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

We can study most of these with a deep ocean instrument!

Nuclear Reactors
(power stations, ships)
Sun


Particle Accelerator

Earth’s Atmosphere
(Cosmic Rays)

Earth’s Composition
(Natural
Radioactivity)
13 April 2009 John Learned at Cornell
Supernovae
(star collapse)
SN 1987A

Astrophysical
Accelerators
Soon ?
Big Bang
(here 330

/cm 3 )
Indirect Evidence
2

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 3

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 4

23 March 2013
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?
JGL at Geonu 2013 5

Large Electron Anti-Neutrino Experiments*
Continuing Experiments
KamLAND 1 kT LS 2 kmwe 1 MeV
1 MeV Borexino
Near Term
SNO+
SK (w/Gd?)
Proposed
HyperK
0.4 kT LS
1kT LS+
22kT
3 kmwe
4 kmwe
H2O+Gd 2 kmwe
600kT H2O+?
1.5 kmwe(?)
DayaBay2
RENO50
20kT LS
5kT LS
LENA 50kT LS
LBNE Homestake 17kT Lar
Watchman
Hanohano
1.5 kmwe
? kmwe
3 kmwe
0 or 4 kmwe
1kT H2O+Gd 0.3 kmwe
10kT LS 2-5 kmwe
1 MeV
4 MeV
6 MeV
1 MeV
1 MeV
1 MeV
100 MeV?
4 MeV
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 6

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

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
John Learned at Cornell 13 April 2009 8

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

13 April 2009
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 10 John Learned at Cornell

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

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 12

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.
13

23 March 2013
First, testing out new technology for precise antineutrino detection at UH
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).
2.2 liter
JGL at Geonu 2013 14

• Small size avoids positron annihilation gammas which smear resolution (X o
~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 15

23 March 2013
Snapshot of the Fermat Surface for a Single Muon-likeTrack
Track
Huygens wavelets
JGL at Geonu 2013
Incoherent sum coincident with
Cherenkov surface:
Not polarized!
J. Learned arXiv:0902.4009v1
16

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

23 March 2013 JGL at Geonu 2013 18

23 March 2013 JGL at Geonu 2013 19

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

23 March 2013 JGL at Geonu 2013 21

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

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

23 March 2013 JGL at Geonu 2013
Lasserre and friends
24

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

23 March 2013 JGL at Geonu 2013 26

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 27

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

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

23 March 2013 JGL at Geonu 2013 30

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

13 April 2009
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)
John Learned at Cornell 32

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

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

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
13 April 2009
Descent/ascent 39 min
John Learned at Cornell 35

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
Implosion signals from empty sphere and a sphere with 30% volume filled with foam
1
0.8
0.6
0.4
0.2
0
-0.4
-0.6
-0.8
-1
0.0035
0.0045
0.0055
0.0065
0.0075
0.0085
0.0095
30% Foam filled (4105m)
Empty (4280m)
Time (seconds)
John Learned at Cornell 13 April 2009
20m x 35m fiducial vol.
1 m oil
2m pure water
36

2 Candidate
Off-shore Nuclear
Power Reactor Sites for Physics
San Onofre, California- ~6 GW th
Maanshan, Taiwan- ~5 GW th
13 April 2009
Can do unique studies of neutrino properties 50-60 km out from reactors.
John Learned at Cornell 37

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 sin 2 (θ
12
) to few % w/ standard ½-cycle
Measure sin 2 (2θ
13
) down to ~ 0.05 w/ multi-cycle
Δm 2
31 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 38

Additional Physics/Astrophysics
Hanohano will be biggest low energy neutrino detector (except for maybe LENA)
Supernova Detection: special ν e 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 39

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 40

What now?
JGL at Geonu 2013 23 March 2013
 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
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