Reactor antineutrinos in the world

1. Neutrino 2012 June 3-9, 2012 Kyoto, Japan Reactor antineutrinos in the world V. Chubakov1, F. Mantovani1, B. Ricci1, J. Esposito2, L. Ludhova3 and S. Zavatarelli4 1Dip. di Fisica, Università degli Studi di Ferrara and INFN-Ferrara, Italy 2INFN, Laboratori Nazionali di Legnaro, Padova, Italy 3INFN- Milano, Italy 4INFN- Genova, Italy o 1 Why reactor antineutrinos ? Nuclear power plants in the world 2 • Total Thermal Power =1023 GW • Reactor antineutrinos are the main source of background in the detection of geo-neutrinos (i.e. anti-ne from 238U and 232Th decay chains, present in the Earth interior) http://pris.iaea.org/public/ Current status 394 333 215 Japan cores switched off • The High Energy Region (HER) has to be controlled by studying the different contributions from the nuclear reactors, if one wants to disentangle Ngeo-n and Nreact in the Low Energy Region (LER) 249; 69% % Total Thermal Power 1.8 3.3 8 En [MeV] 63; 17% 47; 7.7% 18; 2.6% 15; 3.5% 2;< 1 % PWR BWR PHWR GCR LWGR FBR Signal Calculations 3 • Many ingredients: neutrino physics, nuclear physics, reactor properties… 4 Result: a world wide map • Reactor antineutrino events all over the world • Pee= n -oscillation survival probability [2] • s(En )= cross section anti-ne +p -> e+ +n Eth=1.806 MeV[3] • e=100% efficiency • t= 1 year • Np=1032 target protons (»1ktonliquid scintillator) [1 TNU=1 event/ 1032target protons /year] n PHYSICS DETECTO DETECTOR • di =reactor distance • Pi=thermal power • LF= Load Factor [1] • pk= power fraction • Qk =energy released for fission [4] • lk =reactor anti-neutrino spectrum [5] NUCLEAR REACTOR k = 235U, 238U, 239Pu , 241Pu (nuclear fuel) • Total uncertainties on predicted signal is about 5%, coming from n mixing, antin-spectrum, fuelcomposition and thermalpower React. signal and geo neutrino detection 5 • Reactor signal in Low Energy Region, for different sites. 6 Conclusions and perspectives • We calculated reactor anti-ne signal all over the world, by taking into account updated data on nuclear plants, anti-ne spectrum and ne oscillation parameters. • We compare reactor signal with geo-neutrino signal for different places in the world. • Study of time variation of reactor signal is also possible (±10% variation in summer/winter). • Detailed study on the effect of exhausted fuel must be completed (we estimate a 2% increase in the signal). • Frejus requires a detailed knowledge of closeby reactors. • Kamioka is at the moment a very good site. • Hawaii and Curacao are ‘wonderful’ places also for geo-n study. Bibliography: [1] courtesyby J. Mandula ,IAEA, International Atomic Energy Agency 2012. [4] M. Apollonio et al., Eur. Phys. J. C27, 331 (2003) [2]G.L. Fogli et al., Phys. Rev. D 84, 053007 (2011) [5]Th. A Mueller et al., Phys.Rev.C83:054615 (2011) [3]F.Vissani and A. Strumia,Phys.Lett.B564:42-54 (2003) [6]G. Fiorentini et al., Phys.Rept.453:117-172 (2007) R.B.