1. John Learned Univ. of Hawaii
Future Large Liquid Scintillator Experiments
For Geonu Studies and Much More
John Learned
Univ. of Hawaii
Presentation at Neutrino Geosciences,
Takayama, 23 March 2013
23 March 2013
JGL at Geonu 2013

2. John Learned at Cornell
Where do Neutrinos come from? We can study most of these with a deep ocean instrument!
Nuclear Reactors
(power stations, ships) 
Sun 
Particle Accelerator 
Supernovae
(star collapse)
SN 1987A 
Earth’s Atmosphere
(Cosmic Rays) 
Astrophysical
Accelerators
Soon ? 
Big Bang
(here 330 /cm3)
Indirect Evidence
Earth’s Composition
(Natural
Radioactivity)
13 April 2009
John Learned at Cornell

3. Why this is a wide interest project
A large deep underwater detector can address almost all of these neutrino sources! Many of them simultaneously. Low and high energy searches do not interfere. Nor do searches for rare phenomena such as supernovae and proton decay. Such an instrument is not just one experiment yielding one number, but will supply a huge variety of results (and PhDs) and can engage a large scientific community. This is true in geology as well as particle physics and astrophysics
23 March 2013
JGL at Geonu 2013

4. Geology Involvement
Studies to decide on locations for detector: Ocean bottom cores, region studies Development of pile and other models Best possible regional calculations Studies on spectra expected: Close examination of U/Th decay chains and beta decays Pressure effects? Improvement of earth models: Tuning various models with working groups Crucial temperature and seismic studies in less know regions? Sharpening community focus on earth heat issues Engaging the whole Geo Community in a project touching many specialities Seeking lateral variation and possible explanations, hidden reservoirs We need a large multidisciplinary team to put this all together, not just physicists.
23 March 2013
JGL at Geonu 2013

5. The Road to Geonu Science
Know we need great mass detectors > kiloton scale -> megaton scale
Only (presently) viable technology is large tanks of liquid scintillator
Difficult to resolve mantle from crust at continental locations
Best to be far from nuclear reactors = mid-ocean
Need to be deep to avoid background (>3km)
Ocean offers potential for relocation to multiple sites
We can start with what we have now, all technology exists
Challenges to do even better and go further than just “local” geonu rate:
Better scintillator (output, water based, attenuation length)
New optical detectors, better coverage and time resolution
Directionality?
K40 nus from the earth?
23 March 2013
JGL at Geonu 2013

6. Large Electron Anti-Neutrino Experiments*
Continuing Experiments KamLAND 1 kT LS 2 kmwe 1 MeV Borexino 0.4 kT LS 3 kmwe 1 MeV Near Term SNO+ 1kT LS+ 4 kmwe 1 MeV SK (w/Gd?) 22kT H2O+Gd 2 kmwe 4 MeV Proposed HyperK 600kT H2O+? 1.5 kmwe(?) 6 MeV DayaBay2 20kT LS 1.5 kmwe 1 MeV RENO50 5kT LS ? kmwe 1 MeV LENA 50kT LS 3 kmwe 1 MeV LBNE Homestake 17kT Lar 0 or 4 kmwe 100 MeV? Watchman 1kT H2O+Gd 0.3 kmwe 4 MeV Hanohano 10kT LS 2-5 kmwe 1 MeV
*Neglecting MINOS and NOVA, INO and MiniBOONE detectors, not relevant to this discussion on MeV electron anti-neutrinos.
(And also to keep the list manageable… herein.)
23 March 2013
JGL at Geonu 2013

7. Rough Physics Domains of Large Nuebar ExperimentsKL BX
SNO+
SK w/ HK
DB2
RN50
LENA
Hstk LAr*
Watch
Hano
Reactor Mon ☻☻ ☻
☻☻☻
Reactor Hierarchy
Geonu Det.
Geonu Mantle CR
nus
Indirect DM SN
Relic SN
No Nu ββ
LBNE
θ13 ☻?
CPV
PDK
* Assuming 37 kT and deep
23 March 2013
JGL at Geonu 2013

8. Locations for Present & Possible Geonu Experiments
SNO+
LENA
Baksan
LBNE LAr
Hanohano
Kamland
SuperK
HyperK
DayaBay2
EARTH ?
Borexino
Color indicates U/Th neutrino flux, mostly from crust
13 April 2009
John Learned at Cornell

