From 38960532715c2f45abc7f62b5f8c4cd17b1a817c Mon Sep 17 00:00:00 2001
From: Gonzalo Martinez Lema <gonzaponte@gmail.com>
Date: Tue, 16 Apr 2024 17:49:56 +0200
Subject: [PATCH 01/13] Constrain EL_GAP generator to the PMT case

- Fix center in x,y to 0,0
- Fix diameter to el_gap diameter
- Rename el_gap_gen_disk_z{min,max} to el_gap_slice_{min,max}
---
 source/geometries/Next100FieldCage.cc | 105 ++++++++++----------------
 source/geometries/Next100FieldCage.h  |   7 +-
 2 files changed, 42 insertions(+), 70 deletions(-)

diff --git a/source/geometries/Next100FieldCage.cc b/source/geometries/Next100FieldCage.cc
index 1dad5e3bb..2aab21c2e 100644
--- a/source/geometries/Next100FieldCage.cc
+++ b/source/geometries/Next100FieldCage.cc
@@ -109,9 +109,7 @@ Next100FieldCage::Next100FieldCage(G4double grid_thickn):
   verbosity_(0),
   use_dielectric_grid_(0),
   // EL gap generation disk parameters
-  el_gap_gen_disk_diam_(0.),
-  el_gap_gen_disk_x_(0.), el_gap_gen_disk_y_(0.),
-  el_gap_gen_disk_zmin_(0.), el_gap_gen_disk_zmax_(1.),
+  el_gap_slice_min_(0.), el_gap_slice_max_(1.),
   photoe_prob_(0)
 {
   /// Define new categories
@@ -170,36 +168,19 @@ Next100FieldCage::Next100FieldCage(G4double grid_thickn):
   step_cmd.SetParameterName("max_step_size", true);
   step_cmd.SetRange("max_step_size>0.");
 
-  G4GenericMessenger::Command& el_gap_gen_disk_diam_cmd =
-    msg_->DeclareProperty("el_gap_gen_disk_diam", el_gap_gen_disk_diam_,
-                          "Diameter of the EL gap vertex generation disk.");
-  el_gap_gen_disk_diam_cmd.SetUnitCategory("Length");
-  el_gap_gen_disk_diam_cmd.SetParameterName("el_gap_gen_disk_diam", false);
-  el_gap_gen_disk_diam_cmd.SetRange("el_gap_gen_disk_diam>=0.");
-
-  G4GenericMessenger::Command& el_gap_gen_disk_x_cmd =
-    msg_->DeclareProperty("el_gap_gen_disk_x", el_gap_gen_disk_x_,
-                          "X position of the center of the EL gap vertex generation disk.");
-  el_gap_gen_disk_x_cmd.SetUnitCategory("Length");
-  el_gap_gen_disk_x_cmd.SetParameterName("el_gap_gen_disk_x", false);
-
-  G4GenericMessenger::Command& el_gap_gen_disk_y_cmd =
-    msg_->DeclareProperty("el_gap_gen_disk_y", el_gap_gen_disk_y_,
-                          "Y position of the center of the EL gap vertex generation disk.");
-  el_gap_gen_disk_y_cmd.SetUnitCategory("Length");
-  el_gap_gen_disk_y_cmd.SetParameterName("el_gap_gen_disk_y", false);
-
-  G4GenericMessenger::Command& el_gap_gen_disk_zmin_cmd =
-    msg_->DeclareProperty("el_gap_gen_disk_zmin", el_gap_gen_disk_zmin_,
-                          "Minimum Z range of the EL gap vertex generation disk.");
-  el_gap_gen_disk_zmin_cmd.SetParameterName("el_gap_gen_disk_zmin", false);
-  el_gap_gen_disk_zmin_cmd.SetRange("el_gap_gen_disk_zmin>=0.0 && el_gap_gen_disk_zmin<=1.0");
-
-  G4GenericMessenger::Command& el_gap_gen_disk_zmax_cmd =
-    msg_->DeclareProperty("el_gap_gen_disk_zmax", el_gap_gen_disk_zmax_,
-                          "Maximum Z range of the EL gap vertex generation disk.");
-  el_gap_gen_disk_zmax_cmd.SetParameterName("el_gap_gen_disk_zmax", false);
-  el_gap_gen_disk_zmax_cmd.SetRange("el_gap_gen_disk_zmax>=0.0 && el_gap_gen_disk_zmax<=1.0");
+  G4GenericMessenger::Command& el_gap_slice_min_cmd =
+    msg_->DeclareProperty("el_gap_slice_min", el_gap_slice_min_,
+                          "Lower limit (fraction) to the EL gap slice in which vertices are generated.");
+  el_gap_slice_min_cmd.SetParameterName("el_gap_slice_min", false);
+  el_gap_slice_min_cmd.SetRange("el_gap_slice_min >= 0.0 &&"
+                                "el_gap_slice_min <= 1.0");
+
+  G4GenericMessenger::Command& el_gap_slice_max_cmd =
+    msg_->DeclareProperty("el_gap_slice_max", el_gap_slice_max_,
+                          "Uppeer limit (fraction) to the EL gap slice in which vertices are generated.");
+  el_gap_slice_max_cmd.SetParameterName("el_gap_slice_max", false);
+  el_gap_slice_max_cmd.SetRange("el_gap_slice_max >= 0.0 &&"
+                                "el_gap_slice_max <= 1.0");
 
