table 𝑃. 𝐸 𝑀 𝑒𝑉=𝑅𝑎𝑤 𝑝.𝑒. × 𝐶 𝑐𝑒𝑛𝑡𝑒𝑟−𝑡𝑜−𝑈𝑛𝑖𝑓𝑜𝑟𝑚 × 𝐶 𝛾−𝑡𝑜− 𝑒 +
DATA
137Cs
68Ge
H-Capture
(2.223MeV)
60Co
C-Capture
(4.95MeV)
Gd-Capture
(7.937MeV)
FAR
Raw p.e
± 0.769
± 2.074
± 2.307
± 3.454 ±
2020.5
± 0.798
p.e MeV
± 1.162
± 2.101
± 1.066
± 1.454
± 2.848
± 0.111
NEAR
± 0.723
± 1.738
± 2.342
± 3.116 ±
± 0.252
± 1.068
± 1.749
± 1.042
± 1.288
± 2.577 ±
𝑃. 𝐸 𝑀 𝑒𝑉=𝑅𝑎𝑤 𝑝.𝑒. × 𝐶 𝑐𝑒𝑛𝑡𝑒𝑟−𝑡𝑜−𝑈𝑛𝑖𝑓𝑜𝑟𝑚 × 𝐶 𝛾−𝑡𝑜− 𝑒 +