Reconstruction Software Update

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Dave Ayres and The NOnA Experiment
Ayres Rocks Argonne 3 September 2008
Gary Feldman
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Not the Usual Fare

• In this talk, I want to talk about things that we
  usually do not spend much time on in a short NOnA
  talk, but things that are critically important to
  the experiment, namely the things that Dave Ayres
  was responsible for.
• I will start with a short introduction for those
  less familiar with NOnA and then get to Daves
  contributions.

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What is NOnA?

• NOnA is a second-generation experiment on the
  NuMI beamline, which is optimized for the
  detection of nm ? ne oscillations.
• The measurement of ne appearance is essential for
  future work in neutrino oscillations since it is
  necessary for determining the mass ordering of
  neutrino states and studying CP violation.
• NOnA will give an order of magnitude improvement
  over MINOS in measurements of ne appearance and
  nm disappearance. It does this by
• having three times the mass of MINOS,
• being sited off the NuMI beam axis to create a
  narrow bandbeam with more flux in the signal
  region and less background,
• and having ten times the longitudinal
  segmentation of MINOS.

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NOnA Site
The Ash River site is the furthest available site
from Fermilab along the NuMI beamline. This
maximizes NOnAs sensitivity to the mass
ordering.
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NOnA Basic Detector Element
Liquid scintillator in a 4 cm wide, 6 cm deep,
15.7 m long, highly reflective PVC cell.
Light is collected in a U-shaped 0.7 mm
wavelength-shifting fiber, both ends of which
terminate in a pixel of a 32-pixel avalanche
photodiode (APD). The APD has peak quantum
efficiency of 85. It will be run at a gain of
100. It must be cooled to -15oC and requires a
very low noise amplifier.
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Far Detector
The cells are made from 32-cell extrusions.
12 extrusion modules make up a plane. The
planes alternate horizontal and vertical.


There are 1003 planes, for a total
mass of 15 kT. There is enough room
in the building
for 18 kT, which can be
built if we can preserve half of our
contingency. The detector
can start taking data as soon as
blocks are filled and the electronics
connected.
An admirer
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Event Quality
Longitudinal sampling is 0.15 X0, which gives
excellent m-e separation.
A 2-GeV muon is 60 planes long.
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ne CC event
?ep?e-p? E?2.5GeV Ee1.9GeV Ep1.1GeV E?0.2GeV
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Background NC event
??N???p?o E?10.6 GeV Ep1.04GeV E?o 1.97GeV
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NOnA Organization
John Cooper, Project Manager Ron Ray, Deputy
Project Manager Nancy Grossman, Associate PM
Far SiteBuilding Steve Dixon
Scintillator StuartMufson
Fiber Carl Bromberg
Extrusions Rich Talaga
Modules Ken Heller
Electronicsand DAQ LeonMualem
Assembly Dave Ayres
Accelerator and Beamline Nancy GrossmanElaine
McCluskey
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NOnA Organization
John Cooper, Project Manager Ron Ray, Deputy
Project Manager Nancy Grossman, Associate PM
Far SiteBuilding Steve Dixon
The buckstops here
Scintillator StuartMufson
Fiber Carl Bromberg
Extrusions Rich Talaga
Modules Ken Heller
Electronicsand DAQ LeonMualem
Assembly Dave Ayres
Accelerator and Beamline Nancy GrossmanElaine
McCluskey
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More than just Assembly

• Assembly was just one part of Daves
  responsibility. There were at least three
  separate responsibilities
• To design and validate a structure that would
  last for twenty years.
• To figure out how to assemble it.
• To verify that everything would fit together.
• When an early review called for a full-time
  integration person in the project office, we
  replied that we did not need that because we had
  Dave Ayres.

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The Crew

• Of course, Dave did not do all of this himself.
  Some of the key people in his crew over the
  last two years were
• Dixon Bogert, Craig Dukes, Don Friend, Mark
  Gebhard, Andrew Godley, Jim Grudzinski, Vic
  Guarino, Doug Jensen, Hans Jostlein, Karen
  Kephart, Ang Lee, Peter Lucas, Pat Lukens, Tony
  Mann, Bill Miller, Jim Musser, Earl Peterson,
  Dave Pushka, Matt Slabaugh, Rich Talaga, Ernie
  Villegas, Ken Wood, and Allen Zhao.

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Structure

• The NOnA far detector is five stories high, same
  width, and 3/4 of a football field long, made
  entirely of plastic extrusions glued together and
  filled with liquid.
• There are no engineering guidelines for such a
  structure.
• The problem with plastic is that it is plastic
  Under the hydrostatic pressure, it swells, and
  over time, it creeps.
• The problem of finding a satisfactory structure
  stretched over a couple of years, with periods of
  despondency that no solution existed.

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Finite Element Analysis
Swelling sets a requirementfor adhesive strength
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Adhesive Strength
After a long search, an suitable adhesive with
adequate strength was found.
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Creep
Both real time andaccelerated creepmeasurements
arebeing made.
Measurement showing creep following our most
likely estimate.
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Final Solution

• Free standing blocks of 31 layers glued together
• Thick enough to not buckle
• Odd number for symmetry
• Five touching blocks make a superblock
• 2 cm gap to allow for swelling and creep
• The whole detector contained between two
  bookends

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Review

• I discovered that John Hutchinson, a colleague
  whose office is down the hall from mine, is the
  world expert on some of the structural problems
  we had faced. So, as part of a series of outside
  reviews, we asked him to review the NOnA
  structure.
• His report on three aspects of our work
• The work appears to be highly professional in
  all respects
• performed with excellent technical judgment and
  considerable care.
• modeled in the most sensible manner possible

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Assembly Area

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Assembly Area
Block Assembly Platform
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Adhesive Dispenser
Vacuum Lifter
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Block Pivoter
Pivoting
Horizontal position
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Daves Retirement

• Dave has been the kingpin of the NOnA structure
  and assembly.
• In retirement, he will continue to help with the
  project.
• We all wish him a long and happy retirement.

