7Be solar neutrino observation with KamLAND

The result of 7Be solar neutrino observation with KamLAND was reviewed based on the latest KamLAND publication [A. Gando et al., (KamLAND collaboration), arXiv:1405.6190 (2014)]. Prior to the observation, the 4 orders of reduction of significant background sources against 7Be solar neutrinos; 210Bi, 210Po, (and their mother isotopes), 85Kr and 40K were done by means of fractional distillation and nitrogen purging. Even though the fiducial volume had faced background intrusions due to convection of the liquid scintillator, 165.4 kton⋅days exposure within 616 days livetime leads 7Be solar neutrino rate as 582±90(kton⋅days)−1. With analysis based on a global three flavor neutrino oscillation, 7Be solar neutrino flux is interpreted as (5.82±0.98)×109cm−2s−1, which confirms the consistency to the standard solar model predictions.