Transcript The SMRD subdetector at the T2K near detection station

The SMRD subdetector at the
T2K near detector station
Marcin Ziembicki
representing the SMRD working group
of the T2K collaboration
SMRD working group members
J. Brinson, B. Ellison, R. Gould, B. Hartfiel, N. Kulkarni, T. Kutter, J. Liu, W. Metcalf, M. Nauman, J. Nowak, J. Reid, D. Smith
Department of Physics & Astronomy, Louisiana State University, USA
D. Warner
Department of Physics, Colorado State University, USA
I. Danko, D. Naples, D. Northacker, V. Paolone
Department of Astronomy and Physics, University of Pittsburgh, USA
L. Golyshkin, A. Izmaylov, M. Khabibullin, A. Khotjantsev, Y. Kudenko, O. Mineev, E. Shabalin, N. Yershov
Institute for Nuclear Research, Moscow, Russia
S. Aoki, T. Hara, A.T. Suzuki, T. Yano
Kobe University, Japan
D. Kielczewska, M. Posiadala
Institute of Experimental Physics, University of Warsaw, Poland
M. Dziewiecki, R. Kurjata, J. Marzec, K. Zaremba, M. Ziembicki
Institute of Radioelectronics, Warsaw University of Technology, Poland
J. Blocki, A. Dabrowska, M. Sienkiewicz, M. Stodulski, A. Straczek, J. Swierblewski, T. Wachala, A. Zalewska
H. Niewodniczanski Institute of Nuclear Physics PAN, Poland
T. Kozlowski, J. Lagoda, P. Mijakowski, P. Przewlocki, E. Rondio, R. Sulej, M. Szeptycka
A. Soltan Institute of Nuclear Studies, Poland
J. Holeczek, J. Kisiel, T. Szeglowski
Institute of Physics, University of Silesia, Poland
J. Sobczyk, J. Zmuda
Institute of Theoretical Physics, Wroclaw University, Poland
T2K Overview
Kamioka
Super-K
22.5 kt
(FV)
295 km
Tokai
J-PARC Main Ring
750kW 30 GeV PS
• Measurement of 13
through e appearance
• Precise measurement of
23 and Δm223 through μ
disappearance
ND280 Off-Axis Detector
•
UA1/NOMAD CERN magnet
operated at ≤0.2 T magnetic field
•
Fine Grained Detector (FGD)
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Time Projection Chamber (TPC)
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SMRD
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ALL detectors installed
(except barrel ECAL)
Status: COMMISSIONING
Optimized for NC 0 measurement
Measure e contamination
Electromagnetic Calorimeter (ECAL)
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Measure charged particle momentum,
particle ID via dE/dx
Pi-Zero Detector (P0D)
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Measure  beam flux, E spectrum, flavor
composition through CC -interactions
Backgrounds CC-1
Measure backgrounds/pion cross section
Water and scintillator target
Photon detection (from 0) in P0D and
tracker
Side Muon Range Detector (SMRD)
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Measure momentum for lateral muons
Cosmic rays trigger
TRACKER
SMRD
SMRD – Concept & Tasks
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Measure muon momenta and angle from 
interactions
(with large angle to the beam)
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Cosmic trigger for the calibration of the inner
detectors
Beam monitor function is being studied
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Background rejection
 1.5E+6 interactions expected in the first year
 100k will give events with hits in SMRD
Modules:
• Horizontal (4 counters each)
• Vertical (5 counters each)
• Total of 440 modules (2008 counters)
875mm
SMRD Counters
Scintillator:
Polystyrene
1.5% PTP
0.01% POPOP
Chemical reflector
S-shaped grooves with WLS fibers
(Kuraray Y-11, S-type, 2.12 m length)
Special end-caps
on both ends
Light-tight enclosure &
stainless steel containers
Cosmic muon tests
Light Yield (single counter)
p.e.
cm
• L.Y. (sum of both ends)  25-50 p.e.
