Transcript Slide 1

NOºA
The NuMI Offaxis ºe Appearance Experiment
Andrew Norman for the NOºA Collaboration
NuFACT07, Okayama Japan
August 11, 2007
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Introduction
 Physics Motivation
 Sensitivities
 Detector Design
 R&D Progress
Ash River
International
Falls
Duluth
 Status
Minneapolis
Fermilab
Overview: NOvA Today (Baseline)
 NOvA is an 18kTon far detector +
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218Ton near detector + NuMI beam
upgrade project.
Both detectors are “totally active” liquid International
Falls
scintillator designs
The detectors are 14mrad off the
primary beam axis to achieve narrow º¹
energy spectrum, peaked at 2GeV.
The far detect sits on a 810km baseline
between Chicago and Northern
Minnesota at the first oscillation maximum
Designed to use the 320KW then 700KW
NuMI beam with final upgrade to the
1.2MW “super-NuMI” beam from the
Fermilab main injector.
Integrate ultimately 10£1020 pot/yr
Ash River
Duluth
Minneapolis
Fermilab
Physics Program
 The NOºA experimental program goals:
 Observe º¹ ! ºe oscillations
 Measure µ13
 Or improve the current limit on µ13 by a factor of 20.
 Measure sin2(2µ23) to a precision of 0.5-1%.
 Resolve the neutrino mass hierarchy
 Measure the CP violating phase ±
 Measurement of NC cross section at 2 GeV
 Detection of near galactic supernova
The Effect of Going Off-Axis
 By going off-axis, the neutrino
flux from ¼ ! ¹ + º is reduced at
a distance z to:
2 A
F = ( 1+ 2°
)
2
2
° µ
4¼z 2
 But the energy narrows as µ2:
Eº =
0:43E ¼
1+ ° 2 µ2
 For NOνA, moving 14 mrad off
axis makes the NuMI beam
energy
 peak at 2 GeV
 Eº width narrows to 20%
 This corresponds to the first the
oscillation maximum
1st Osc. Max
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The Effect of Going Off-Axis
• This suppresses the high
energy tail (NC background)
• Significantly reduces the
Kaon background
contribution by shifting the
neutrino energy away from
the signal band
• Energy spectrum in the signal
region becomes almost
insensitive to the /K ratio
• Results in a neutrino peak
primarily from  decays
20
On Axis (π)
18
º’s from K’s well
above signal band
On Axis (K)
16
π 14mrad
14
K 14mrad
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Eν(GeV)
Eº K =
0:96E K
1+ ° 2 µ2
Offaxis νμ Energies from π/K
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8
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º’s from ¼’s in 2GeV band
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2
0
0
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5
10
Eπ/K GeV
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20
P(º¹ ! ºe) and Ue3
The Ue3 contribution to the third mass
state is small, requiring a precision
measurement of ºe appearance
 Measuring a ºe excess in the NuMI º¹
beam will give evidence for º¹! ºe
transitions and a non-zero Ue3 component
to ¢ m232
 This is done through the ºe CC channel
º3
 The º¹ NC is the dominant background,
 Controlled through the identification of
initial vertex and displaced shower
conversion point.
 NOºA’s energy (2GeV) and baseline
º2
(810km) and segmentation (0.15X0) are
chosen to maximize the physics reach of
accessing these transitions
º1
 Electron neutrino’s role in the º¹ flavor
transitions is given an upper bound by
CHOOZ limit at 5-10% of the total state.
¢ m2at m
ºe Charged Current Channel
Event Parameters
Reaction:
º ep ! p¼+ e¡
Primary Vertex
Eº = 2.5GeV
Ep = 1.1GeV
E¼ = 0.2GeV
Ee = 1.9GeV
Shower spans »65
of the 1178
planes
Localized E&M Shower
º¹ Neutral Current Background
Event Parameters
Reaction:
º eN ! p¼0 º ¹
Primary Vertex
Eº = 10.6GeV
Ep = 1.04GeV
E¼ = 1.97GeV
Suppressed by
vertex/shower
displacement
identification
Localized E&M Shower
Displacement
Sensitivity at 3¾ for µ13 from º¹ ! ºe
 For the current 18kTon
detector, with 700kW
(dashed) and 1.2MW
(solid) beam.
 The physics reach for
µ13 is shown for 3
years of running each
on º and º-bar.
 The reach of the
1.2MW is almost an
order of magnitude
beyond the CHOOZ
bound, giving
improvement over
the 3¾ MINOS reach
Sensitivity to sin2(2µ23)
 NOºA can perform the
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disappearance measurement to
a precision of 0.5-1%
Proceeds as a parameterized
analysis of quasielastic º¹ CC
events
If 1, then resolve quadrant
(µ23 > ¼/4 or µ23 < ¼/4, )
Measure if º3 couples more to
º¹ or º¿
Resolve ambiguity by
comparing NOºA to Daya Bay.
Mass Ordering
 From solar and atmospheric data we
know:
¢ m223
¢ m212
• This leads to two possible mass
hierarchies
• A “natural” order which follows the
lepton mass ordering
• An “inverted” order where m3 is
actually the lightest
• NOºA can solve this by measuring the
sign of m23 using the MSW effect over
the 810km baseline
¢ m2sol ar
¢ m2at m
Sensitivities for P(º¹ ! ºe) = 0.02
 Some CP phases
create an ambiguity
in the resolution of the
mass hierarchy.
