NOnA and the US Neutrino Programme

1
NOnA and the US Neutrino Programme

• 
  Leslie Camilleri
• CERN, PH
• GDR Neutrino
• IPNO Orsay, 4 octobre
  2006

2
Plan of Talk

• Where do we stand and what do we still need to
  measure?
• NOnA
• The detector
• Its performance
• The NUMI beam
• Its present and future performance
• Its current user MINOS. Present and expected
  performance.
• NOnA sensitivity
• NOnA status and schedule.
• The US programme
• Accelerators
• Double b decay
• Reactors

3
3-family oscillation matrix
S sine c cosine

• d CP violation phase.
• q12 drives SOLAR oscillations sin2 q12 0.314
  0.056-0.047 (- 16)
• q23 drives ATMOSPHERIC oscillations sin2 q23
  0.44 0.18-0.10 (44 -22)
• q13 the MISSING link ! sin2 q13 lt 0.03 Set by a
  reactor experiment CHOOZ.

4
Mass hierarchySign of Dm223
ne
nm
nt
Normal Hierarchy
Inverted Hierarchy
Dm122 7.9 x 10 -5 eV2
m3
m2 m1
gt 0.05 eV2
Dm232 2.7 x 10-3 eV2
Dm232 2.7 x 10-3 eV2
m2 m1
Dm122 7.9 x 10 -5 eV2
m3
Oscillations only tell us about DIFFERENCES in
masses Not the ABSOLUTE mass scale Direct
measurements or Double b decay Upper limit
Tritium b decay mass (ne) lt 2.2 eV Lower limit
(2.7 x 10-3)1/2 gt 0.05 eV
5
Whats needed next?

• Determine q13.
• Determine the mass hierarchy.
• Any CP violation in the neutrino sector?

6
NOnA

• ??The NO?A Collaboration consists of 142
  physicists and engineers from 28 institutions
• ??Argonne, Athens, Caltech, College de France,
  Fermilab, Harvard, Indiana, ITEP, Michigan State,
  Minnesota-Twin Cities, Minnesota-Duluth, Northern
  Illinois, Ohio, Ohio State, Oxford, Rutherford,
  Rio de Janeiro, South Carolina, SMU, Stanford,
  Texas, Texas AM, Tufts, UCLA, Virginia,
  Washington, William and Mary
• ??Five Italian universities with about 20 senior
  physicists are actively discussing joining NO?A.
• Its main physics goal will be the study of ?µ??e
  oscillations at the atmospheric oscillation Dm2.

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Correlations in Oscillation Probability
From M. Lindner
Measuring P (nmne) does NOT yield a UNIQUE value
of q13 . Because of correlations between q13, dCP
and the mass hierarchy (sign of Dm231) CP
violation Difference between Neutrino and
Antineutrino Oscillations Mass hierarchy
accessible through Matter effects.
8
Energy dependence of matter effects

• In vacuum and without CP
  violation
• P(nm-ne)vac sin2 q23 sin2 2q13 sin2
  Datm
• with Datm 1.27 Dm232 (L/E)
• To be at maximum oscillation
• at L 800km E must be 1.64 GeV, and
  at L 295km E 0.6 GeV
• Introducing matter effects, at the
  first oscillation maximum
• P(nm-ne)mat 1 - (2E/ER)
  P(nm-ne)vac
• with ER 12 GeVDm232/(2.7x10-3)2.8
  gm.cm-3/r 12 GeV
• - depends on the mass hierarchy.
• Matter effects grow with energy and
  therefore with distance.
• 3 times larger (27) at NOnA (1.64 GeV) than
  at T2K (0.6 GeV)