   msg_->DeclareProperty("photoe_prob", photoe_prob_,
                         "Probability of photon to ie- conversion");
@@ -420,7 +401,7 @@ void Next100FieldCage::BuildCathode()
   // Use SS hexagonal mesh
   else {
 
-      // Cathode Ring 
+      // Cathode Ring
       // Shift in the +z direction by half-mesh thickness and reduce thickness
       // by the grid thickness. The grid thickness makes up the remaining ring thickness
       cathode_solid =
@@ -433,13 +414,13 @@ void Next100FieldCage::BuildCathode()
       new G4PVPlacement(0, G4ThreeVector(GetCoordOrigin().x(), GetCoordOrigin().y(),
                                       cathode_zpos_ + grid_thickn_/2.0),
                       cathode_logic, "CATHODE_RING", mother_logic_, false, 0, false);
-      
+
       // Dist from centre of hex to hex vertex, excluding the land width (circumradius)
-      G4double hex_circumradius = cathode_mesh_diam_/std::sqrt(3);  
+      G4double hex_circumradius = cathode_mesh_diam_/std::sqrt(3);
 
       // Total number of hexagons that would fit side-by-side along the diameter
       G4int n_hex = (G4int) ((cathode_int_diam_/2.0) / hex_circumradius);
-    
+
       // Define the disk to punch hexagon holes through for the mesh
       G4Tubs* grid_solid = new G4Tubs("CATHODE_GRID", 0., cathode_ext_diam_/2.0 , grid_thickn_/2., 0., twopi);
       cathode_grid_logic = new G4LogicalVolume(grid_solid, steel_, "CATHODE_MESH_LOGIC");
@@ -675,15 +656,15 @@ void Next100FieldCage::BuildELRegion()
     el_gap_solid =
       new G4Tubs("EL_GAP", 0., gate_ext_diam_/2.,
                 (el_gap_length_ + 2*grid_thickn_)/2., 0, twopi);
-    
+
     // Meshes
 
     // Dist from centre of hex to hex vertex, excluding the land width (circumradius)
-    G4double hex_circumradius = el_mesh_diam_/std::sqrt(3)*mm;  
+    G4double hex_circumradius = el_mesh_diam_/std::sqrt(3)*mm;
 
