1. M-C simulation of reactor e flux;
Production of Electron Neutrinos from Reactor and the Physics Potentials
M-C simulation of reactor e flux;
Data analysis for the limits of electron neutrino magnetic moment and the radiative decay lifetime;
Some physics potential of reactor neutrino experiment.
XIN Biao / 辛 標
On behalf of TEXONO collaborator
China Institute of Atomic Energy/中國原子能科學研究院
Osaka

2. electron neutrino flux
Simulation of reactor
electron neutrino flux
Nuclear material
Fission products n
Structure material
Neutron sampling
Geometry description
Probability of EC decay
Electron neutrino flux
Physical model
n rich nuclei
－decay EC EC
Electron neutrino emission
n rich nuclei
－ decay
Stable isotope
even-even
Stable isotope
electron anti-neutrino emission

3. Direct fission product Direct fission product
M－C simulation ——source of
reactor electron neutrino Z
104Tc
18m
103Tc
50s
104Ru
stable
103Ru
39d
104Rh
42s
103Rh
104Pd
－decay of
fission product n EC － N
Direct fission product
Fission products
Structure material
7E-10 -
3E-10
<3E-8
235U
Y(Z, N)×PEC
(Per fission)
1.7E-6
1.3E-5
239Pu
1E-7
1.2E-8
6.0
1.26
128I
4E-8
0.3
0.88
110Ag
1E-9
1.7
1.9
108Ag
7E-8
0.4
1.15
104Rh
<1E-5
0.2
87Sr
1.4E-5
0.005
0.53
86Rb
Y(Z, N)
PEC(%)
QEC(MeV)
Direct fission product

4. M－C simulation ——source of reactor electron neutrino
Neutron activation
fission products
QEC(MeV) σn
(barns)
PEC(%)
Y(Z, N)
(Per fission)
Y(Z, N)×PEC
235U
239Pu
104Rh
1.15
146
0.4
3.2
6.8
1.3E-4
2.7E-4
110Ag
0.88 89
0.3
0.03
1.1
9E-7
3.3E-5
122Sb
1.62
6.2
2.2
0.012
0.043
2.6E-6
1.0E-5
128I
1.26
6.0
0.12
0.52
6.9E-5
3.1E-4

5. enrichment of the nucleus (A-1 )
M－C simulation ——source of
reactor electron neutrino
Structure material
isotopes
Decay lifetime
T1/2
enrichment of the nucleus (A-1 )
QEC
(MeV)
PEC(%)
55Fe
2.7y
5.8
0.23
100
51Cr
27.7d
4.3
0.75
59Ni
7.6*104y
68.1
1.073 43
113Sn
115.09d
0.97
1.036 49
Contribution to electron neutrino ?

6. Contribution of different isotopes：
M-C simulation of reactor electron
neutrino ——physical model
Total flux of electron neutrino emitted from reactor structure material：
Ratio of neutron capture probability of each isotope in the different cell：
Contribution of different isotopes：
50Cr, 54Fe, 58Ni, 112Sn
activation isotopes in reactor structure material
51Cr + e V + νe
55Fe + e Mn + νe
59Ni + e Co + νe
113Sn + e In + νe

7. M-C simulation of reactor electron neutrino ——geometry description
50Cr in RC , SS & Zr-alloy;
54Fe in RC , SS & Zr-alloy;
58Ni in RC , SS& Zr-alloy;
112Sn in Zr-alloy;
Nuclear fuel material: UO2;
enrichment of 235U : 3 %;
Height of the fuel rod: 400cm;
Radius of the fuel rod: 0.45cm;

8. M-C simulation of reactor electron
neutrino ——geometry description
Reactor core: 624 lattices;
Fuel rod: 72 rods in each lattice;
Mass of UO2: 138 tons;
Control rods
And water
Zr-alloy
UO2

