Transcript The MINOS Detectors - University of California, Santa Barbara

The MINOS Detectors
Chris Smith
California Institute of Technology
EPS Conference 2003
Outline
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The MINOS Experiment
 Detector Technology
 Far, Near and Calibration Detector
 Detector Performance
 Summary
The MINOS Experiment
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Two Detector, long baseline,
neutrino oscillation experiment:
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NuMI beam (Neutrinos at the
Main Injector)
Near Detector - on site at
Fermilab
Far Detector – 730km away in
Soudan mine, Minnesota
Calibration Detector – in a series
of test-beams at CERN
Oscillations lead to differences in
Near-Far event rates, energy
spectra
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Confirm Super-K result
Measure parameters to 10%
Far
Near
Chris Smith , Caltech
Detector Technology
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Iron/Scintillator tracking calorimeters
4.1 x 1cm scintillator strips, up to 8m long
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Readout via wavelength shifting fibres
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Extruded polystyrene (co-extruded TiO2 coating)
PPO (1%), POPOP (0.03%) fluors
Kuraray 1.2mm fibre (Y-11 fluor, 175 ppm)
Hamamatsu Multi-anode PMTs
Alternate planes rotated by  90o for 3D hits
Near and Far detectors magnetised
Chris Smith , Caltech
Far, Near and
Calibration Detector
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Detectors are designed to be as
similar as possible
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Far: Large octagon, 5400 tons
Near: Squashed octagon, 980 tons
Calibration: Small section, 12 tons
Chris Smith , Caltech
u
v
Near Detector - FNAL
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241 planes in 4 sections:
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Veto
Target
Hadron Shower
Muon Spectrometer
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Planes already
constructed at FNAL
Beneficial occupancy in
cavern from Dec 2003
Installation ~ 12 months
Chris Smith , Caltech
Far Detector – Soudan
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2 supermodules, 484 planes
Plane installation completed June
2nd Coil installed July
Cosmic ray veto shield
Unmanned running expected August
Already taking CR and atmos n data
Chris Smith , Caltech
Calibration Strategy
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MINOS designed for 2% relative (detector-detector)
and 5% absolute energy calibration
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Light Injection System
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Cosmic ray muons
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Electronics/PMT non-linearity
PMT gain shift
Strip-to-strip normalisation
Calibration Detector (CalDet)
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Characterise muon, electron and hadron responses
Understand event topologies
Test calibration procedures
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1 month running at FarDet  1 hour at CalDet
Chris Smith , Caltech
CalDet – CERN
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1x1m cut-out section of larger
MINOS detectors
60 planes x 24 strips for (x,y,z)
Double-ended read-out
Not magnetised
T11
x 60
24 strips
Steel Scintillator
3.6 GeV/c
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1m
1m
(3.7 m)
T7
10 GeV/c
5.9 cm
Chris Smith , Caltech
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CalDet exposed to
T7 and T11 beams
at CERN PS in
summer 2001, 2002
Provides e, m, p, p
from 0.2 – 10 GeV
Event Topologies at CalDet
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Particle ID using TOF and Cerenkov detectors.
2 GeV topologies (single view): (Without Single PEs)
Electron
Strip
Muon
Pion
Proton
Plane
Chris Smith , Caltech
Particle Response and Resolution
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Preliminary results from
CalDet agree well with
predictions
Response
Resolution
Hadrons
47 MIPs/GeV
55%/E
Electrons
60 MIPs/GeV
22%/E
MC expectation
Chris Smith , Caltech
Timing Resolution at the Far Detector
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Resolution determined by
decay time of Y-11 fluor in
WLS fibre ~8 ns
Resolution measurement
using down-going muons at
Far Detector ~2.6 ns/plane
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Time Residuals for CR Muons
Expect ~2.5 ns based on
photoelectron statistics for muons
Direction of muons can be
determined with ~10 planes for
contained vertex events
To distinguish up and down
through-going muons need
~20 planes
 ~ 2.6 ns
Time (ns)
Chris Smith , Caltech
Map of scintillator strip (Far Detector)
Light Output
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Factors affecting light at
phototube include
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Scintillator light output
Path-length in strip
Attenuation in WLS fibres
Connector efficiency
Apply corrections to infer
response for perpendicular
plane crossing (through
1cm scintillator)
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Fit to a muon energy spectrum
Observe ~8-10 PEs/strip
for cosmic ray muons at
surface
Chris Smith , Caltech
Candidate Neutrino Events at FarDet
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Contained vertex atmospheric neutrino event?
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Strip vs Plane
NO!
y
Strip vs Plane
x
U view
z
V view
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Y vs X
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CR muons entering
between planes mimic
atmospheric n events
MINOS uses a double
layer of scintillator to give
 95% efficiency and to
prevent gaps
Chris Smith , Caltech
Candidate Neutrino Events at FarDet
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Up-going muons produced by n
interactions in Earth’s crust
Time vs Y
y
x
Time vs Z
z
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Y vs Z
Y vs X
Strip vs Plane
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Chris Smith , Caltech
Example event: m+
p = 5.4GeV/c
Expect ~450 upgoing events in 5
year exposure of
MINOS
B field allows m
charge to be
measured up to
~100 GeV
Summary
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Far Detector construction completed on schedule
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Near Detector preparations underway
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Planes assembled on surface ready for installation
Beneficial occupancy in cavern from December ‘03
CalDet data-taking and analysis has produced
preliminary results
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Very successful installation
CR and atmospheric neutrino data regularly being taken
Data analysis underway
Good agreement with predictions
Test-beam run this summer will be used to compare Near
and Far detector electronics
MINOS is in good shape for NuMI beam in Dec ‘04!
Chris Smith , Caltech