     // Total number of hexagons that would fit side-by-side along the diameter
     G4int n_hex = (G4int) ((gate_int_diam_/2.0) / hex_circumradius);
-  
+
     // Define the disk to punch hexagon holes through for the mesh
     G4Tubs* grid_solid = new G4Tubs("EL_GRID", 0., gate_ext_diam_/2.0 , grid_thickn_/2., 0., twopi);
     el_grid_logic = new G4LogicalVolume(grid_solid, steel_, "EL_GRID");
@@ -691,7 +672,7 @@ void Next100FieldCage::BuildELRegion()
     // Define a hexagonal prism
     G4ExtrudedSolid* hex_prism = CreateHexagon(grid_thickn_/2.0, hex_circumradius);
     el_hex_logic  = new G4LogicalVolume(hex_prism, gas_, "MESH_HEX_GAS");
-   
+
     // Place GXe hexagons in the disk to make the mesh
     PlaceHexagons(n_hex, el_mesh_diam_, grid_thickn_, el_grid_logic, el_hex_logic, gate_int_diam_);
 
@@ -714,7 +695,7 @@ void Next100FieldCage::BuildELRegion()
 
   new G4PVPlacement(0, G4ThreeVector(0., 0., el_gap_zpos_),
                     el_gap_logic, "EL_GAP", mother_logic_, false, 0, false);
-  
+
   // Create a rotation vector to change the orientation of the EL mesh
   CLHEP::HepRotationZ Roty(el_mesh_rot_);
   G4RotationMatrix* pRot = new G4RotationMatrix();
@@ -722,11 +703,11 @@ void Next100FieldCage::BuildELRegion()
 
   new G4PVPlacement(0, G4ThreeVector(0., 0., el_gap_length_/2. + grid_thickn_/2.), el_grid_logic,
                     "EL_GRID_GATE", el_gap_logic, false, 0, false);
-  
+
   new G4PVPlacement(pRot, G4ThreeVector(0., 0., -el_gap_length_/2. - grid_thickn_/2.), el_grid_logic,
                     "EL_GRID_ANODE", el_gap_logic, false, 1, false);
 
-  
+
 
   /// Define EL electric field
   if (elfield_) {
@@ -744,24 +725,23 @@ void Next100FieldCage::BuildELRegion()
   }
 
   // Vertex generator
-  if (el_gap_gen_disk_zmin_ > el_gap_gen_disk_zmax_)
+  if (el_gap_slice_min_ > el_gap_slice_max_)
     G4Exception("[Next100FieldCage]", "Next100FieldCage()",
-                FatalErrorInArgument, "Error in configuration of EL gap generator: zmax < zmin");
-
-  G4double el_gap_gen_disk_thickn =
-    el_gap_length_ * (el_gap_gen_disk_zmax_ - el_gap_gen_disk_zmin_);
+                FatalErrorInArgument, "Error in configuration of EL gap generator: slice_max < slice_min");
 
-  G4double el_gap_gen_disk_z = el_gap_zpos_ + el_gap_length_/2.-
-                               el_gap_length_ * el_gap_gen_disk_zmin_ -
-                               el_gap_gen_disk_thickn/2.;
+  G4double el_gap_slice_thickness =
+    el_gap_length_ * (el_gap_slice_max_ - el_gap_slice_min_);
 
-  G4ThreeVector el_gap_gen_pos(el_gap_gen_disk_x_, el_gap_gen_disk_y_, el_gap_gen_disk_z);
+  G4double el_gap_slice_center = el_gap_zpos_ + el_gap_length_/2.   // start of el gap
+                               - el_gap_length_ * el_gap_slice_min_ // start of slice
+                               - el_gap_slice_thickness/2.;         // center of slice
 
   el_gap_gen_ =
-    new CylinderPointSampler(0., el_gap_gen_disk_diam_/2.,
-                             el_gap_gen_disk_thickn/2., 0., twopi,
-                             nullptr, el_gap_gen_pos);
-  
+    new CylinderPointSampler(0., gate_int_diam_/2.,
+                             el_gap_slice_thickness/2.,
+                             0., twopi,
+                             nullptr, {0, 0, el_gap_slice_center});
+
   // Gate ring vertex generator
   gate_gen_ =
     new CylinderPointSampler(gate_int_diam_/2., gate_ext_diam_/2.,
@@ -784,7 +764,7 @@ void Next100FieldCage::BuildELRegion()
 
