SSD hit reconstruction SCF SCM SCE
The reconstruction of the SSD hits is performed in two steps implemented in two different modules.

The first module SSD Cluster Finder (SCF) scans the strip signals on both sides of each SSD wafer in order to build clusters. This module :

These steps are schematically described here. A detailed description of the module can be found here.

The second step is performed by the SSD Cluster Matcher (SCM) module with two main goals : to associate the clusters found on the sides of each wafer and to determine the main parameters (position,energy loss) of the resulting space point.

Silicon microstrip wafers are not real bidimentional detectors and consequently clusters found on the n-side and the p-side of the detector need to be correlated based on some criteria. Depending on the particle multiplicity and their positions in the wafer, such correlation can be non trivial and can lead to ambiguous associations. Hopefully, for a given particle, the charges collected on both sides of the wafer are produced by the same energy deposite and a strategy based on a charge matching can be applied to help to correctly select the true associations.

Depending on the number of clusters on each side (latter on referenced as "packages") involved in this association problem, several configurations can be encountered. They are listed here and the cases 1, 1-2, 2-2, 2-3 and 3-3 are illustrated.

The following steps are performed in the module :

The list of tables used and methods defined in SCM to perform these steps can be found here. An example of how the geometrical correspondance is applied and how the packages are found is illustrated here. Solutions to apply the charge matching and to assign relative probabilities are shown for the cases 2-2 and 2-3.

The performances of the hit reconstruction modules will be evaluated with the help of the SSD Cluster Evaluator (SCE) module. The impact of their efficiencies on the tracking performance will be also studied. This module still needs to be written.

Last modified: Wed Jan 19 16:57:07 MET