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Backup Slides
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NOnA Timeline

• May 2002 1st Workshop
• Jun 2002 Letter of Intent
• Mar 2004 Proposal to the Fermilab PAC
• Mar 2005 Revised Proposal to the PAC
• Apr 2005 Fermilab Stage 1 Approval
• Nov 2005 CD-0 Granted
• Feb 2006 Recommended by NuSAG
• Oct 2006 Recommended by P5
• May 2007 CD-1 Granted
• Oct 2007 Passed CD-2/3a Review
• May 2008 CD-2/3a Granted
• Nov 2008 CD-3b Granted
• Apr 2009 Start of Construction
• Jun 2011 Far Detector Building Beneficial
  Occupancy
• Aug 2012 ? Mar 2012 1st 2.5 kT of the Far
  Detector Online
• Jan 2014 ? Aug 2013 Full Far Detector Online

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Reactor vs. Accelerator
Peter explained the physics of neutrino
oscillations well, so I need not repeat it.
However, I would like to expand on a couple of
points. Reactor and accelerator experiments do
not measure the same thing. Reactors are
sensitive to sin2(2q13), while accelerators are
sensitive to sin2(q23) sin2(2q13). If q23 ? p/4,
these quantities can be quite different. The
good news is that a comparison of NOnA and Daya
Bay can break this ambiguity and determine
whether n3 couples more to nm or nt.
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95 CL Resolution of the q23 Ambiguity
The ambiguity canbe resolved in the region
below and to the right of the curves. The
sensitivity depends on themass ordering, d,
and the sign of theambiguity itself. The
curves repre-sent an average over these
parameters.
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Measurement of sin2(2q23)
This calculationuses NOnAs excellent
energyresolution on nmCC events.
It is a parameterized calculation, which needs to
be redone witha full reconstruction.
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Sensitivity to sin2(2q13) ? 0
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Parameters Consistent with a 2 nm ? ne
Oscillation Probability
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Strategy for Determining the Mass Ordering

• If the CP-violating term goes in the same
  direction as the matter effect, then there is no
  ambiguity and NOnA can determine the mass
  ordering by itself, given sufficient integrated
  beam.
• If the CP-violating term goes in the opposite
  direction as the matter effect, then there is an
  inherent ambiguity and NOnA cannot determine the
  mass ordering by itself. But it can be
  determined, in principle, by comparing NOnA and
  T2K.
• If the neutrino oscillation probability is larger
  in NOnA than in T2K, it is the normal mass
  ordering if the opposite, it is the inverted
  mass ordering.

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95 CL Resolution of the Mass OrderingNOnA Alone
Normal Ordering
Inverted Ordering
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Combining Data with T2K

• When it is useful to combine data with T2K, I
  will assume that T2K will only run a neutrino
  beam because
• This is what they have proposed to do.
• They have less incentive to run antineutrinos
  since
• They have too short a baseline to get information
  on the mass ordering.
• The antineutrino rates at T2K energies are
  relatively somewhat lower than at NOnA energies.
• The complementarity between the two experiments
  is better statistically if T2K runs only
  neutrinos since it consists of comparing like
  runs neutrinos to neutrinos or antineutrinos to
  antineutrinos.

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95 CL Resolution of the Mass OrderingNOnA Plus
T2K
Normal Ordering
Inverted Ordering
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d vs. q13 Contours Best Possible d
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vs. q13 Contours Worst Possible dT2K and NOnA
Alone
Profiles, not limits
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d vs. q13 Contours Worst Possible dT2K and NOnA
Combined
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What NOnA Can Do If

• sin2(2q13) ? 0.1
• Determine the mass ordering for half of the d
  space at the 1-3 s level combining with T2K,
  determine the mass ordering for the other half of
  the d range at 1-2 s level.
• Exclude about half of the d space at the 1-2 s
  level.
• Combining with Daya Bay, determine whether n3
  couples more strongly to nm or nt at the 2 s
  level if sin2(2q23) lt 0.97.

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What NOnA Can Do If

• sin2(2q13) ? 0.06
• Determine the mass ordering for half of the d
  space at the 1-2 s level combining with T2K,
  determine the mass ordering for the other half of
  the d range at 1-2 s level.
• Exclude about half of the d space at the 1-2 s
  level.
• Combining with Daya Bay, determine whether n3
  couples more strongly to nm or nt at the 2 s
  level if sin2(2q23) lt 0.94.

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What NOnA Can Do If

• sin2(2q13) ? 0.03
• Determine the mass ordering for a quarter of the
  d space at the 1 s level.
• Exclude about half of the d space at the 1-2 s
  level.

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What NOnA Can Do If

• sin2(2q13) ? 0.01
• See a signal at the 1-3 s level, confirming weak
  signals seen in other experiments.

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What We Know and What We Dont Know
O. Mena and S. Parke, hep-ph/0312131
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NOnA Near Detector
The Near Detector will beplaced in a cavern
off of the MINOS access tunnel on the same off
axis line as the fardetector.
14.4 m
209 T 126 T totally active 23 T fiducial
4.1 m
Muon catcher 1 m iron
Shower containment region
Target region
2.9 m
Veto region