 Combine with a
second measurement
to break ambiguities
CP Violation
 Large Mixing Angle (LMA) solution gives sensitivity in º¹ ! ºe
transitions to the CP violating phase ±.
 In vacuum, the transition probability is shifted with ±. At the first
oscillation maximum the shift is:
q
j¢ P± (º ¹ ! º e)j » 0:06%
 Since the shift is proportional to
p
si n 2 2µ1 3
0:05
si n2 2µ13 the importance of the
2
sub-leading terms grow, as si n 2µ13 gets small.
 The ultimate sensitivity of
NOνA for resolving the CP
ambiguities in matter depend
on both sin θ13 and ±
 Combining the NOºA result
with other experiments lifts
the ambiguities in some
regions.
Resolution of Mass Hierarchy
(95% CL)
Normal
Inverted
The NOνA Detectors
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Far Detector
18 kTons
1178
alternating X-Y
planes
Grouped into
38 modular half
kiloton “blocks”
Over 450,000
independent
detection cells
> 70% of total
mass is active
18,000 tons
218 tons
88 tons
45 tons
4.2 m
Far
Detector
4.2 m
Near
Detector
How big is this?
The NOvA far detector is big
enough to fit Atlas, CMS, DØ, and
CDF Inside it’s active volume.
IPND
Humpback
Whale
IPND
The “Integration Prototype Near
Detector” will be built in Q1 2008 to
show technological integration of all
the NOvA subsystem
NuMI Beam Options
 Two intensity options
 700 kW (ANU baseline)
 1.2MW (super-NuMI)
 1 year of beam = 44 weeks of running
 Duty factor = 0.6 (accel + NuMI down time)
 Run 3 years each on º and º-bar
 For 700kW this is 36£1020 pot
 For 1.2MW this is 60£ 1020 pot
NuMI Accelerator Upgrade
New extraction line from
Recycler to MI
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Beamline Upgrade
Proton source upgraded from
320kW to 700kW
NuMI will deliver 4.9×1012
protons per pulse
1.33s rep-rate.
This results in 6×1020 pot/yr.
New Injection line from
MI to Recycler
&
Recycler
New RF stations added
and acceleration rate
switched to 240GeV/s
Changes
•Recycler runs proton not anti-protons
•New injection/extraction lines for Recycler to Main
Injector transfers
•Main Injector cycle time reduced from 2.2s to 1.5s
(stack in the recycler)
•Cycle time reduced again to 1.33s with 2 more RF
stations at MI-60 and with transition of the MI from 204
GeV/s to it’s design acceleration rate of 240 GeV/s.
•NuMI target redesign for high flux
Detector Modules
NOνA Modules
 The NOνA detector module forms
the base unit for the detector.
 Each module is made from two 16
cell high reflectivity PVC extrusions
bonded into a single 32 cell module
 Includes readout manifold for fiber
routing and APD housing
Two 16 cell extrusions
 Combined 12 module wide X or Y
measuring planes.
 Each module is capped, and filled
with the liquid scintillator.
 These are the primary containment
vessel for the 3.9 million gallons of
scintillator material.
 There are 14,136 detector modules
with a total of 452,352 separate
detection cells in the NOνA Far
Detector.
PVC Extrusions
Single Cell
15.7m
One Module
1.3m
6cm
3.9cm
Each extrusion is a single 15.7m (51.5ft) long set of 6x3.9cm cells.
Two extrusions are joined to form a single 1.3m wide module
NOºA Approval Status
 CD-1 completed and signed.
 Total project capped at $260M
 Includes Accel. Upgrade to 700kW
 FNAL Director’s review (Part 1) June ’07
 Baseline detector size 18kton
 Physics & detector sub systems reviewed -- PASSED
 Costs rolled up
 Initial estimate placed detector over project cap
 Included many obvious accounting errors
 July/Aug costs for project “scrubbed” to remove anomalous
entries, redundancies and errors…
 FNAL Director’s review (Part 2) Aug. ‘07
 Primarily cost accounting review
 DoE CD-2/CD-3a review scheduled for Oct. ’07
NOºA Time Line
 Now Electronics, PVC, Scint, DAQ, DCS, SIM R&D
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ongoing and continues through 2008/9
Q1/Q2 2008 IPND installation in MINOS assem.
Building
Q1/Q2 2008 Far site infrastructure start
2010 Collider shutdown, NuMI upgrades
2011 Beneficial Occupancy at Far Site
2011-13 Installation/Commisioning/Production data
taking occur in parallel
The Far Site - Ash River, MN
Ash River is chosen as the site for the massive 18kTon far detector because it is the farthest site
from Fermilab that is still inside the United States and yet accessible by roadway. The site is
810.5km from Fermilab, 1.5 miles south of Voyageurs National Park, and 45minute away from
the town of International Falls, known as “The Icebox of the Nation” for it’s record breaking
winter time temperatures.
N
0
25
50 km
The NOνA Site Today
Voyageurs
National Park
Ash River
Off Axis?
By placing the detector at Ash
River, 14.6mrad off of the NuMI
beam axis, we obtain a sharp
peak at 2GeV in the neutrino
energy spectrum.
NuMI
at NOνA
gives a
2GeV peak