   if (!grid_visibility_ && !use_dielectric_grid_)
     el_hex_logic->SetVisAttributes(G4VisAttributes::GetInvisible());
-  
+
   G4VisAttributes grey = nexus::DarkGrey();
   grey.SetForceSolid(true);
   gate_logic->SetVisAttributes(grey);
@@ -1128,14 +1108,7 @@ G4ThreeVector Next100FieldCage::GenerateVertex(const G4String& region) const
   }
 
   else if (region == "EL_GAP") {
-    G4VPhysicalVolume *VertexVolume;
-    do {
-      vertex = el_gap_gen_->GenerateVertex(VOLUME);
-      G4ThreeVector glob_vtx(vertex);
-      glob_vtx = glob_vtx - GetCoordOrigin();
-      VertexVolume =
-        geom_navigator_->LocateGlobalPointAndSetup(glob_vtx, 0, false);
-    } while (VertexVolume->GetName() != region);
+    vertex = el_gap_gen_->GenerateVertex(VOLUME);
   }
 
   else if (region == "FIELD_RING") {
diff --git a/source/geometries/Next100FieldCage.h b/source/geometries/Next100FieldCage.h
index c552b13fa..105c632cb 100644
--- a/source/geometries/Next100FieldCage.h
+++ b/source/geometries/Next100FieldCage.h
@@ -86,10 +86,9 @@ namespace nexus {
     // Use fake mesh
     G4bool use_dielectric_grid_;
 
-    // Parameters related to look-up table generation
-    G4double el_gap_gen_disk_diam_;
-    G4double el_gap_gen_disk_x_, el_gap_gen_disk_y_;
-    G4double el_gap_gen_disk_zmin_, el_gap_gen_disk_zmax_;
+    // Fraction of EL gap in which to generate points. e.g (0, 0.5)
+    // would generate points in the first half of the EL gap
+    G4double el_gap_slice_min_, el_gap_slice_max_;
 
     G4double active_length_, buffer_length_;
     G4double teflon_drift_length_, teflon_drift_zpos_,teflon_buffer_zpos_;

From 2468c07837c7344b4a43737eda3a258a15b26e06 Mon Sep 17 00:00:00 2001
From: Gonzalo Martinez Lema <gonzaponte@gmail.com>
Date: Tue, 16 Apr 2024 22:43:46 +0200
Subject: [PATCH 02/13] Rename el_gap_gen_ to el_gap_pmt_gen_

---
 source/geometries/Next100.cc              | 2 +-
 source/geometries/Next100FieldCage.cc     | 6 +++---
 source/geometries/Next100FieldCage.h      | 2 +-
 source/geometries/Next100InnerElements.cc | 2 +-
 4 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/source/geometries/Next100.cc b/source/geometries/Next100.cc
index 545b7618d..f6b25104b 100644
--- a/source/geometries/Next100.cc
+++ b/source/geometries/Next100.cc
@@ -243,7 +243,7 @@ namespace nexus {
              (region == "XENON") ||
              (region == "LIGHT_TUBE") ||
              (region == "HDPE_TUBE") ||
-             (region == "EL_GAP") ||
+             (region == "EL_GAP_PMT") ||
              (region == "EP_COPPER_PLATE") ||
              (region == "SAPPHIRE_WINDOW") ||
              (region == "OPTICAL_PAD") ||
diff --git a/source/geometries/Next100FieldCage.cc b/source/geometries/Next100FieldCage.cc
index 2aab21c2e..3f619c836 100644
--- a/source/geometries/Next100FieldCage.cc
+++ b/source/geometries/Next100FieldCage.cc
@@ -736,7 +736,7 @@ void Next100FieldCage::BuildELRegion()
                                - el_gap_length_ * el_gap_slice_min_ // start of slice
                                - el_gap_slice_thickness/2.;         // center of slice
 
