CMS ECAL Status, Test Beams, Monitoring and Integration

DOE Review

Adi BornheimAdi BornheimCalifornia Institute of TechnologyCalifornia Institute of Technology

July 25, 2007July 25, 2007

CMS ECAL Status, Test Beams, CMS ECAL Status, Test Beams,

Monitoring and IntegrationMonitoring and Integration

July 25, 2007 A.Bornheim - DOE Review 2007 - CALTECH 2

Outline

ECAL Integration Status

Monitoring Project


CMS ECALLead-Tungstate Crystal Calorimeter~6.35 m

2.6 m

0.45 m 90 t of PbW04

~76000 Channels

Barrel segmented in 36 SuperModules (SM), each endcap in 2 Dee’s, endcap equipped with a Preshower detector.

Design resolution 0.5% above 100 GeV.

Dynamic range 0.04 GeV to >1000 GeV.

Very powerful detector for all lepton and photon base physics.

Crucial for H


Electronics Integration

All 36 SMs have been equipped with electronics and pre-calibrated with cosmic rays.

Very tight quality control. Spotted per-mille level problems which were fixed.

Tight schedule was kept with substantial help from the entire ECAL collaboration. Caltech students worked shifts for 4 months.

Y. YangECAL Integration Center


ECAL Insertion at LHC Point 5

One half of barrel ECAL (EB-) has been inserted into CMS in June. The second half is being inserted now (1 SM every 2 days). Expect to finish by the end of the week.

More than 99.9% of all channels are functioning perfectly.

Barrel ECAL will be cabled in September, to be fully integrated in global data taking soon after.

V. TimciucT. OrimotoECAL Insertion P5


CMS ECAL Endcap

Endcap assembly now in high gear. Dee’s are equipped with crystals, electronics, monitoring etc.

One third of all endcap crystals are at CERN; confident that all crystals will be delivered in time.

Goal is to insert both endcaps for physics running in 2008. Extensive test beam in 2007.

J. Veverka ECAL Endcap Monitoring Fibers


ECAL Preshower

Preshower EE

The Preshower assembly (part of the ECAL endcap) is now also getting on an accelerated schedule.

Testbeam 2007 with preshower, ECAL endcap and HCAL and possibly with endcap only for precision tests.

Caltech group is studying the preshower utilization. It is an integral part of ECAL which has yet to be brought to the same level of integration and understanding as the barrel ECAL.

Y. Ma


CMS ECAL Timeline

Insertion of last SMs is ongoing now.

Cabling of barrel ECAL done by September 2007.

Participation in CMS global runs starting October 2007.

Assembly and integration of Endcaps between now and March 2008.

Insertion of Endcaps shortly before closure of detector in 2008.

Preshower on a very similar time scale.

Start commissioning with physics data with the first collisions in 2008

Reach design performance in 2009.


All Supermodules have been pre-calibrated with cosmic rays with an average accuracy of 1.5%

Testbeam measurements and MC simulation agree at the level of 0.1%

ECAL Performance in the Test Beam

≤1% effect due to crystals “staircase” geometry predicted by simulation is measured in data with 1‰ accuracy

Comparison of inter-calibration coefficients obtained with the beam (Cbeam) and with cosmic rays (Ccosm)


Laser Monitoring Performance in Test Beam

Monitoring system has been operated at design specification during test beam 2006 for more than 1000 hours.

Transparency corrections have been studied and tested.

Caltech students have served several 100 hours of shifts in the test beam campaign 2006.

Monitoring stability

better than 0.1%

Restoring design resolution after

irradiation

C. Rogan


ECAL Crystals are radiation hard, but do change transparency under irradiation by several percent.

Measure transparency change every 20 minutes with a precision of better than 0.1 %.

Correct all physics data to ensure that the inter-calibration of all ECAL channels is not affected.

ECAL Laser Monitoring

Test Beam Data

Recovery RecoveryDamage DamageAPD

VPT


Laser Monitoring Project

In 2006 we processed all test beam data in quasi-online mode at CERN. Precision stability better 0.3% available within 15 minutes after data taking, better than 0.1% offline.

Since 2007 we are responsible for the entire ECAL monitoring project (jointly with Saclay) with Bornheim as the task leader.

