simple_detector.md: updating for dd4pod to edm4hep

src/docs/part1/simple_detector.md

@@ -152,11 +152,7 @@ Refer to the [GPS Documentation](https://geant4-userdoc.web.cern.ch/UsersGuides/
 
 ### Simulation output data model
 
-The geant4 output data model used by `npsim` is [described in a single yaml file](https://eicweb.phy.anl.gov/EIC/NPDet/-/blob/master/src/dd4pod/dd4hep.yaml).
-Note that this is purposefully factorized from the larger EIC data model, `eicd`, which is used 
-at every step post geant4.
-
-https://eic.phy.anl.gov/eicd/
+The geant4 output data model used by `npsim` is the EDM4hep data model, [described in a single yaml file](https://github.com/key4hep/EDM4hep/blob/master/edm4hep.yaml). This is also the data model used in evey step post geant4, complemented with the `eicd` data model [described in a single yaml file](https://eicweb.phy.anl.gov/EIC/eicd/-/blob/master/eic_data.yaml).
 
 
 ### Cell ID to position
@@ -188,10 +184,10 @@ Later on you can see its use while looping over hits:
 auto pos0 = h.position;
 auto pos1 = cellid_converter.position(h.cellID);
 ```
-Here `pos0` is a [dd4pod tracker hit](https://eic.phy.anl.gov/npdet/ref_doc/classdd4pod_1_1_tracker_hit.html) 
+Here `h` is a [EDM4hep SimTrackerHit](https://edm4hep.web.cern.ch/classedm4hep_1_1_sim_tracker_hit.html) 
 which has `position`, a 
-[dd4pod four vector](https://eic.phy.anl.gov/npdet/ref_doc/classdd4pod_1_1_four_vector.html). 
-This is the position (and time) of the Geant4 step through the sensitive tracking volume<sup>1</sup>. 
+[Vector3d vector](https://edm4hep.web.cern.ch/classedm4hep_1_1_vector3d.html). 
+This is the position of the Geant4 step through the sensitive tracking volume<sup>1</sup>. 
 
 `pos1` is a three vector of the smallest sensitive detector segment. 
 The converter tool is used along with the hit's `cellID` (i.e. unique channel number) to look up this position<sup>2</sup>.