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 2004.07@ Osaka

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

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 0.00006 0.0095 0.0002 0.064 0.00017 Zr-2 、Zr-4 alloy 44.9 0.00012 0.00004 Water in the reactor core 37.8 0.187 SIMULATION RESULT

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

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

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

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 0.0012; 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.

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

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

Data analysis ——fitting of the e

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

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

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)

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 (?)

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.

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.

Thanks !