Update documentation

Update to a more detailed description in the VELO VP_tracking_monitors.py and VP_hit_efficiency.py

Hlt/RecoConf/options/examples/VP_hit_efficiency.py

@@ -15,8 +15,8 @@ from RecoConf.hlt1_tracking import (
     make_VeloClusterTrackingSIMD,
     make_reco_pvs,
     make_PatPV3DFuture_pvs,
-    get_global_measurement_provider,
     make_RetinaClusters,
+    get_global_measurement_provider,
     _rawevent_to_rawbank,
 )
 
@@ -42,9 +42,14 @@ from PyConf.Tools import (
 
 make_reco_pvs.global_bind(make_pvs_from_velo_tracks=make_PatPV3DFuture_pvs)
 """
-This file is an example of how to calculate the VELO hit efficiencies. 
-The algorithm uses tracks fitted by the TrackMasterFitter and only uses the LinearExtrapolator. Both in the interpolator and efficiency algorithm. 
-Due to the masking of the sensor_under_study, the track-fit has to be performed for each sensor separately. 
+Options file to determine the hit efficiencies in the VELO
+
+In the VPHitEfficiencyMonitor, the hit efficiency of sensors is determined and stored in an output ROOT file. Note: This is done independantly fromt the tracking efficiency.
+The VPHitEfficiencyMonitor will produce the hit efficiency per sensor. To cover the entire VELO, a loop over sensor_under_study is needed. To make sure the hit efficiencies 
+are not biassed, the sensor_under_study needs to be masked in tracking. Therefore, contrary to the options in VP_tracking_monitor.py, the tracking needs to be repeated for each sensor. 
+The tracks are fitted using the TrackMasterFitter and all extrapolators used are LinearExtrapolators. This includes the extrapolator used in the TrackInterpolator.
+As input for the VPHitEfficiencyMonitor, data is intended. To have 1 entry in all sensors requires on O(10^3) events at avg_mu=2.2. A more detailed map of the hit efficiencies,
+for instance to use in Boole, needs an order of events of ~O(10^10). (assuming 16x16 pixel bins)
 """
 
 
@@ -64,6 +69,7 @@ def make_my_sequence():
             my_SensorMask = [
                 sensor in [sensor_under_study] for sensor in range(208)
             ]
+
             vpClustering = VeloRetinaClusterTrackingSIMDFull(
                 RawBanks=_rawevent_to_rawbank(
                     default_raw_banks("VPRetinaCluster"), "VPRetinaCluster"),