1. M-C simulation of reactor e flux;
STUDIES OF REACTOR ELECTRON NEUTRINO MAGNETIC MOMENT AND RADIATIVE DECAY
M-C simulation of reactor e flux;
Data analysis for the limits of electron neutrino magnetic moment ;
Data analysis for the limit of neutrino 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 新竹

2. M-C simulation of reactor e flux
Theory calculation
Experiment Measurement
Magnetic moment
Radiative decay
M-C simulation
Experiment Measurement
Magnetic moment
Radiative decay

3. 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

4. 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

5. 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

6. 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 ?

7. 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

8. 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;

9. 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

10. RC 4967tons、stainless steel 1040tons、Zr-alloy 63 tons
M-C simulation of reactor electron
neutrino ——geometry description
RC 4967tons、stainless steel 1040tons、Zr-alloy 63 tons
50Cr %;
54Fe --4.2%;
58Ni --6.3%;
112Sn --0%.
50Cr %;
54Fe --0.1%;
58Ni %;
112Sn --0%.
50Cr %;
54Fe –0.006%;
58Ni %;
112Sn –0.01%.

11. M-C simulation of reactor electron neutrino ——neutron transport
Source neutron sampling
Watt fission spectrum ：
Fired by thermal neutron :
a＝0.988
b＝2.249
Simulation of neutron flux
Tallies

12. Simulation result
Fission neutrons are mostly absorbed by fuel rods and control rods;
Electron neutrino are mainly contributed by Cr-50 in control rods;

13. n-absorption: Thermal neutron capture cross-section
94% of the captured neutrons are thermal neutrons.
Simulation result
n-absorption: Thermal neutron capture cross-section

14. Simulation result
Neutrino flux at detector position due to Cr-50 is: 5.0×108 cm-2s-1
Cross check——
K-eff calculation;
Uncertainty:
The SD of M-C simulation <0.1%;
System error < 15%;

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

16. Data analysis——magnetic moment
Nsm(E)和Nmm(E) A0 a) t2 t3 t4 t1 t0
Reactor on
Aoff
Aon
Reactor off b)
Time
Flux
Average flux
t0： 2001年9月8日；
t1： 2001年10月8日；
t2： 2001年11月14日；
t3： 2001年12月18日；
t4： 2002年1月15日；

17. Data analysis----neutrino magnetic moment
Nsm(E) and Nmm(E)
Flux of e ：
flux：
5.0×108cm-2s-1
Energy ：
747keV
detector：
material：HPGe
Mass ：1.054kg

18. Data analysis——programNo
Yes
date.rz
Standard cut (PSD, cosmic-veto, anticompton)
Energy calibration
Single spectrum Ni(E)
Next spectrum？
Read the next *.rz file
Spectrum adding ΣNi(E)
Read the real measurement time Ti
Dead time correction (ai)、random correction (bi, ci)
Spectrum normalization
n(E)=ΣNi(E)/ ΣTiai bici
The end
Data analysis——program

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

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

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

22. Data analysis ——neutrino decay
Energy range：0～6MeV

23. Data analysis—— neutrino decay
Non(E)－Nbkg(E)

24. Data analysis—— neutrino decay
h＝－0.055±0.061
t/mn≥1.3 s·eV－1 (C.L. 68%)

25. 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 …

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

27. Number of target nuclei
Physics potential
71Ga(ne, e－)71Ge
CC event rate
target materials
isotope
Nature enrichment
（％）
Number of target nuclei
(1027)
X(ne, e－)Y
Event rate
（counts/day）
Gallium
71Ga
39.89
33.7
3.4
Indian
115In
95.7
49.9
20.8
Ytterbium
176Yb
12.7
4.3
6.64
Molybdenum
100Mo
9.63
5.8
3.64
Neutrino flux: 2×1011cm-2s-1 ;
10 tons target materials in nature;

28. Conclusion
We performed the simulation of the emissions of electron neutrinos from a nuclear reactor. At detector position, the electron neutrino flux due to 51Cr is : 5.0×108cm2s-1；
The limits of electron neutrino magnetic moment and radiative decay lifetime has been found based on a reactor neutrino experiment ：
The physics potential of the reactor neutrino experiment has been discussed.
t/mn≥1.3 s·eV－1 (C.L. 68%)

29. Thanks !