A number of detectors have already been defined. To define your own, it is best to start with one of them and modify as necessary.
Full Detector Description
The detector geometry is defined using the compact format. The resulting lcdd file needs to be checked for overlaps.
The easiest way to do this is to create a macro file containing the following command
/geometry/test/recursive_test .
To check for overlaps:
> slic -g detector.lcdd -z -m geom_chk.mac
There may be a few spurious overlaps within calorimeters due to roundoff errors.
All other overlaps should be resolved.
Fast Monte Carlo Files
The current fast Monte Carlo smears charged tracks covariantly, and creates clusters for neutral particles, treating photons and neutral hadrons separately.
The fast Monte Carlo requires the following properties files to provide input:
TrackParameters.properties
The minimum transverse momentum as well as angular fiducial regions are defined here. The names of the track smearing files are also listed here. These files are generated using the lcdtrk program. These files should reside in the directory TrackParameters.
The file SimpleTrack provides the ability to define momentum smearing parameters independent of the lcdtrk parameters.
ClusterParameters.properties
This file contains the fiducial cuts on momentum and angular coverage as well as expected energy resolution terms for the electromagnetic and hadronic calorimeters. Electromagnetic and hadronic calorimeter resolution terms will be scaled to achieve the jet energy resolution specified by parameter JETResolution if the boolean parameter JETParameterization is set to true. To perform this scaling properly you must also specify the fraction of the jet energy that is electromagnetic (JETEMEnergyFraction) and the fraction due to neutral hadrons (JETHadEnergyFraction). You can choose to only scale the hadronic energy resolution (JETHadDegradeFraction=1), to only scale the electromagnetic resolution (JETHadDegradeFraction=0), or to scale both using an intermediate value for JETHadDegradeFraction. More information on the jet energy resolution algorithm can be found on pp. 162-163 of the SiD Detector Outline Document.
IDEfficiency.properties
This provides a simple method for simulating the confusion terms in identifying individual particles. In addition, the parameter wt_charged_track_calorimeter_energy determines how often a charged hadron's reconstructed energy will be set equal to the calorimeter energy. For example, if wt_charged_track_calorimeter_energy=0 then the tracker momentum will always be used for the charged hadron's reconstructed energy; if wt_charged_track_calorimeter_energy=1 then the calorimeter energy will always be used for the charged hadron's reconstructed energy.
SimpleTrack.properties
This file contains the parameters for smearing the transverse momentum p of charged tracks according to the simple formula ?p/p 2 = a + b/psin? . This method of smearing track parameters is
enabled by setting the MCFast class constructor argument simple=true. The file parameter ConstantTerm = a and the file parameter ThetaTerm = b . By default, the errors for the track angles and impact pararameters are taken from the files defined in TrackParameters.properties. However, the angle and impact parameter errors can be scaled relative to these default errors using the SimpleTrack.properties parameters TanLambdaErrorScale, PhiErrorScale, D0ErrorSCale and Z0ErrorScale.
Reconstruction Files
Calorimeter Sampling Fractions
Sampling fractions need to be provided for each calorimeter defined in the detector. Currently there needs to be one file for each calorimeter in the directory SamplingFractions, and there is currently only one value per calorimeter. This is clearly not correct for the electromagnetic calorimeters. (The values for the electromagnetic sampling fractions for the sid and cdc designs were obtained from 10GeV photons at theta of 25 and 90 degrees.) Sampling fractions for the hadron calorimeters are harder to define, especially for digital readout. Input is welcomed.