(center, T=20-22 C)
• Spatial resolution x = 6.1  0.8 cm
• MIP detection efficiency > 99.9%
SMRD Limit:
L.Y.(sum of both ends) > 20 p.e./MIP at 20 C
cm
Time Resolution & Delay
(single counter)
TDC
cm
L.Y. (center, 1000 counters)
cm
TDC step
50 ps
SMRD Modules
Optical connector with MPPC:
- Hamamatsu 667-pixel device,
- active area: 1.3x1.3 mm2,
- pixel size 50x50 μm2,
- bias voltage ~70 V,
- gain ~7.5x105
Aluminum
profiles &
fixing springs
Scintillators in light
tight, stainless steel
enclosure
Temperature sensor (DS18B20),
(2 per module, opposite sides)
Installation
UA1 Magnet:
• 16 C-shaped elements (8 rings)
• 16 48-mm thick iron plates for each C
• 17-mm air gaps
1 2 3 4 5 6 7 8
48
17
Installation tools
48
Springs
Aluminum profiles
Fixing Requirements:
• Feasible installation
• No movement once installed
• Protection from earthquakes
Installation (cont’d)
1)
Installation summary:
• March  July 2009
• All modules tested
after installation
99.8% WORKING
2)
3)
4)
5)
Signal Readout
Trip-t
HV Bias
High gain channel
Cal. pulse
CHi
Cg
Mini-coax
Low gain channel
CLo
MPPC
HV Trim
Trip-t Front-End Board (TFB)
Four Trip-t chips
64 channels per board
HV for sensors
Timestamping
Possibility of channel pairing
Global trigger primitives
signaling
FPGA
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Used by
SMRD
MPPC Issues
Signal proportional
to light intensity,
single photon ‘steps’
2 p.e.
APD pixel in
Geiger mode
Example response
0 p.e.
1 p.e.
Quenching
resistor
Gain  105106
Small, insensitive to magnetic fields
Relatively new sensor
 extensive testing was necessary
(revealed excellent sensor quality)
 nobody used it for long period (several years)
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Parameters highly dependent on
temperature
Monitoring required
Gain vs Voltage vs Temp.
x 10
Electron Gain
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15
10
5
T = 0C
T = 10C
T = 20C
T = 30C
T = 40C
T = 50C
5
0
65
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70
71
Supply Voltage (V)
On-Line Monitoring
Basic requirements
• Real time information analysis
• Raising diagnostic (Audio-visual) alarms
• Providing preliminary help for non-experts
On-going work
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o
o
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Channel histograms
Gain & dark rates
Temperature data
Per-channel history
Detailed alarms
Threshold settings
Physics data quality
monitoring
Reconstruction
• Select pairs of hits in coincidence window ~25ns
(max. time of the signal propagation through the fibre, plus est. time readout uncertainty)
• Reconstruct hit position
(only z-axis, along the scintillator, based on the time difference)
• Cosmic tracks – 3D fit to the reconstructed hits
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(Principal Component Analysis, straight line)
Various reconstruction approaches are being pursued for beam events.
all hits
ND280 software v7r5
hits in coincidence
Monte Carlo Study
no. of tracks
Reconstruction
Reconstruction Error
(maximum distance of the
reconstructed track to the real track)
m track bent, poor fit
distance (mm)
Straight m track, good fit
Example 1
Side view
ND280 software v6r1
Front view
Example 2
Cosmic muon trigger
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Purpose:
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Based on signals from SMRD
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Test and calibration (SMRD & inner detectors)
Also the downstream ECAL and first layers of P0D
are used
Trigger algorithm:
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Signals from both sides of the scintillator (coincidence
gate: 30 ns)
At least two such coincidences from one tower
Signals from two (or more) towers from different walls
(coincidence gate: 200 ns, because of the flight time)
Cosmic Muon Trigger Simulation
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Steps of the simulation:
1.
2.
3.
4.
5.
Muon flux on the Earth surface
Propagation through the rock surrounding the pit
ND280 simulation package
Propagation through the detector
based on GEANT 4
Simulation of the electronic signals
Applying of the trigger conditions
Preliminary studies show
cosmics simulation and
data to agree well
Simulation can be used for both
closed and open magnet positions
Summary
• Installation complete in July 2009
• On-line monitoring partially done
• Data taking seems to work, already
reconstructed cosmic muons tracks
• Current efforts:
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Monitoring beam structure
Reconstruction (different approaches)
Simulation
Cosmic trigger
Calibration
Slow control