ppt

Report
23 March 2013
Future Large Liquid Scintillator Experiments
For Geonu Studies and Much More
John Learned
Univ. of Hawaii
Presentation at Neutrino Geosciences,
Takayama, 23 March 2013
JGL at Geonu 2013
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Where do Neutrinos come from?
We can study most of these with a deep ocean instrument!

Nuclear Reactors
(power stations, ships)


Particle Accelerator

Supernovae
(star collapse)
SN 1987A

Astrophysical
Accelerators
Soon ?
Earth’s Atmosphere
(Cosmic Rays)
Earth’s Composition
13 April 2009
Sun
Big Bang
(here 330 /cm3)
Indirect Evidence
(Natural
Radioactivity)
John Learned at Cornell
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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
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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.
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JGL at Geonu 2013
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23 March 2013
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?
JGL at Geonu 2013
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Large Electron Anti-Neutrino Experiments*
Continuing Experiments
KamLAND
Borexino
1 kT LS
2 kmwe
1 MeV
0.4 kT LS
3 kmwe
1 MeV
4 kmwe
1 MeV
H2O+Gd 2 kmwe
4 MeV
Near Term
SNO+
SK (w/Gd?)
1kT
22kT
LS+
Proposed
HyperK
600kT
H2O+?
1.5 kmwe(?)
6 MeV
DayaBay2
20kT
LS
1.5 kmwe
1 MeV
RENO50
5kT
LS
? kmwe
1 MeV
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
1 MeV
LENA
2-5 kmwe
*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.)
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JGL at Geonu 2013
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Rough Physics Domains of Large Nuebar Experiments
Physics
KL
BX
SNO+
SK w/
HK
DB2
RN50
LENA
Hstk
LAr*
Watch
Hano
Reactor Mon
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Reactor
Hierarchy
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Geonu Det.
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Geonu
Mantle
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CR
nus
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Indirect
DM
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SN
nus
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Relic SN
nus
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No Nu
ββ
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LBNE
θ13
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LBNE
CPV
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PDK
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JGL at Geonu 2013
* Assuming 37 kT and deep
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Locations for Present & Possible Geonu Experiments
SNO+
LENA
Baksan
LBNE LAr
Hanohano
Kamland
SuperK
HyperK
DayaBay2
EARTH ?
13 April 2009
Borexino
Color indicates U/Th neutrino flux, mostly from crust
John Learned at Cornell
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Simulated Geoneutrino Origination Points
KamLAND
In Mid-Ocean
70% Mantle
30% Other
Assumes
homogeneous
mantle &
no core source
13 April 2009
50% within 500km
25% from Mantle
John Learned at Cornell
Sanshiro Enomoto
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Why we need Geonu measuements in the deep ocean to
measure the Mantle Contribution
13 April 2009
Crust Only
Mantle
Models
16-18 typical
12-39 extreme
mantle
John Learned at Cornell
Steve Dye
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With a deep ocean detector we could resolve a
Single Reactor Source at CMB
resolution to few km
13 April 2009
10 sample simulated 1 yr runs
1 GW source observed by 100 kT detector
John Learned at Cornell
can be cleaned up
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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
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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.
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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.
2.2 liter
23 March 2013
~10/day anti-neutrino interactions
(inverse beta decay signature) from
power reactor (San Onofre).
JGL at Geonu 2013
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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
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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
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23 March 2013
Time Reversal Image Reconstruction
JGL at Geonu 2013
Figure by Mich Sakai
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JGL at Geonu 2013
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23 March 2013
Fitting the
Positron Streak
JGL at Geonu 2013
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Reactor Rate versus Range
66 kT water based
detector, no cuts.
300 MWth Reactor
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JGL at Geonu 2013
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Where the Reactors Live
JGL at Geonu 2013
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Table of Backgrounds & Rates
JGL at Geonu 2013
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Smart integration of geonus illustration
JGL at Geonu 2013
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23 March 2013
Crust and Mantle versus Range
JGL at Geonu 2013
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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
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Geonu and Reactor Spectra
location off Spain ~300km to nearest reactor
Geonus rule!
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JGL at Geonu 2013
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Seeking a Reactor:
Where Comes the Background?
Sum of backgrounds
Spectrum of backgrounds
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Finding a Reactor and Power Output
JGL at Geonu 2013
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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
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23 March 2013
Increased angular resolution buys a lot
JGL at Geonu 2013
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Hanohano
a mobile deep ocean detector
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
Remote reactor monitoring for antiproliferation.
Up to ~100 kt possible
And lots more science…
Deploy and retrieve from barge
13 April 2009
John Learned at Cornell
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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
13 April 2009
Barge 112 m long x 23.3 wide
Deployment Sketch
Descent/ascent 39 min
John Learned at Cornell
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Addressing Technology
Issues
Scintillating oil studies in lab
20m x 35m
fiducial vol.
P=450 atm, T=0°C
Testing PC, PXE, LAB and dodecane
No problems so far, LAB favorite…
optimization needed
1 m oil
Implosion studies
Design with energy absorption
2m pure water
Computer modeling & at sea
No stoppers
Power and comm, no problems
Optical detector, prototypes OK
Need second round design
13 April 2009
Implosion signals from empty sphere and a sphere with 30%
volume filled with foam
1
0.8
Pressure (norm)
0.6
0.4
0.2
0
0.0025
-0.2
0.0035
0.0045
0.0055
0.0065
0.0075
0.0085
0.0095
-0.4
-0.6
30% Foam filled (4105m)
Empty (4280m)
-0.8
-1
Time (seconds)
John Learned at Cornell
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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 50-60 km out from reactors.
13 April 2009
John Learned at Cornell
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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
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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
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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
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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
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