-  el_gap_gen_ =
+  el_gap_pmt_gen_ =
     new CylinderPointSampler(0., gate_int_diam_/2.,
                              el_gap_slice_thickness/2.,
                              0., twopi,
@@ -1031,7 +1031,7 @@ Next100FieldCage::~Next100FieldCage()
   delete buffer_gen_;
   delete xenon_gen_;
   delete teflon_gen_;
-  delete el_gap_gen_;
+  delete el_gap_pmt_gen_;
   delete hdpe_gen_;
   delete ring_gen_;
   delete cathode_gen_;
@@ -1108,7 +1108,7 @@ G4ThreeVector Next100FieldCage::GenerateVertex(const G4String& region) const
   }
 
   else if (region == "EL_GAP") {
-    vertex = el_gap_gen_->GenerateVertex(VOLUME);
+    vertex = el_gap_pmt_gen_->GenerateVertex(VOLUME);
   }
 
   else if (region == "FIELD_RING") {
diff --git a/source/geometries/Next100FieldCage.h b/source/geometries/Next100FieldCage.h
index 105c632cb..9b3a08041 100644
--- a/source/geometries/Next100FieldCage.h
+++ b/source/geometries/Next100FieldCage.h
@@ -102,7 +102,7 @@ namespace nexus {
     CylinderPointSampler* buffer_gen_;
     CylinderPointSampler* teflon_gen_;
     CylinderPointSampler* xenon_gen_;
-    CylinderPointSampler* el_gap_gen_;
+    CylinderPointSampler* el_gap_pmt_gen_;
     CylinderPointSampler* hdpe_gen_;
     CylinderPointSampler* ring_gen_;
     CylinderPointSampler* cathode_gen_;
diff --git a/source/geometries/Next100InnerElements.cc b/source/geometries/Next100InnerElements.cc
index b03657b56..2210d2ad0 100644
--- a/source/geometries/Next100InnerElements.cc
+++ b/source/geometries/Next100InnerElements.cc
@@ -104,7 +104,7 @@ namespace nexus {
         (region == "CATHODE_RING") ||
         (region == "BUFFER") ||
         (region == "XENON")  ||
-        (region == "EL_GAP") ||
+        (region == "EL_GAP_PMT") ||
         (region == "LIGHT_TUBE") ||
         (region == "HDPE_TUBE") ||
         (region == "FIELD_RING") ||

From d9bfb5aa8757ac41fcd594494461e18c8b7e05e4 Mon Sep 17 00:00:00 2001
From: Gonzalo Martinez Lema <gonzaponte@gmail.com>
Date: Wed, 17 Apr 2024 11:39:21 +0200
Subject: [PATCH 03/13] Rename EL_GAP region to EL_GAP_PMT

---
 source/geometries/Next100FieldCage.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/source/geometries/Next100FieldCage.cc b/source/geometries/Next100FieldCage.cc
index 3f619c836..9a6992065 100644
--- a/source/geometries/Next100FieldCage.cc
+++ b/source/geometries/Next100FieldCage.cc
@@ -1107,7 +1107,7 @@ G4ThreeVector Next100FieldCage::GenerateVertex(const G4String& region) const
     vertex = hdpe_gen_->GenerateVertex(VOLUME);
   }
 
-  else if (region == "EL_GAP") {
+  else if (region == "EL_GAP_PMT") {
     vertex = el_gap_pmt_gen_->GenerateVertex(VOLUME);
   }
 

From 3166601682932edd14e382636e8e6987db2d4eb0 Mon Sep 17 00:00:00 2001
From: Gonzalo Martinez Lema <gonzaponte@gmail.com>
Date: Wed, 17 Apr 2024 11:40:22 +0200
Subject: [PATCH 04/13] Add generator for SiPM LT

---
 source/geometries/Next100.cc              |  1 +
 source/geometries/Next100FieldCage.cc     | 12 ++++++++++++
 source/geometries/Next100FieldCage.h      |  2 ++
 source/geometries/Next100InnerElements.cc |  1 +
 4 files changed, 16 insertions(+)

