...
Its single argument is the EventHeader of the current LCIO event. All collections in this event are accessible through the EventHeader interface.
We are interested in accessing the SimTrackerHits for the tracking detectors. We could use the method getSimTrackerHits(String name), but we choose not to in this example, since we do not, a priori, know the names of the collections in an arbitrary LCIO file.
Here is an example plot for a silicon strip barrel tracker layer:
Not too exiting, but now you know how to access tracker hits in the event.