Geometry properties

Summarizing, sensors are stored in objects of classes that derive from a single, common base class -- TPhSensorSet. This makes it easy to write processing functions that take a TPhSensorSet object as parameter to define a geometric scope of processing operations. Sensors can be stored in many different sensor sets which makes possible to define multiple, user defined logical sets of sensors that are most convenient for the user from the point of view of particular application. A tree of predefined logical structures consisting of subdetectors, layers, planes and modules is created and stored together with sensor properties in the geometry file.

Both sensors and sensor sets are TNode type classes that derive from a common TPhSensorNode class. The geometrical parameters of all sensors are stored in the appropriate objects of classes that derive from a common class TShape. TPhSensorNode class provides basic geometrical and sorting operations . The geometrical transformations can be applied not only on a sensor by sensor level, but moving sensor sets, just as it happens in reality. The changes in a position of a sensor set are automatically propagated to all sensors (and their subsets) in the current sensor set.

More detailed description of classes and objects that the geometry in Phat is composed of can be found at

http://www.bnl.gov/phobos/~olszewski/Active\_geometry.html