9
NOnA Detector
Given relatively high energy of NUMI beam,
decided to optimize NOnA for resolution of the
mass hierarchy. Go as high in energy as
possible To keep L/E constant at 2.7 x 10-3
eV2 Go as far as possible, but remain in
US. At Ash River near Canadian border (L
810km) New site. Above ground. Detector
placed 14 mrad (12 km) Off-axis of the Fermilab
NUMI beam (MINOS).
10
NOnA Detector
Fully active detector consisting of alternating
planes of horizontal and vertical 15.7m long
plastic PVC tubes filled with liquid
scintillator (BC 517L) Total mass 25ktons. Each
tube viewed by a looped WLS fibre both ends of
which are read by a single avalanche photodiode
(APD).
760 000 cells
TiO2 Coated PVC tubes
n
Tubes are wide enough (6 cm) to allow large
bending radius and no damage to fibre ?The loop
is a perfect mirror
11
Avalanche Photodiode
Photon

• Hamamatsu 32 APD arrays

• Pixel size 1.8mm x 1.05mm
• (Fibre 0.8mm diameter)
• Operating voltage 400 Volts
• Gain 100
• Operating temperature -15o C
• (reduces noise)

Asic for APDs 2.5 pe noise
12
Why APDs ?
The quantum efficiency of APDs is much higher
than a pms 80 . Especially at the higher
wave lengths surviving after traversing the
fibre.
13
Fibre/Scintillator cosmic ray test
Inserted looped 15.7m long fibre in 60 cm
long PVC tube filled with liquid
scintillator. Exposed to cosmic rays.
0 20 40 60 80 pe
Measured 20 p.e. for a mip signal at the far end.
Asic for APDs 2.5 pe noise ? S/N 8
14
Half Block Prototype Being Builtat Argonne
15
Location
Surface detector with about 3m
overburden to reduce the em component of
cosmic rays.
16
nm/nediscrimination
ne CC
nm CC
Electrons shower many hits/plane. Muons do not
just one hit/plane.
nm CC background rejection 7.1 x
10-4
17
Neutral Current background ??N???p?o
Look like electrons and ne CC, if two photons are
not recognized. nm NC background rejection 1.3
x 10-3
18
The MINOS/NOnA Neutrino beam NUMI.
Move horn and target to change energy of
Beam
19
OFF-AXIS Technique
Most decay pions give similar neutrino energies
at the detector
Neutrino Energy Spectrum is narrow
know where to expect ne
appearance Can choose the off-axis angle and
select the mean energy of the beam. (
Optimizes the oscillation probability)
20
The Neutrino Beam components
nm ? nt
Signal Sin2 2q13 0.04
Beam ne 0.5 Major background
Will have a NEAR detector to measure this ne
spectrum
21
MINOS detector
Study of atmospheric mass region through nm
disappearance
22
Far detector results
Expected unoscillated
Suppression of events at low energy
23
New MINOS measurements
K2K
(Experiment ended)
Compatible with and comparable to SK More precise
than K2K.
24
The MINOS future
MINOS baseline 3.4 x 1020 pots / year
Improvement by about a factor of 3 in 3 years
25
The Proton Beam as of today
2.8 x 1013 ps per spill (2.2 secs)
280 kW
For a Fermilab year of
2 x 107 secs
2.4 x 1020 pots/year.
(Achieved 1.27 x1020 in first turn-on year)
MINOS baseline 3.4 x 1020
pots/year.
26
The n beam after the collider shuts down (2009)

• No antiproton production batches in Main Injector
• No downtime for preparing collider shot. No time
  for antiproton transfer
• from accumulator to recycler.
• Transfer time of 12 booster batches to Main
  Injector (0.8 sec).
• Instead transfer them to recycler during Main
  Injector cycle, and then transfer
• in one go
• New RF in main injector
• Upgrade of NUMI target.
• This should bring the
  Main Injector to a 1MW level
• 
  Cost 30-50 M

27
Beam assumptions

• 2010 Full shutdown to convert MI to 1 MW
  machine.
• 2011 44 weeks running at 400 to 700 kW (Partial
  (5kT)detector)
• 2012 38 weeks running at 700kW to 1 MW.
• 2013 and beyond 44 weeks at 1 MW.