diff --git a/source/geometries/Next100.cc b/source/geometries/Next100.cc
index f6b25104b..abdcc41bf 100644
--- a/source/geometries/Next100.cc
+++ b/source/geometries/Next100.cc
@@ -244,6 +244,7 @@ namespace nexus {
              (region == "LIGHT_TUBE") ||
              (region == "HDPE_TUBE") ||
              (region == "EL_GAP_PMT") ||
+             (region == "EL_GAP_SIPM") ||
              (region == "EP_COPPER_PLATE") ||
              (region == "SAPPHIRE_WINDOW") ||
              (region == "OPTICAL_PAD") ||
diff --git a/source/geometries/Next100FieldCage.cc b/source/geometries/Next100FieldCage.cc
index 9a6992065..9ddcade6c 100644
--- a/source/geometries/Next100FieldCage.cc
+++ b/source/geometries/Next100FieldCage.cc
@@ -15,6 +15,7 @@
 #include "UniformElectricDriftField.h"
 #include "XenonProperties.h"
 #include "CylinderPointSampler.h"
+#include "BoxPointSampler.h"
 #include "HexagonMeshTools.h"
 
 #include <G4Navigator.hh>
@@ -742,6 +743,12 @@ void Next100FieldCage::BuildELRegion()
                              0., twopi,
                              nullptr, {0, 0, el_gap_slice_center});
 
+  auto sipm_pitch_ = 123;
+  auto unit_cell_center = G4ThreeVector{0, 0, el_gap_slice_center};
+  el_gap_sipm_gen_ =
+    new BoxPointSampler(sipm_pitch_/2, sipm_pitch_/2, el_gap_slice_thickness/2.,
+                        0, unit_cell_center, nullptr);
+
   // Gate ring vertex generator
   gate_gen_ =
     new CylinderPointSampler(gate_int_diam_/2., gate_ext_diam_/2.,
@@ -1032,6 +1039,7 @@ Next100FieldCage::~Next100FieldCage()
   delete xenon_gen_;
   delete teflon_gen_;
   delete el_gap_pmt_gen_;
+  delete el_gap_sipm_gen_;
   delete hdpe_gen_;
   delete ring_gen_;
   delete cathode_gen_;
@@ -1111,6 +1119,10 @@ G4ThreeVector Next100FieldCage::GenerateVertex(const G4String& region) const
     vertex = el_gap_pmt_gen_->GenerateVertex(VOLUME);
   }
 
+  else if (region == "EL_GAP_SIPM") {
+    vertex = el_gap_sipm_gen_->GenerateVertex(INSIDE);
+  }
+
   else if (region == "FIELD_RING") {
     G4VPhysicalVolume *VertexVolume;
     do {
diff --git a/source/geometries/Next100FieldCage.h b/source/geometries/Next100FieldCage.h
index 9b3a08041..4838d1c48 100644
--- a/source/geometries/Next100FieldCage.h
+++ b/source/geometries/Next100FieldCage.h
@@ -21,6 +21,7 @@ class G4Navigator;
 namespace nexus {
 
   class CylinderPointSampler;
+  class BoxPointSampler;
 
 
   class Next100FieldCage: public GeometryBase
@@ -103,6 +104,7 @@ namespace nexus {
     CylinderPointSampler* teflon_gen_;
     CylinderPointSampler* xenon_gen_;
     CylinderPointSampler* el_gap_pmt_gen_;
+    BoxPointSampler*      el_gap_sipm_gen_;
     CylinderPointSampler* hdpe_gen_;
     CylinderPointSampler* ring_gen_;
     CylinderPointSampler* cathode_gen_;
diff --git a/source/geometries/Next100InnerElements.cc b/source/geometries/Next100InnerElements.cc
index 2210d2ad0..810b5dbfc 100644
--- a/source/geometries/Next100InnerElements.cc
+++ b/source/geometries/Next100InnerElements.cc
@@ -105,6 +105,7 @@ namespace nexus {
         (region == "BUFFER") ||
         (region == "XENON")  ||
         (region == "EL_GAP_PMT") ||
+        (region == "EL_GAP_SIPM") ||
         (region == "LIGHT_TUBE") ||
         (region == "HDPE_TUBE") ||
         (region == "FIELD_RING") ||

From 47e4fdfc6d50c50ca81d205792f7470ab0462ecf Mon Sep 17 00:00:00 2001
From: Gonzalo Martinez Lema <gonzaponte@gmail.com>
Date: Wed, 17 Apr 2024 13:29:25 +0200
Subject: [PATCH 05/13] Propagate SiPM pitch information from SiPMBoard to
 FieldCage

