Thursday, November 7th ECFA meeting - Valencia - A.-M. Magnan 1 CALICE Summary of 2006 testbeam for...
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Transcript of Thursday, November 7th ECFA meeting - Valencia - A.-M. Magnan 1 CALICE Summary of 2006 testbeam for...
Thursday, November 7th ECFA meeting - Valencia - A.-M. Magnan 1
CALICESummary of 2006 testbeam for the
ECALAnne-Marie MAGNAN
Imperial College London
On behalf of the CALICE-ECAL Collaboration
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Content
1. IntroductionBriefly, what does the ECAL look like ??The three 2006 test beam periods and their objectives
2. Data taken> 5 TBytes on disk, 65 million physics events
3. Electron and hadron eventsA few event displays.
4. Noise issuesA perfect detector would be amazing !
5. ConclusionA successful experience
Thursday, November 7th ECFA meeting - Valencia - A.-M. Magnan 3
200mm
360mm
360mm
The Electromagnetic Calorimeter prototype
• ECAL prototype:•30 layers of variable thickness of Tungsten•Active silicon layers interleved•Front end chip and readout on PCB board•Signals sent to DAQ
•W layers wrapped in carbon fibre• 3 modules with different tungstene thickness, total = 24 X0.•PCB+Si layers:8.5 mm
62 mm
62
mm
•6x6 1x1cm2 Si pads•Conductively glued to PCB
Active area of 12*18 cm2 now completed for 30 layersLast year : only 14 layers
Last 1/3rd expected in May 2007.
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Overall objective of 2006 beam test for ECAL
• Characterize detector performances.• Test and tune the simulation. Once we trust
the simulation optimisation of the ILC detector.
• Identify hardware problems to correct them before building the whole so-called EUDET module.
• Test particle flow algorithms.
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2006 beam test periods
Installation @ DESY . First cosmic events in the “tent”.Feb
May DESY TB area, 1-6 GeV electron beams, with only 24 layers .14 days in total.
July 27thAug 8th
ECAL CERN period : cancelled !! No beam, SPS fault, not ours....
AHCAL+TCMT period : transformed into 5 days ECAL+5 days AHCAL stand alone+ 3 days, courtesy of ATLAS, for ECAL stand alone.
Combined ECAL+AHCAL + TCMT , with ECAL-AHCAL @ 6cm
Aug 25thSept 6th
Oct 11thOct 30th
500 pedestal events
Data taking structure:
500 calibration
events
10k beam events500
pedestal events
...etc...
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Tracker: 4 drift chambersECAL: 24 layers, 5184 channels
First tests of ECAL-HCAL combined acquisition
DESY TB setup
ECAL at 0° : 3 position pointsAngle scan : 2 position points and angles studied : 10 °, 20°, 30°, 45°
For each point : energy scan with 1, 1.5, 2, 3, 4, 5, 6 GeV
Aiming at 100k events per sample
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DESY Data Samples
Shower fully contained
Garbage and empty events
Multi-particle events
Energy (mip) per event
Energy and angle scan completed, with ~200k events or more per point.
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CERN installation
Particle ID: Cherenkov counter, 1bit signal Tracker : 3 XY proportional chambers (MWPC) Calorimeters : • ECAL: 30 layers, 6480 channels• HCAL: 15 modules, 3240 channels• TCMT: 8 modules, 160 channels
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CERN- August period in figures
+ 30 Millions of Muon events for calibration.
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A few hadron runs combined with AHCAL and TCMT
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CERN October period
• Add another 27 Million physics events !+ 42M of muons for calibration+ 14M only for HCAL calibration+ 3.5 M of HCAL only runs+ 1.2 M “only” dedicated to beam tuning
• Detail of the 27 M:- Another 3.8 M dedicated to electron studies between
6 and 50 GeV- And 23 M of hadronic events between 6 and 80 GeV
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Electron runs
One point overlap with DESY TB at 6 GeV.
Electron combined runs
E (GeV)
e+ (kEvts)
e- (kEvts)
6 208 128
8 218
10 152 172
12 211
15 476 124
16 310
18 303 231
20 390 210
30 409
50 305
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Combined pion runs
E (GeV) π+ (kEvts) π- (kEvts)
6 480 1800
8 1800
10 960 1800
12 1600
15 720 1600
18 1700
20 770 1600
30 3300
40 1400
50 1500
80 1800
Hadron runs
With ECAL and HCAL at 6cm from each other this time !
EHCAL vs EECAL (mip)
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Summary of events
Size on disk: ~ 40 kB/evt 65M events = 2.5 TB for CERN Physics runs + 70 M = 3 TB for muon calibration runs
August period
October periodSept. break
μ calib. runs
μ calib.
See Roman’s Talkon Wednesday.
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Electron showering in the ECAL
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An hadronic event
10 GeV pion event, taken Oct 16th 2006
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A few problems, “of course”
1. Pedestal instabilities : results in “noisy” layers, with a correlated noise over a whole PCB of up to 50% of a MIP !!! – Not understood yet ! Currently investigating on an
hardware point of view.– A preliminary procedure to correct this effect event by
event is applied in the data reconstruction, but need further studies.
– the pedestals are measured at periods throughout the run so this effect can be tracked.
– This concerns only less than 3 PCBs over 30.
2. “Square events” : appearence of hits around some wafers, in the guard ring zone.
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Pedestal instabilities ...
Ex: Muon run (ECAL threshold : 0.5 MIP)Noise
Noise
A Good PCB
A PCB with unstable pedestals
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“Square” events ...
Proportion of events concerned :• high energy data (electrons 45 GeV) : ~4%• low energy data (electrons 3 GeV) : < 10-3.
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Conclusion
• A successful experience !!• Lots of data taken, stable detector running, people
on-site to solve the problems as soon as they appeared.
• Electron data samples from 1 to 50 GeV ready for analysis.
• Further plans : TB in May-June next year (currently in negotiation with CERN) with possibility to rotate both ECAL and HCAL+TCMT.
• + Fermilab with AHCAL in fall 2007, and DHCAL in winter 07/08.
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Thank you for your attention.
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CERN installation
Muon 1 Muon 2
400 m
beam
Beam instrumentation:1) ~500 m beam line after Be trg = magnets, collimators, secondary trg, abs2) Cherenkov detector for e/ separation < 40 GeV3) 3 x/y pairs of Multi Wires Proportional Chambers (MWPC) with double readout, multi-hit capability4) veto counter, r/o analog amplitude, to separate multi-particle events5) trigger system 2) 3) 4) 5) are integrated in the DAQ and read out event by event
3x3
10x10 trigger
11000
* all in mm
π event
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DESY installation
Thursday, November 7th ECFA meeting - Valencia - A.-M. Magnan 24
View of an ECAL board
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Beam quality issues @ DESY
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The data taken
CERF period: parasitic muonhigh intensity, wide distribution Very important for calibration !!!
All what was collected in the ECAL run:60 GeV secondary beam, tested e 10-45 GeV and 30-80 GeV.
Combined run, goal: ECAL EM program - e 10-45 GeV, from 50 GeV beam, with 0,10,20,30 deg - small samples of 30-80 GeV too large distance ECAL-AHCAL
AHCAL stand alone, ECAL removed- 1 day @ 10 GeV secondary beam tested / e 6,10,15,20 GeV- 3 days @ 50 GeV secondary beam e 10-45 GeV and p 30-80 GeV
!!! large fraction of time invested in beam tuning !!!
3 additional days “courtesy” of ATLAS: AHCAL and TCMT out of beam line, ECALre-installed for high statistics low energy runs (thanks to all voluntary shifters)
up to 10 million events in one day!