Transcript Identificazione e ricostruzione di elettroni e fotoni in CMS

ECAL perfomance:
lessons learned and future plans
P. Meridiani & C. Seez
Physics Days
17/01/2007
Paolo Meridiani - INFN Roma1
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Lessons/achievements of PTDR [1]
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Test beam 2004 results show that ECAL “intrinsic
performance” is as expected
Paolo Meridiani - INFN Roma1
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Lessons/achievements of PTDR [2]
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Important lesson from 2004 TB:
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Amplitude reconstruction from digitized time samples
• Only a single set of weights required for all channels
• Only asynchronous (test beam) running requires finely tuned weights
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Event by event pedestal subtraction, using “presamples” is important
and useful
Using more than one weight on the signal gives only very small (5%)
reduction of energy equivalent noise
Paolo Meridiani - INFN Roma1
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Lessons/achievements of PTDR [3]

Performance in CMS dominated by:
• Tracker material
• Calibration issues
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The big issue for ECAL is calibration
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27/52 pages in ECAL chapter were on this topic
Understanding of the tracker material effects is one the biggest
challenge for the in-situ calibration
Includes also the correction for radiation induced transparency
changes using the laser system
Paolo Meridiani - INFN Roma1
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Since PTDR

2006: “integration” of the various components which will
be used for the final CMS setup
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DAQ
Offline software
DQM
Many objectives have been achieved:
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Transition to CMSSW of the ECAL Local Reconstruction code &
simulation
CMSSW DQM version
Cosmic intercalibration campagn
Test Beam campaign
• Ecal test beam in H4
• ECAL + HCAL test beam in H2

MTCC
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Local Reconstruction code
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Simplification of the data tiers profiting from the EVD
restructuring
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Implementation used methods demonstrated in the 2004
test beam
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Local reconstruction integrated with the condition DB
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Whole procedure (reconstruction code + condition
evaluations) fully validated using the test beam data

At the moment the code is rather stable and no big
changes are foreseen for the future
Paolo Meridiani - INFN Roma1
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Simulation
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Hits
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No big development w.r.t. to OSCAR. Mostly a porting of the
existing code
Major ECAL development was the support of the test beam setups,
previously not included in OSCAR. More work is needed to include
also the beam line components
Current work mostly concentrated in the comparisons between
Geant 4.8/4.7 versions together with comparison with the test beam
data
Digitization

Completely rewritten w.r.t. to ORCA
• Moved to MGPA electronics
• Simplified the code in many areas to make it more mantainable

Work is still needed in the trigger primitives emulation
• EE electronics mapping is still lacking. Some action is needed here
Paolo Meridiani - INFN Roma1
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DQM [1]

In the 2006 the ECAL DQM moved from the standalone version used
in the cosmic setup to the CMSSW DQM architecture

It has been used in all the 2006 tests (H4,H2, cosmic, MTCC, DAQ
integration center)

Proved to be in good shape for detector specific monitoring, under
real-life stress-test conditions

Heavily used for debugging purposes in the test beams
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Simple access to all high-level products used in analysis, thanks to
the re-use of standard CMS framework/code
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Costantly under development and continuous update/ upgrade/
improvements
Ready to be moved to the final CMS setup version

Paolo Meridiani - INFN Roma1
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ECAL DQM - web static pages
DQM [2]
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Cosmic Intercalibration
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Every integrated SM is/will be tested for
around one week using a specific cosmic setup
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10° inclined SM
APD HV raised to have gain 200
About 5 million triggers are collected for each
SM
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So far 22 SMs have exposed to cosmic rays
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Useful for two main reasons
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Initial commissioning of the integrated SM
Preliminary intercalibration coefficient can be
computed at a precision of around 2% for all
channels
Systematics w.r.t to beam intercalibration are
under detail study
Paolo Meridiani - INFN Roma1
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TB06 campaign [1]
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Two setups, both have been a great success
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H4
• ECAL only, 10 SMs have been tested. 1 SM has been tested twice
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H2
• ECAL + HCAL, lots of data with different beams (e, p+ ,p- on target) and
E (1300GeV)
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First real integration tests DAQ + DQM + Offline CMSSW
software
• H2 ECAL + HCAL DAQ have worked together
Paolo Meridiani - INFN Roma1
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TB06 campaign [2]

Analysis is still going on for both TB data
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Different intercalibration techniques have been tested on
the real data both in H4 & H2
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Reproducibility below 0.3%
The 10 beam intercalibrated SMs will play an important role at the
beginning of the LHC operations in order to understand calibration
systematics of the in-situ method
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Full validation/tuning of the simulation is going on. This
will be the starting point for the CMS simulation
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H2 is fundamental to make the ECAL+HCAL system to be
used as a single combined calorimeter
Paolo Meridiani - INFN Roma1
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Clustering workshop (November 2006)
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Excellent performance and extensive understanding of
details of cluster and supercluster reconstruction in PTDR
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Time now for simplification, unification, systematization of
knowledge/algorithms/code
This stage was begun in “Clustering Workshop” in October 2006
• Need for agreed definition of Calibrated RecHits
– And Monte Carlo data should correspond to ‘calibrated real data’ if the definition differs
• Clear and clean separation of “Calibration” and “Corrections”
• Appropriate clustering for all energies
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Follows natural and logical progression:
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Obtain best performance using any means to hand
• Building up understanding of the details and issues
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Go back and simplify, consolidate, unify, without sacrificing the
performance
Paolo Meridiani - INFN Roma1
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PiZero Calibration
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Important progress on π0 intercalibration
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Work done with OSCAR/ORCA system: approval will be sought for
AN soon
• Internal notes from Rome, CalTech, UCSD and Minnesota are being
amalgamated
• Demonstration of the ability to select pi zero events online and create a
special stream for calibration is still lacking
First resonance seen in CMS :-D
H2 Data
Paolo Meridiani - INFN Roma1
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Ecal Geometry
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Old xml “hardcoded” Ecal Geometry needs to be changed
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Not updated for non-crystal support, cooling, readout
Not mantainable
Not usable for alignment purposes
• Primary d.o.f. is the supermodule alignment
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First implementation is delivered for the barrel (B. Heltsey)
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Also effort on endcap and preshower is towards completion
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What should be done this year
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We have a solid base to start from but
refinement/completion work is needed in many areas
Primary goal: deliver a full coherent picture for
calibration/corrections
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Integration/use of the different calibration methods
Integration with the laser monitoring
Estimation of corrections using the data
Make it robust against real data problems (dead-channels...)
Detailed definition of the workflow from raw data to calibrations
propagated to the condition DB
Other important tasks
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Procedure to measure the tracker material budget. Whose job? Does
it need a joint task force ECAL + Tracker?
Paolo Meridiani - INFN Roma1
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Immediate Tasks
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Deliver a complete task list and identify where there is lack of
manpower
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Complete the parameterized geometry
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Put in the EE electronics mapping
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Define/choose a selective readout algorithm for low luminosities
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Speed optimized Raw to Digi unpacking
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and Digi to Raw code
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Implement a standard dead channel ‘energy estimate’ for RecHits
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Complete the development of the infrastructure needed for the laser
corrections
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MC truth tools
Paolo Meridiani - INFN Roma1
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