ECAL Digitization in CMSSW Philosophy u Try to

ECAL Digitization in CMSSW: Philosophy u Try to reuse code as much as possible between systems u u ECAL, HCAL, Preshower? CASTOR? Keep things as simple as possible u Avoid big inheritance trees u Don’t get carried away with templates! u Tempting: Data. Frames & Det. Ids are specialized now u EBData. Frame, EEData. Frame u HBHEData. Frame, HOData. Frame, HFData. Frame u EBDet. Id, EEDet. Id, Hcal. Det. Id u Interface for changing conditions u Geometry u Pedestals & gains

ECAL Digitization in CMSSW Ecal. Sim. Producer Geometry Hits Conditions Calo. TDigitizer Digis Calo. Hit. Response Ecal. Coder Ecal. Sim. Parameter. Map Ecal. Pedestals

Calo. Hit. Response Adds up analog signals from Hits Same code for all subsystems è Input: r Calo Sim Hits r List of Active Det. Ids è Subdetector-specific parameters: r Shaping function r Hit correction, to do attenuation or delay r Some parameters (see next slide) è Output: r Analog signals (Calo. Samples)

Sim Parameter Maps Readout-cell-specific parameters, accessed by Det. Id (although in practice constant for all cells now) è Photomultiplier gain: r converts Sim. Hit energy to avg. # of photolectrons è Amp gain: r from photoelectrons to units of analog signal è Sampling factor r Fraction of incoming energy absorbed u 1 for ECAL, only relevant for HCAL è Timing phase adjustment è Readout frame size è Time bin of signal maximum è Whether or not to do Poisson photostatistics è Nominal calibration constant r Sampling factor / Photomultiplier gain / amp gain

ECAL Coder u Needs to know pedestals to use: è Producer can read them from conditions DB, if requested è Can use Shahram’s Conditions DB interface now u Why should simulation use real gains & pedestals? è Other experiments do è Makes for realism r Hot channels are hot r Noisy channels are noisy u Try to keep things simple è Producer fetches conditions, and passes to algorithms è Avoid software dependence on databases.

Status: u WORKING: è Running from files of CMSSW hits è Running combined G 4 + digitization jobs u To do: (along with experts) è Trigger Simulation è Selective Readout è Integrate with Shahram’s reconstruction