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 2004.02 @ 新竹

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

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

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

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

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 ?

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- 51V + νe 55Fe + e- 55Mn + νe 59Ni + e- 59Co + νe 113Sn + e- 113In + νe

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;

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

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 --0.95%; 54Fe --4.2%; 58Ni --6.3%; 112Sn --0%. 50Cr --0.01%; 54Fe --0.1%; 58Ni --0.63%; 112Sn --0%. 50Cr --0.005%; 54Fe –0.006%; 58Ni --0.34%; 112Sn –0.01%.

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

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

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

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%;

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

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；

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

Data analysis——program No 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

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

Data analysis ——fitting of the e

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

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

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

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

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 …

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

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;

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%)

Thanks !