1. 1 Laser Monitoring: Offline Transparency Correction in CMSSW Toyoko Orimoto Caltech 13 July 2007

2. 2 Introduction CMS Gap Events FilterFarm/HLT Laser Farm Disk Buffer Online DB Offline DB Offline Reconstruction P5 Offline Tier0 CAF DAQ GT LASER ? Application of the transparency correction in the CMSSW framework, during the offline reconstruction, utilizing data (alphas, APD/PN reference, APD/PN) stored in the offline DB

3. 3 Ingredients for the Transparency Correction Under ideal conditions (ie, smooth transparency change, regular laser runs, no hardware problems): Linear interpolation between 2 APD/PN values (or nonlinear interpolation with 3) Need few APD/PN ratios (2 or 3?), time of the transparency measurement,  value, reference APD/PN value (all in Offline DB) x Physics Event Time Transparency Measurements Scale laser transparency change by constant  to match tall response change Interpolation Correction Factor Xtal response change under irradiation APD/PN Ref 20 min max. few %

4. 4 CMSSW Framework: EventSetup EventSetup (ES) system manages information with interval of validity (IOV) which may be different than the length of an event. Used for non-event data such as calibration, alignment, geometry, B field, etc ESSource: determines the IOV of a record.. In this case it will be the offline database which stores laser info (PoolDBESSource) ESProducer: algorithm which is run whenever there is IOV change for the record to which the producer is bound.  APD/PN ref APD/PN In the case of the laser system: time

5. 5 CalibCalorimetry/EcalLaserCorrection Development & testing in CMSSW_1_5_0 CalibCalorimetry/EcalLaserCorrection EcalLaserDbRecord: dependent record to hold EcalLaser DB records (EcalLaserAlphasRcd, EcalLaserAPDPNRatiosRefRcd, EcalLaserAPDPNRatiosRcd) EcalLaserDbService: serve as the referral to the DB record EcalLaserCorrectionService: ESProducer which will access the offline database, using EcalLaserDbRecord & EcalLaserDbService, and compute the transparency correction Will compute new correction with change in IOV for EcalLaserAPDPNRatios Return record of transparency correction to the Event Preliminary testing so far with empty source, using dummy numbers that Vladlen has put into the database. RecoLocalCalo/EcalRecAlgos & RecoLocalCalo/EcalRecProducers Where calibrated RecHits are actually produced

6. 6 One detail: Mapping of Light Monitoring Modules In Offline DB, store timestamps according to light monitoring modules, so we don’t have duplication of numbers In EB, straightforward correspondence between SM, DCC, and Light Monitoring Module. In EE, there are two monitoring regions which are read out by two DCCs.. (see picture) In total for the EB+EE: 54 DCCs, 88 LMs and 92 LM readout. So we propose this numbering scheme: Geometry/EcalMapping: deals with electronics mapping for ECAL One caveat: ECAL DQM numbers things from EE->EB->EB->EE DCCLM LM- readout EB-10-271-36 EB+28-4537-72 EE-1-973-8073-82 EE+46-5481-8883-92

7. 7 Next Steps Still in testing stages.. Will speak with some experts to make sure this class structure makes sense.. Based on Hcal calibration example as well as Ecal Intercalibration example Implement mapping between crystal and light monitoring modules