Neutrinographic imaging of the earth A. Taketa, H. K. M Tanaka ERI, University of Tokyo CHEER, Earthquake Research Institute Center for High Energy gEophysics Resarch 2019/8/21 2nd Open Meeting for the Hyper-Kamiokande Project

2nd Open Meeting for the Hyper-Kamiokande Project Table of Contents Introduction Geophysics potential of neutrino Geophysics potential of Hyper-K Summary and future prospect Introduction Geophysics potential of neutrinography Geophysics potential of Hyper-K Summary and future prospect 2019/8/21 2nd Open Meeting for the Hyper-Kamiokande Project

What is radiographic imaging? Detector Target Inversion Penetrative particles (X-rays, muons, Neutrinos) Image

2nd Open Meeting for the Hyper-Kamiokande Project Radiographies There are missing ranges! Photon(X-ray) muon neutrino Photography Muography Neutrinography Air shower (Electro- magnetic component) The holy grail of geophysics Polarization EM field Spin Magnetism Oscillation 0.1 　 1 10 102　 　 103 　　104 　　 105 106 m 2019/8/21 2nd Open Meeting for the Hyper-Kamiokande Project

Absorption V.S. Oscillation E > ~TeV E < 30GeV Sensitive to the density of nucleus (mass density) Sensitive to the density of electrons a Giga ton detector Mega ton detector Still not enough Enough? The earth is too small to radiograph 2019/8/21 2nd Open Meeting for the Hyper-Kamiokande Project

2nd Open Meeting for the Hyper-Kamiokande Project Oscillation Absorption 2019/8/21 2nd Open Meeting for the Hyper-Kamiokande Project

2nd Open Meeting for the Hyper-Kamiokande Project Table of Contents Introduction Geophysics potential of neutrinography Geophysics potential of Hyper-K Summary and future prospect 2019/8/21 2nd Open Meeting for the Hyper-Kamiokande Project

2nd Open Meeting for the Hyper-Kamiokande Project What can we dream of ? Only neutrino can tell us the core / mantle density (deeper than 5km). PREM(1981) is good enough, unfortunately Boundary ~ 10km @maximum Density ~ 2.3 g/cc @maximum Density is less important ! What we really want to know is : 2019/8/21 2nd Open Meeting for the Hyper-Kamiokande Project

2nd Open Meeting for the Hyper-Kamiokande Project The biggest question What is the geomagnetic field ? Who order it ? W. Gilbert 1600, A. Einstein 1905 If we believe PREM density and have enough statistics of atm-ν Oscillation based radiography is sensitive to electron density. We will be able to get A/Z and to start chemical composition study of earth core !! 2019/8/21 2nd Open Meeting for the Hyper-Kamiokande Project

2nd Open Meeting for the Hyper-Kamiokande Project Why A/Z is important ? Phase transition on boundary Dynamo theory requires convection Inner core : Fe rich Outer core: 90wt% Fe + 10wt% light (A/Z)Fe /(A/Z)light -1=8% But … (A/Z)inner / (A/Z)outer -1 = 1% 2019/8/21 2nd Open Meeting for the Hyper-Kamiokande Project

To make the dream come true Precise measurement of neutrino mixing parameters ! Giga ton detector for 1GeV – 30GeV ? Discouraged? Only neutrino can do it !! 2019/8/21 2nd Open Meeting for the Hyper-Kamiokande Project

2nd Open Meeting for the Hyper-Kamiokande Project Table of Contents Introduction Geophysics potential of neutrinograhy Geophysics potential of Hyper-K Summary and future prospect 2019/8/21 2nd Open Meeting for the Hyper-Kamiokande Project

HK can distinguish vacuum and matter ~100 events cosΘ Log10(E[GeV]) 2019/8/21 2nd Open Meeting for the Hyper-Kamiokande Project

2nd Open Meeting for the Hyper-Kamiokande Project Table of Contents Introduction Geophysics potential of neutrinograhy Geophysics potential of Hyper-K Summary and future prospect 2019/8/21 2nd Open Meeting for the Hyper-Kamiokande Project

What I can do for HK WG as a experimental physicist 2019/8/21 2nd Open Meeting for the Hyper-Kamiokande Project

2nd Open Meeting for the Hyper-Kamiokande Project My duty in ERI (2013) Muon radiography of active seismic fault from underground. Observe Atotsugawa seismic fault from bore hole (drilled on 2003, 15cm diameter, 350m depth ). Underground obs. with PMT and elec. Measure the direction and inclination for seismic intensity calc. Inotani St. Kamioka office Bore hole 2019/8/21 2nd Open Meeting for the Hyper-Kamiokande Project

What I can (want to) do for HK WG as a experimental physicist PMT evaluation and calibration Photo-sensor WG Water proof detector (electronics) DAQ WG We can provide test bench in deep water At Kamioka (15cm diameter, 350m depth) and Univ. of Tokyo (30cm diameter, 80m depth) I was Ph.D student of ICRR until 3 years ago (not atm-ν but Highest-E CR) 2019/8/21 2nd Open Meeting for the Hyper-Kamiokande Project

2nd Open Meeting for the Hyper-Kamiokande Project Request Simulation tool for atm-ν oscillation Database of detector parameters Not immediately Including reconstruction performances 2019/8/21 2nd Open Meeting for the Hyper-Kamiokande Project

2nd Open Meeting for the Hyper-Kamiokande Project Conclusion Muon discovery : 1936 Muography : 1990s Air shower discovery : 1938 AS radiography : 2011 Neutrino discovery : 1950s Neutrinography : 2010s-2020s 2019/8/21 2nd Open Meeting for the Hyper-Kamiokande Project

2nd Open Meeting for the Hyper-Kamiokande Project Even if I’m alien… 2019/8/21 2nd Open Meeting for the Hyper-Kamiokande Project