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NuMI Off-Axis Experiment. Alfons Weber University of Oxford & Rutherford Appleton Laboratory EPS2003, Aachen July 19, 2003. Content. What is the physics? Why off-axis? The beam The site What experiment to build? Scintillator Resistive plate chambers (Liquid Argon) Sensitivity. - PowerPoint PPT Presentation
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NuMI Off-Axis Experiment
Alfons Weber
University of Oxford &Rutherford Appleton Laboratory
EPS2003, AachenJuly 19, 2003
19/7/2003 2
Content What is the physics? Why off-axis?
The beam The site
What experiment to build? Scintillator Resistive plate chambers (Liquid Argon)
Sensitivity
19/7/2003 3
What is the Physics? Precision Experiment to determine
m23
sin2223
Look for sub-dominant oscillation mode sin213
Needed: low background Low e beam contamination Few wrong energy neutrinos
e
19/7/2003 4
Why Off-Axis
e (|Ue32| = 0.01) e background
NC (visible energy), no rejection
spectrum
NuMI beam can produce 1-3 GeV intense beams with well defined energy in a cone around the nominal beam direction
19/7/2003 5
NuMI beam 120 GeV protons from
FNAL main injector 3-15 GeV neutrinos 3.8x1020 PoT / year 0.5 MW beam power
Baselines 700-950 km
Several sites with infrastructure
Road Electricity Network
Possible Sites
Canada
U.S.
L. Superior
Soudan
19/7/2003 6
Experimental Challenge Small signal
huge # NC Surface detector
No or light over-burden
cosmic induced n But:
Duty factor 10-5
19/7/2003 7
Detector Challenge NC versus Electron CC separation
Fine grain Low Z
Build affordable & massive detector 50+ kton fiducial mass >400k readout channels
Technologies: Solid scintillator (MegaMINOS, but not Mton) Liquid scintillator Glass RPCs (Liquid Argon TPC)
19/7/2003 8
Alternating horizontal and vertical scintillator planes
Passive material: woodOriented Strand Board (density .6 - .7 g/cm3)
Sampling: 1/3 rad. length
readout
read
out
read
out
15 m 15 m
15 m
Scintillatormodules4 ft
48 ft
8 ft 8 ft
8 in
9.4 tons
5300 = detector
6 = 1 plane
180 m
885 planes = detector
Fiducial fraction (1 m cut at all edges) 80%
Solid/Liquid Sintillator
19/7/2003 9
Scintillator Length 15 m Looped fibre readout
Scintillator Material Solid
MINOS like co-extruded (3.8x1 cm2)
Liquid Bicron 517 L (3.8x2.9 cm2)
WLS Fiber Kuraray (0.7 mm ø)
Photodetector APD PMT: M64
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
0 500 1000 1500 2000
LED 1.2mm PMT
LED 1.2mm APD
LED Ratio
Length in cm
Rel
ativ
e L
igh
t Y
ield
MINOS WLS Fiber
680,000 channels( 30 x MINOS)
( 2 x MINOS)
Scintillator and WLS Fibre
400,000 m2
( 16 x MINOS)
19/7/2003 10
Glass RPCs / LSTs
Used successfully Belle: 4 years operation Virginia Tech: 5 years testing
Wood/plastic absorber
19/7/2003 11
Signal & BG Events
typical signal event BG event
Fuzzy track = e- Clean track = muon2 tracks = π0
19/7/2003 12
Physics Reach (I) Phase I (2008-2014)
4x1020 PoT / year 50 kton detector
(fiducial) 1.5 years neutrinos 5 years anti-neutrinos
Phase II (2014-2020) A factor of 25 more:
PoT x detector mass 1.5 years neutrinos 5 years anti-neutrinos
19/7/2003 13
Physics Reach (II) Some Math:
need more than one experiment to determine oscillation parameters
A. Cervera et al., Nuclear Physics B 579 (2000) 17 – 55,
expansion to second order in 12 1213 12
23
, , , LA
P ( e) = P1 + P2 + P3 + P4
19/7/2003 14
Physics Reach (III) Measurement is oscillation probability Depends simultaneously on:
Mass hierarchy CP phase Mixing angles Typical Errors
19/7/2003 15
Summary The NuMI OA group is seriously trying to bring froward a
credible & affordable proposal Combination of
JPARC/SuperK and NuMI OA neutrino and anti-neutrino running
might reveal neutrino mixing parameters Masses & hierarchy Angles CP phase
For more information:
http://www-off-axis.fnal.gov
19/7/2003 16
Liquid Argon TPCExcellent pattern recognition capabilitiesHigh efficiency for electron identificationExcellent e/0 rejection
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