9. SIMULATION RESULT Neutron capture material weight (tons) isotope ratio
fcap
UO2
94.85
Fission -
1.003
238U
0.909
0.702
235U
0.028
0.240
Control rods and water
14.6
10B
0.010
0.312
54Fe
0.039
0.0003
50Cr
0.009
0.0008
58Ni
0.059
Stainless steel
(up and surround the reactor core)
1242
0.042
0.0095
0.0002
0.064
Zr-2 、Zr-4 alloy
44.9
Water in the reactor core
37.8
0.187
SIMULATION RESULT

10. Simulation result Preliminary
Electron neutrino are mainly contributed by Cr-50 in control rods;
Neutrino flux at detector position due to Cr-50 is: 1.2×109 cm-2s-1

11. Cross check & constraints
Leakage neutrons out of the reactor core < 1%;
K-eff: =1 for a critical system
Relative U-238 fission fraction: ~5%
U-239 production rates: ~0.6
Reference neutron spectrum

12. Cross check and constraints
Fission neutrons are mostly absorbed by fuel rods, control rods and water;
Cross check——
K-eff calculation;

13. Comments of cross check
Based on the simulation
The U239 production rate per fission is 0.7;
Φn=0.28*1014 for thermal neutron flux;
A control rod assembly fraction of ξ=0.1 contains 13 kg Cr-50 or N=1.6*1026;
The Cr-51 production rate per fission at K-eff=1(ξ=0.1) is ;
For 3 GW thermal power output, the Cr-51 production rate is Rnγ = 7.2*1016 s-1;
Only less than 1% neutrons leave the reactor pressure vessel enclosing the core.

14. Data analysis for reactor electron neutrino magnetic moment
Scattering
Electron recoil spectrum
e magnetic moment fitting

15. Data analysis ——spectrum processing
Normalized
Non(E) and Nbkg(E)
Non(E)－Nbkg(E)

16. Data analysis ——fitting of the e

17. Data analysis——neutrino decay (under way…)
Decay model
Decay lifetime (c.m./m)
Fitting of the experiment data

18. Physics potential
Can we increase the flux of the electron neutrinos emitted from a reactor ?
1 fuel rod replaced by Cr-50 rods, ……
2 fuel rods replaced by Cr-50 rods …
n fuel rods replaced by Cr-50 rods …

19. The reactor still work well
Physics potential
The reactor still work well
Neutrino flux can be enhanced up to ~103 times

20. Candidate isotopes to enhance theνe flux
Physics potential
Candidate isotopes to enhance theνe flux
Isotope
IA(%)
σnγ(barns)
Τ1/2
QEC(MeV)
BR(%)
Cr-50(n)
4.345
15.9
27.7d
0.753
100
Cr-50(p)
Cu63(n)
69.17
4.5
12.7h
1.675 61
Cu63(p)
Ge70(n)
21.23
3.15
11.43d
0.232
Ge70(p)
Eu151(n)
47.8
5900
13.516y
9.3116h*
1.874
1.92*
72.1
28*
Eu151(p)

21. Number of target nuclei
Physics potential
CC event rate
e.g 71Ga(ne, e－)71Ge
At neutrino flux: ~1012cm-2s-1 ;
10 tons target materials in nature;
target materials
isotope
Natural Abundance
（％）
Number of target nuclei
(1027)
X(ne, e－)Y
Event rate
（counts/day）
Gallium
71Ga
39.89
33.7 34
Indium
115In
95.7
49.9
208
Ytterbium
176Yb
12.7
4.3
664
Molybdenum
100Mo
9.63
5.8
36.4
Applications (under studies) :
s(nNCC) measurements; solar-n detector calibration ; oscillation studies … e.g. q13 (?)

22. To complete list Get more correct U-238 production rate  0.6;
Get correct relative U-238 fission rate  ~5%
Goal: accuracy- 20~30% natural core ; 5-10% loaded core ;
Complete radiative decay analysis;
Select the loaded candidate isotope with best FOM.
Study potential neutrino physics applications.

23. Conclusion
Power plant can emit electron neutrino, we perform the M-C simulation for the neutrino flux；
The simulation result has been applied for TEXONO experiment data analysis to deduce the limits of magnetic moment and radiative decay lifetime of electron neutrino;
The physics potential of the reactor neutrino experiment has been discussed.

24. Thanks !