9. Simulated Geoneutrino Origination Points
50% within 500km 25% from Mantle
KamLAND
In Mid-Ocean
70% Mantle
30% Other
Assumes
homogeneous
mantle &
no core source
Sanshiro Enomoto
13 April 2009
John Learned at Cornell

10. John Learned at Cornell
Why we need Geonu measuements in the deep ocean to measure the Mantle Contribution
Crust Only
Mantle
Models
16-18 typical
12-39 extreme
mantle
Steve Dye
13 April 2009
John Learned at Cornell

11. John Learned at Cornell
With a deep ocean detector we could resolve a Single Reactor Source at CMB
resolution to few km
10 sample simulated 1 yr runs
1 GW source observed by 100 kT detector
can be cleaned up
13 April 2009
John Learned at Cornell

12. John Learned at Cornell
What Next for Geonus?
Measure gross fluxes from crust and mantle
Discover or set limits on georeactors.
Better earth models
Explore lateral homogeneity
Use directionality for earth neutrino tomography
Follow the science….
13 April 2009
John Learned at Cornell

13. JGL at Geonu 2013
23 March 2013
Applied Neutrinos! Program to Study Long Range Reactor Monitoring and Detection
Working with colleagues at UH, NGA and IAI in US.
Studies using all available neutrino tools:
Hypothetical large detectors (100kT class)
Assume availability of new photodetectors (LAPPDS of the like)
Use oscillations fully in analysis
Calculate full backgrounds including earth model and detector depth
Use full Max Liklihood, with Bayesian statistics
Test importance of directional detection (obvious answer: very big boost)
Conclusions: Works better than we had guessed… big paper in press in Physics Reports. Will show some pictures here.

14. First, testing out new technology for precise antineutrino detection at UH
mTC Idea
Do imaging with (100 ps) fast timing, not optics (time reversal imaging).
Small portable 2.2 liter scintillating cube,
Boron doped plastic.
4 x 6 MCP (x64 pixels each) fast pixel detectors on surrounding faces
Get neutrino directionality.
Reject noise on the fly.
~10/day anti-neutrino interactions (inverse beta decay signature) from power reactor (San Onofre).
13 cm
2.2 liter
23 March 2013
JGL at Geonu 2013

15. mTC Virtues Small size avoids positron annihilation gammas which
smear resolution (Xo ~42 cm).... gammas mostly escape,
permitting precise positron creation point location.
Fast pixel timing (<100ps) and fast pipeline processing of
waveforms rejects background in real time.
Having many pixels plus use of first-in light permits mm precision in vertex locations.
Neutrino directionality via precision positron production
and neutron absorption locations.
No need for shielding (unlike other detectors,
except very close to reactor
Feasible even in high noise environment, near reactor
vessel, at surface (eg. in a truck).
Plan to take to reactor summer 2013
23 March 2013
JGL at Geonu 2013

16. Snapshot of the Fermat Surface for a Single Muon-likeTrack
Huygens
wavelets
Incoherent sum
coincident with
Cherenkov surface:
Not polarized!
J. Learned arXiv: v1
23 March 2013
JGL at Geonu 2013

17. Time Reversal Image Reconstruction
23 March 2013
JGL at Geonu 2013
Figure by Mich Sakai

18. 23 March 2013
JGL at Geonu 2013

19. 23 March 2013
JGL at Geonu 2013

20. Fitting the Positron Streak
23 March 2013
JGL at Geonu 2013

21. 23 March 2013
JGL at Geonu 2013

22. Reactor Rate versus Range
66 kT water based
detector, no cuts.
300 MWth Reactor
23 March 2013
JGL at Geonu 2013

23. Where the Reactors Live
23 March 2013
JGL at Geonu 2013

24. Table of Backgrounds & Rates
23 March 2013
JGL at Geonu 2013
Lasserre and friends

25. Smart integration of geonus illustration
23 March 2013
JGL at Geonu 2013

26. Crust and Mantle versus Range
23 March 2013
JGL at Geonu 2013

27. Where Comes the Geonus? Account for oscillations and energy smearing
One lesson of the study: oscillations are very important tool.
NUDAR
23 March 2013
JGL at Geonu 2013

28. Geonu and Reactor Spectra location off Spain ~300km to nearest reactor
Geonus rule!
23 March 2013
JGL at Geonu 2013

29. Seeking a Reactor: Where Comes the Background?
Sum of backgrounds
Spectrum of backgrounds
23 March 2013
JGL at Geonu 2013

