Laser Monitoring: Offline Transparency Correction in CMSSW

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

2. DAQ GT Disk Buffer Laser Farm FilterFarm/HLT LASER Gap Events CMS Online DB P5 Offline Tier0 CAF Offline Reconstruction Offline DB ? Introduction 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. APD/PN Ref Physics Event Time Correction Factor Interpolation max. few % x Scale laser transparency change by constant to match tall response change Transparency Measurements 20 min Xtal response change under irradiation 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)

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 In the case of the laser system: APD/PN APD/PN ref a time • 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.

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. 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

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