A brief overview of the 8th Annual Applied An4neutrino Physics Workshop – and next
steps
University of Hawaii, Manoa East-‐West Center October 5 2012
Principles of detec4on Work horse -‐ Inverse Beta Decay this community’s proper focus
Dark Horse – coherent sca5er detec7on may lead to 10-‐100-‐fold reduc4on in detector size Slight problem: it has never been measured aOer 30 years of fiRul aSempts by many people numerous groups now pursuing this
Very Dark Horse – Inverse Beta Decay on 3He Nubar + 3He à e+ + tri4um
Dealing with the IAEA
• We now have a formal IAEA statement of interest in select topics
• And an informal mechanism for interac4ng with IAEA (the Ad Hoc Working group)
• Technologies: Above-‐ground detec4on, improved spectra, ease of deployment – all being pursued by groups worldwide
• Missions: Plutonium disposi4on, shipper-‐receiver difference, long range monitoring
How do the latest reactor experiments affect an4neutrino-‐based nonprolifera4on ?
Now: Theta-‐13 experiments have this year provided us with the most precisely measured mixing angle, and:
ü improved nonprolifera4on monitoring technology, precise measurements of reactor spectra, and improved predic4ons of spectra
Next: The reactor anomaly (and other evidence) allow for a new sterile neutrino leading to: ü improved nonprolifera4on monitoring technology, precise measurements of reactor spectra, and possibly improved predic4ons of spectra
θ13 = 8.9°± 0.9°
Many experimental efforts explicitly devoted to nonprolifera4on are making steady progress ..
Segmented detectors: CORMORAD, PANDA, US Li detector, T2K-‐like elements
Helps reduce shielding (dominates system size) Helps reduce overburden (increases flexibilty of deployment) Some results so far from deployed detectors • Segmenta4on does appear to improve background
rejec4on – all deployed experiments • But the signal efficiency may be too low (US jury is s4ll out)
• Reactor-‐related backgrounds are a significant concern depending on the configura4on (CORMORAD experience) -‐ and some mysteries about the precise source of these
• More recently: use T2K plas4c cells to create a segmented array work ongoing, ques4ons about light collec4on efficiency
Plastic scintillator read out by Y-11 fibre
Homogenous detectors and demonstra4ons in countries under safeguards
• NUCIFER – below-‐ground, well engineered detector in a high background environment – first data taken this year
• KASKA – above-‐ground – several innova4ons
– PSD in buffer, PSD in shield, first demo against a research reactor (140 MWt) – Current signal/background is 1/45 – beSer
shield and bg rejec4on in a proposed itera4on
• CANDU (US-‐Canada) -‐ below-‐ground, evolu4onary from SONGS, first
demo against a CANDU
All near-‐field technology developments -‐
Community has heeded IAEA 2008 expressions of technology interest Each itera4on has brought improvement in the signal to background – Some deployments indicate the need for modest shielding for above-‐ground deployments
– We s7ll await defini7ve evidence for unshielded or above-‐ground detec7on (2013 ?)
Direc4onality using inverse beta
The neutron carries the momentum informa7on But the emi5ed neutron energy is low 10-‐100 keV and hard to measure Best bet so far: look at the net displacement of the neutron with respect to the Positron posi7on Chooz has done this and reconstructed the angle of incident an7enutrinos to ~20 degrees (1 sigma) Recently – new a5empt to measure direc7onality in the Double Chooz experiment – Erica Caden talk 6 degree reconstructed half-‐aperture cone
Direc7onality has considerable interest for nonprolifera7on – hidden reactors, ranging, tracking mul7ple reactors
The mini-‐Time Cube – fine segmented design with 10-‐100 ps 4ming
• Goal: precise reconstruc4on of par4cle trajectories/direc4ons using 4ming
• detailed simula4ons show the power of 4ming reconstruc4on once the detector is fully instrumented
-‐ Takes advantage of ongoing PMT and electronics R&D -‐ Gemng the neutron first or early scaSer is s4ll a problem (for everyone) -‐ Scalability to very large sizes would be challenging
Modeling the poten4al of big detectors
• What can big detectors do ? SNIF and UH/IHI/NGA studies -‐ mul4ple 150 kT scale detectors can triangulate to hidden 100-‐300 MWt reactors at ~200 km standoff
• Good treatment of backgrounds – extrapolated from KL/Borexino
• Only Liquid Scin4llator detectors modeled so far
• Challenge to modelers – what does it take to exclude the existence of 10-‐50 MWt reactors ?