30. 23 March 2013
JGL at Geonu 2013

31. Finding a Reactor and Power Output
23 March 2013
JGL at Geonu 2013

32. Future Geonu Dreams: Directional Sensitivity
Directional information provides:
・Rejection of backgrounds
・Separation of crust and mantle
・Earth tomography by multiple detectors
Good News:
・Recoiled neutron remembers direction
Bad News:
・Thermalization blurs the info
・Gamma diffusion spoils the info
・Reconstruction resolution is too poor
Wish List:
・large neutron capture cross-section
・(heavy) charged particle emission &
・good resolution detector (~1cm)
13 April 2009
John Learned at Cornell

33. Increased angular resolution buys a lot
23 March 2013
JGL at Geonu 2013

34. Hanohano a mobile deep ocean detector
Measure electron antinus for:
Geophysics
Particle physics (hierarchy,
mixing parameters)
Remote reactor monitoring for anti-proliferation.
And lots more science…
Results from DARPA funded study, employing
Makai Ocean Engineering for preliminary design
and feasibility study.
10 kiloton liquid scintillation
Up to ~100 kt possible
Deploy and retrieve from barge
13 April 2009
John Learned at Cornell

35. Hanohano Engineering Studies Makai Ocean Engineering
Studied vessel design up to 100 kilotons, based upon cost, stability, and construction ease.
Construct in shipyard
Fill/test in port
Tow to site, can traverse Panama Canal
Deploy ~4-5 km depth
Recover, repair or relocate, and redeploy
Barge 112 m long x 23.3 wide
Deployment Sketch
Descent/ascent 39 min
13 April 2009
John Learned at Cornell

36. Addressing Technology Issues
Scintillating oil studies in lab
P=450 atm, T=0°C
Testing PC, PXE, LAB and dodecane
No problems so far, LAB favorite… optimization needed
Implosion studies
Design with energy absorption
Computer modeling & at sea
No stoppers
Power and comm, no problems
Optical detector, prototypes OK
Need second round design
20m x 35m
fiducial vol.
1 m oil
2m pure water
13 April 2009
John Learned at Cornell

37. 2 Candidate Off-shore Nuclear Power Reactor Sites for Physics
San Onofre, California- ~6 GWth
Maanshan, Taiwan- ~5 GWth
Can do unique studies of neutrino properties km out from reactors.
13 April 2009
John Learned at Cornell

38. Summary of Expected Results Hanohano- 10 kt-1 yr Exposure
Neutrino Geophysics- near Hawaii
Mantle flux U geoneutrinos to ~10%
Heat flux ~15%
Measure Th/U ratio to ~20%
Rule out geo-reactor if P>0.3 TW
Neutrino Oscillation Physics- ~55 km from reactor
Measure sin2 (θ12) to few % w/ standard ½-cycle
Measure sin2(2θ13) down to ~0.05 w/ multi-cycle
Δm231 to less than 1% w/ multi-cycle
Mass hierarchy w/multi-cycle & no near detector; insensitive to background, systematic errors; complementary to Minos, Nova
Much other astrophysics and nucleon decay too….
13 April 2009
John Learned at Cornell

39. John Learned at Cornell
Additional Physics/Astrophysics Hanohano will be biggest low energy neutrino detector (except for maybe LENA)
Supernova Detection: special νe ability
Relic SN Neutrinos
GRBs and other rare impulsive sources
Exotic objects (monopoles, quark nuggets, etc.)
Long list of ancillary, non-interfering science, with strong discovery potential
Broad gauge science and technology, a program not just a single experiment.
13 April 2009
John Learned at Cornell

40. Other Applications for a large deep-water neutrino detector
Long Baseline with accelerators ~ 1 GeV
Hanohano with Tokai Beam (between Japan and Korea)?
LENA with CERN beam??
New LBNE Experiment with Fermilab Beam??
Nucleon Decay (high free proton content)
view details of decays such as Kaon modes
Particle Astrophysics (low mass WIMPS,…)
+ All the low energy physics (geonus, reactor studies, monitoring, solar neutrinos…..) unimpeded!
23 March 2013
JGL at Geonu 2013

41. JGL at Geonu 2013
23 March 2013
What now?
We are ready to plan for a large deep ocean neutrino detector
To study geology
And much else
We need a large interdisciplinary and multinational team to pull this off
Many areas of expertise needed
Please consider how you can help