• Degradation factors assumed
• Accelerator uptime 85.
• Average to peak intensity 90.
• NOnA uptime 90.

• Running time
• Start running as soon as 5kT installed.
• 2 years to build up to full detector.
• Run for 6 years from end of construction.
• Total 60.3 x 1020
  pots

28
Signal and background I

• 6 electron shower energy resolution
• 3.5 muon energy resolution
• Maximum likelihood applied to events to separate
  ne events from background.
• Yields 23 efficiency for ne signal events
  including fiducial inefficiency
• Background suppression
• 7.1E-4 nm CC
• 1.3E-3 Neutral Current
• Optimized Figure of Merit
• Signal / sqrt(bkd) 32
• 140 signal events for 60 x 1020 pot for sin2
  2q13 0.1
• 19 background events. (12 intrinsic beam ne and
  7 neutral currents)

29
Signal and Background II

• Statistical Power why this is hard and we need
  protons

0.01 0.05 0.1
0.01 0.05 0.1
For sin2 2?13 0.1 ? S142.1, B19.5 ?
S 71.8, B12.1
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3 s sensitivity to q13 0
30.2 x 10 20 pot each n and
n. (removes some correlation)
n only 60.3 x 1020 pot
The correlations are much reduced by running BOTH
n and n. Discovery limit is better than 0.02 for
ALL ds and BOTH mass hierarchies.
31
Comparison to T2K and a Reactor Experiment
T2K
Reactor
T2K may not be latest
Braidwood Double Chooz
Comparable to a Very sensitive
reactor experiment
Not very different
32
95 CL Resolution of the ?23 Ambiguity
Combining accelerator experiments (sensitive to
sin2(?23)sin2(2?13)) with
reactor experiments (sensitive to sin2(2?13))
33
95 CL Resolution of the Mass Ordering

• Important to establish hierarchy
• Per se
• If inverted next generation of
• double beta decay experiments
• can determine if the neutrino is its
• own antiparticle.
• To measure CP violation
• need to remove hierarchy uncertainty
• because it contributes an
• apparent CP violation.

Will depend on value of q13 !!
34
Combining NO?A and T2K
?m2 0.0030 eV2
Some improvement at high values of q13.
35
d vs. sin2(2?13) Contours for Test pointsNormal
Mass ordering
Normal Mass Ordering
Some limited sensitivity at 1 s
36
Cost and schedule

• Total cost (Far and near detectors, building,
  admin etc)
• 226 M
  (including 57 M contingency)
• Status
• Approved by Fermilab Program Advisory Committee
  Stage 1 Approval, (April 2005).
• Prioritized by NuSAG.
• Recommended by P5 for construction start in
  Fiscal Year 2008 (October 2007).
• Critical Decision Zero (CD0) granted. Mission
  need.
• Obtained CD1 approval Range of Schedules and
  costs.
• CD2 next end 2006(?) Final cost, schedule and
  TDR.
• Granted 10M in RD for generic oscillation
  experiment.
• Proton Driver CD0 shelved at this stage. But RD
  can continue.
• Alternative plans for Main Injector
  upgrade to 1 MW, maybe 1.2 MW.
• Schedule
• Assumption Approval early 2007.
• Building ready June 2009. (Agreement with U. of
  Minnesota).
• Five kilotons Early 2011.
• Completion 2012.

37
The US programme Accelerators I.

• MINOS.
• MiniBooNE nm?ne search
• at the Fermilab booster
• Results on
• the LSND observation this year.
• High energy data already presented.
• SciBooNE K2K SciBar detector
• In MiniBooNE beam
• low energy cross sections
• MINERVA. n cross sections
• at low energy in the
• near hall of NUMI beam.
• Going through approval
• process

38
The US programme Accelerators II.

• T2K 280m Participation in 280m near detector
  supported.
• p0 detector inside the UA1/NOMAD
  magnet for the near detector and work on
  beam.
• T2K 2Km Participation in Water Cerenkov, civil
  engineering and liquid argon (150 tons).
• Only at later stage if possible.
• Liquid argon RD to determine whether scalable
  to tens of kilotons.