Three students (Timciuc, Ma, Veverka) and Orimoto work on the monitoring project at CERN to fulfill their service requirements.

The project is now a task within the newly formed ECAL DPG group.


Laser Monitoring Workflow

CMS

Gap EventsFilterFarm/HLT Laser FarmDisk Buffer

Online DB

Offline DB

Offline Reconstruction

Online P5

OfflineTier0CAF

DAQ GT

LASER

Raw APD/PN

Corrected APD/PN

Repackage Laser Data

Y. Ma

V. Timciuc

J. Veverka

T. Orimoto

SaclayCALTECH

Saclay


Integration of Laser Source at P5

Time [s]

Las

er A

mp

litu

de

ECAL

CMSLaserSystem

Global Trigger

TTCciEMTC

Gap Events

Real Time Laser Trigger Sequence

Monitoring has to happen continuously during normal data taking.

Laser system and laser DAQ synchronized with LHC clock and CMS DAQ.

Monitoring data will be read during special calibration trigger and funneled into a dedicated stream.

Online processing of data to achieve fast feedback.

All hardware is commissioned and ready to go at P5.

Online Laser Data Processing Farm


Laser Monitoring: Online Data Flow

CMS Online DB

Offline DB


P5

OfflineTier0CAF

DAQ GT

LASERGap Events

FilterFarm/HLT Laser FarmDisk Buffer

Yousi Ma

Laser monitoring data will be acquired during LHC “gap” events. Gap events will arrive at the Filter Farm, containing, among other data, the ECAL laser event data.

One transparency measurement is based on a few hundred laser events on one light monitoring module. The ECAL laser data has to be extracted from the gap events and funneled into the CMSSW job running on the Laser Farm.

In particular, the data must be sorted into files containing all the laser events for one transparency measurement. This is being implemented in a standalone application by Y. Ma.


Laser Monitoring: Databases & Corrections

CMS

Gap EventsFilterFarm/HLT Disk Buffer


P5

OfflineTier0CAF

DAQ GT

LASER Laser Farm

OMDS

ORCON

ORCOFF

Once the laser data is sorted and processed to extract APD/PN values, this data must be inserted into the OMDS (the “online database”) located at Point 5.

The data must then be transferred using the online-to-offline (O2O) copy procedure, during which raw APD/PN ratios have to be normalized and corrected (eg. for the pulse width non-linearity).

The laser APD/PN ratios, reference values, and scale factors necessary to implement the transparency correction will be stored in the ORCON/ORCOFF “offline database”

V. Timciuc is currently developing software in the CMSSW framework for storing and transferring the data between databases, and J. Veverka will be joining him to work on the corrections

Vladlen TimciucJan Veverka

O2O


CMS

Gap EventsFilterFarm/HLT Disk Buffer

P5

OfflineTier0CAF

DAQ GT

LASER

ORCOFFOffline

Reconstruction

Laser Monitoring: Transparency Correction

The physics data has to be corrected for the effects of the crystal transparency change, and this will be done in the offline reconstruction.

For the correction, we will use the APD/PN ratios, reference values, and correction scale factors stored in the offline ORCOFF database.

The data will be interpolated in time in order to apply an accurate correction to physics events. The correction must be recalculated each time the interval of validity is updated.

We must develop a strategy to validate the laser transparency correction in-situ.

Currently working towards implementing the correction for CSA07.

Toyoko Orimoto


Monitoring Time Line to Physics Running

Participate in CSA07 with first offline transparency correction.

Participate in in CMS global runs with monitoring system starting in September 2007.

Implement and commission full monitoring scheme by early 2008.

Start routine running as soon as detector closed in 2008.

Start analysing data and tune performance as soon as beams circulate in LHC. Expected initial monitoring stability : ~0.3 %

Reach design performance for the monitoring 2008. Expected monitoring stability <0.1%.

Exercise synergies between monitoring effort and inter-calibration effort to maximize physics output of ECAL.


Summary

CALTECH is now in charge of the entire monitoring project.

ECAL integration is progressing smoothly. Expect to have a full ECAL available for physics data in 2008.

Extend our leadership further to ensure ECAL reaches design performance.

CMS ECAL Status, Test Beams, Monitoring and Integration

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