Change units to mm, and put in detector offset to center the coordinates.

benchmarks/far_forward/scripts/gen_far_forward_protons.cxx

@@ -21,8 +21,8 @@ void gen_far_forward_protons(int n_events = 100,
   double minMomentum = 270.0; //GeV
   double maxMomentum = 275.0; //GeV
   
-  double cos_theta_min = std::cos(0.0*(M_PI/180.0)); //we need MRAD for the units - syntax is degrees*Pi/180
-  double cos_theta_max = std::cos(0.2864789*(M_PI/180.0)); //1.15 degrees = 20mrad FF region is 0.0 to 20.0 mrad
+  double cos_theta_min = std::cos(0.0); //we need MRAD for the units - syntax is degrees*Pi/180
+  double cos_theta_max = std::cos(0.005); //1.15 degrees = 20mrad FF region is 0.0 to 20.0 mrad
 
   WriterAscii hepmc_output(out_fname);
   int events_parsed = 0;

benchmarks/far_forward/scripts/hits_far_forward_protons.cxx

@@ -19,6 +19,8 @@ R__LOAD_LIBRARY(libDD4pod.so)
 using ROOT::RDataFrame;
 using namespace ROOT::VecOps;
 
+double local_x_offset = -833.3878326;
+
 
 auto p_track = [](std::vector<eic::TrackParametersData> const& in) {
   std::vector<double> result;
@@ -93,7 +95,7 @@ auto local_position = [](const std::vector<dd4pod::TrackerHitData>& hits) {
       //auto pos1 = cellid_converter.position(h.cellID);
      
       //result.push_back({pos0.x / 10.0 - pos1.x(), pos0.y / 10.0 - pos1.y()});
-      result.push_back({pos0.x , pos0.y});
+      result.push_back({pos0.x - local_x_offset, pos0.y});
     }
     return result;
   };
@@ -146,7 +148,7 @@ int hits_far_forward_protons(const char* fname = "sim_far_forward_protons.root")
                  .Define("y_pos", y_pos, {"xy_hit_pos"})
                  ;
 
-  auto h_local_pos = df0.Histo2D({"h_local_pos", ";x [cm]; y [cm] ", 100, -1000.0, -700.0, 100, -8.0, 8.0}, "x_pos", "y_pos");
+  auto h_local_pos = df0.Histo2D({"h_local_pos", ";x [mm]; y [mm] ", 100, -150.0, 150.0, 100, -100.0, 100.0}, "x_pos", "y_pos");