1. 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

2. 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

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

4. 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 　 　 　 　　104 　　 m
2019/8/21
2nd Open Meeting for the Hyper-Kamiokande Project

5. 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

6. 2nd Open Meeting for the Hyper-Kamiokande Project
Oscillation
Absorption
2019/8/21
2nd Open Meeting for the Hyper-Kamiokande Project

7. 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

8. 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 ~
Density ~ 2.3
Density is less important !
What we really want to know is :
2019/8/21
2nd Open Meeting for the Hyper-Kamiokande Project

9. 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

10. 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

11. 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

12. 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

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

14. 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

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

16. 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

17. 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

18. 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

19. 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

20. 2nd Open Meeting for the Hyper-Kamiokande Project
Even if I’m alien…
2019/8/21
2nd Open Meeting for the Hyper-Kamiokande Project