• 10 MWt is a natural target à 3 kg of Pu per year
WATCHMAN: Use a gadolinium-‐doped water detector to detect an4neutrinos at ~ 1 kilometer standoff from a 100 MWt US research reactor , or further from a GWt reactor
Poten4al big detectors
12
Kiloton scale detector
Research or power reactor // 0.1 -‐ 10 km standoff
30-‐200 meters overburden
Key point of this demonstra4on: We consider Gd water the most straighRorward path to the largest scale detectors that are needed for true remote monitoring
Japan has plans to build a big water based detector – will it be sensi4ve to an4neutrinos ?
-‐ HyperKamiokande • 560,000 ton mul4purpose water detector
being planned by Japan • Time scale: ~12 years • Interest in U.S. science community in
par4cipa4on will lead to further R&D in this area
• Gd an op4on but not guaranteed
WATCHMAN demonstra4on would give strong confidence for exercising the Gd op4on Geoan4neutrino science is a poten4al ally
EGADS-‐ 200 ton deeply buried detector to evaluate Gd-‐doped an4neutrino detec4on
• backgrounds • materials • energy thresholds
This detector volume is too small for direct demonstra4on of sensi4vity
New Materials (Minfang Yeh) • Gd-‐LAB a high quality baseline scin4llator
now demonstrated in RENO and Daya Bay -‐ 10,000 photons/MeV, high flashpoint, dopable
• Water based liquid scin4llator – improve light output rela4ve to water Cerenkov – must have a Gd dopant for big an4neutrino detectors
• Near term studies of water based liquid scin4llator by UH student Josh Murillo to directly measure gamma-‐ray spectra
• For the biggest detectors, circula4on and purifica4on in the presence of the Gd-‐scin4llator remains to be solved..
Rate based measurements provide informa4on about fissile content – in conjunc4on with extra
informa4on
Need either: • the thermal power • Or, a previous cycle that you trust
• Or a rela4ve measurement that may weaken but does not remove sensi4vity to changes in fissile content
Anna Hayes simula4on
Spectral analyses and improved simula7ons can help reduce dependence on operator in making es7mates of reactor Pu
content
Ongoing efforts in the US and Japan at using state of the art codes for safeguards es7mates IAEA wants this whether an7neutrino detectors are involved or not
Spectroscopy – David, Patrick, Anna Many compe4ng correc4ons to the predicted
an4neutrino spectrum
• Finite size of the decaying neutron • Atomic electron screening (small) • Finite size of nuclear charge • QED correc4ons • Weak magne4sm – forbidden transi4ons make a big contribu4on to total
spectrum, and are not well characterized
• New spectral predic4on shows an increase rela4ve to previously predicted spectrum (Schreckenbach) – rough agreement in new predic4on between Huber and Mueller/Lhuillier/Lasserre … and Hayes
• Anna: the overall complexity of the errors make you wonder if some error contribu4on has been missed or mishandled
ILL inversion
simple !"shape
our result1101.2663
2 3 4 5 6 7 8"0.05
0.00
0.05
0.10
0.15
E# !MeV"
#$"$
ILL$%$
ILL
How does this affect applied an4neutrino physics ? • Uncertain4es in predicted/
measured spectra have a big impact on the search for neutrino oscilla4ons – and connect to problems in other experiments (Chris4na’s talk)
• They have a more modest impact on our ability to extract informa4on on plutonium content in the core – (70-‐100 kg sensi4vity à 50-‐25 kg sensi4vity) – and we may be able to use a high sta4s4cs measurement at a par4cular reactor as a template, with no predic4on
• The have no impact on the poten4al for remote monitoring and discovery/exclusion of distant reactors
Correla4ons between errors among fissioning isotopes tend to reduce their influence on fissile mass es4ma4on Even current spectroscopic capability is beneficial in reducing dependence on operator inputs
Overall
• It’s exci4ng to see a this new discipline con4nue to mature – Applied An4neutrino Physics
• Historical and con4nued excellent connec4ons to world-‐class physics experiments
• Progress con4nues, but will be slow, toward gemng an4neutrino detectors used for nonprolifera4on
• Con4nued coordina4on among researchers can help make this adop4on happen sooner
Where to next ?
Canada, AECL host -‐ Pt Lepreau deployment -‐ Country under safeguards -‐ Strong local interest and neutrino physics community
India INO experiment A great place for a nonprolifera4on workshop
China New underground lab, Daya Bay expt. A great place for a nonprolifera4on workshop
Chile ANDES underground lab A great place for a nonprolifera4on workshop