39
The US programme Double b decay.
EXOPotential for reducing the background by
extracting and identifyng resulting Barium
atom as a second stage
NuSAG recommendations Recommended the first three
40
The US programme Reactors.

• NuSAG recommended a US experiment to get down to
  a sensitivity of
• sin2 2q13 of 0.01. Both Daya Bay and
  Braidwood had this potential.
• The DOE has stopped Braidwood and encouraged Daya
  Bay.
• NuSAG encouraged participation in Double Chooz
  but with lower scientific priority because of its
  lower reach.
• The DOE does not go along with this but possibly
  the NSF will.

41
Very Long baseline New NuSAG charge.

• Assume a MW accelerator.
• Discuss baselines Compare 800km (NOnA),
• to 1300-2800km baselines Fermilab
  or Brookhaven to new Underground site at
  Henderson or Homestake.
• Types of detectors Liquid Argon or Water
  Cerenkov?
• Broad band covering several oscillation maxima
  at once or narrow band.
• Sensitivity and physics programme.
• Joint BNL/FNAL study currently being carried out
  on these issues.
• Report Oct. 2006

42

• Extra Slides

43
Cost breakdown
44
Far detector
45
Near Detector in MINOS Surface Building
6.5 x 1020 pot in 75 mrad off-axis beam
Kaon peak
45,000 nm CC events
2,200 ne CC events
46
Confirmed by KAMLAND Reactor antineutrinos to
detector at Kamioka
KAMLAND
Solar Experiments
KamLAND Solar Completely consistent
47
New MINOS measurements
(Experiment ended)
48
Why are neutrino masses so low????
Other particles
Fascinating !!!!!
Also Lower limit
(2.4 x 10-3)1/2 gt 0.05 eV
49
APD response

• Measured with light equivalent to one and two
  mips

Noise
Signal well separated from noise
0 20 40 60
80 pe
50
Summary of backgrounds
Efficiency for ne signal 24
51
8-fold degeneracies

• q13 - d ambiguity.
• Mass hierarchy two-fold degeneracy
• q23 degeneracy For a value of sin2 2q23, say
  0.92, q23 can be 33.5o or 56.5

A measure of Pme can yield a whole range of
values of q13 Measuring with ns as well reduces
the correlations
NOnA will most probably run first 3 years with n
and then 3 more with n This will also improve the
complementarity with T2K if they run n only.
52
The road ahead
53
Particle Physics Projects Prioritization Panel
(P5) June 2006
October 2007 -gt October 2008
54
Initial Tests Using Extrusions from Existing Die
(Smaller)
3.87cm 6cm Final Design
N 80 exp(-L/4.6)10 exp(-L/5000)
Measured light yields
Geometry gives factor of 1.75
13 p.e. at 15.7m
13 pe goes to 23 pe
Reflectivity gives factor of 1.2
23 pe goes to 27 pe
Titanium dioxide
55
Far Detector Assembly

• Detector has 64 (31-plane) blocks
• Can fill with scintillator and run during
  construction
• Half-Size planes built tested at Argonne

1-cm expan- sion gap
31-plane block
31-plane block
56
Near Detector to understand the beam
262 T 145 T totally active 20.4 T
fiducial (central 2.5 x 3.25 m)
8-plane block 10.6 T full 1.6 T empty
9.6 m
5 m
Muon catcher 1 m iron
Shower containment region
Target region
3.5 m
Veto region
57
nm- ne separation
Low energy
High energy
Electrons (shower)
Electrons (shower)
Muons
Muons
nm CC background rejection 7.1 x 10-4

58
Near detector locations
Site 1.5
n beam
Far