---
 source/geometries/Next100FieldCage.cc     | 6 +++++-
 source/geometries/Next100FieldCage.h      | 8 ++++++++
 source/geometries/Next100InnerElements.cc | 1 +
 source/geometries/Next100SiPMBoard.h      | 4 ++++
 source/geometries/Next100TrackingPlane.cc | 5 +++++
 source/geometries/Next100TrackingPlane.h  | 1 +
 6 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/source/geometries/Next100FieldCage.cc b/source/geometries/Next100FieldCage.cc
index 9ddcade6c..68fc31b6e 100644
--- a/source/geometries/Next100FieldCage.cc
+++ b/source/geometries/Next100FieldCage.cc
@@ -111,6 +111,7 @@ Next100FieldCage::Next100FieldCage(G4double grid_thickn):
   use_dielectric_grid_(0),
   // EL gap generation disk parameters
   el_gap_slice_min_(0.), el_gap_slice_max_(1.),
+  sipm_pitch_(0),
   photoe_prob_(0)
 {
   /// Define new categories
@@ -743,7 +744,10 @@ void Next100FieldCage::BuildELRegion()
                              0., twopi,
                              nullptr, {0, 0, el_gap_slice_center});
 
-  auto sipm_pitch_ = 123;
+  if (sipm_pitch_ <= 0) {
+    G4Exception("[Next100FieldCage]", "Next100FieldCage()",
+                FatalErrorInArgument, "Error in configuration of EL gap generator: sipm_pitch <= 0");
+  }
   auto unit_cell_center = G4ThreeVector{0, 0, el_gap_slice_center};
   el_gap_sipm_gen_ =
     new BoxPointSampler(sipm_pitch_/2, sipm_pitch_/2, el_gap_slice_thickness/2.,
diff --git a/source/geometries/Next100FieldCage.h b/source/geometries/Next100FieldCage.h
index 4838d1c48..e964fe29a 100644
--- a/source/geometries/Next100FieldCage.h
+++ b/source/geometries/Next100FieldCage.h
@@ -37,6 +37,7 @@ namespace nexus {
     void SetMotherLogicalVolume(G4LogicalVolume* mother_logic);
     void SetMotherPhysicalVolume(G4VPhysicalVolume* mother_phys);
     void SetELtoSapphireWDWdistance(G4double);
+    void SetSiPMPitch(G4double);
 
   private:
     void DefineMaterials();
@@ -112,6 +113,9 @@ namespace nexus {
     CylinderPointSampler* anode_gen_;
     CylinderPointSampler* holder_gen_;
 
+    // SiPM pitch for ELgap vertex generation
+    G4double sipm_pitch_;
+
     // Geometry Navigator
     G4Navigator* geom_navigator_;
 
@@ -143,5 +147,9 @@ namespace nexus {
     gate_sapphire_wdw_dist_ = distance;
   }
 
+  inline void Next100FieldCage::SetSiPMPitch(G4double pitch) {
+    sipm_pitch_ = pitch;
+  }
+
 } //end namespace nexus
 #endif
diff --git a/source/geometries/Next100InnerElements.cc b/source/geometries/Next100InnerElements.cc
index 810b5dbfc..e80cbbb12 100644
--- a/source/geometries/Next100InnerElements.cc
+++ b/source/geometries/Next100InnerElements.cc
@@ -66,6 +66,7 @@ namespace nexus {
     field_cage_->SetMotherPhysicalVolume(mother_phys_);
     field_cage_->SetCoordOrigin(coord_origin);
     field_cage_->SetELtoSapphireWDWdistance(gate_sapphire_wdw_distance_);
+    field_cage_->SetSiPMPitch(tracking_plane_->GetSiPMPitch());
     field_cage_->Construct();
 
     // Energy Plane
diff --git a/source/geometries/Next100SiPMBoard.h b/source/geometries/Next100SiPMBoard.h
index ec2f1865c..1eac70d54 100644
--- a/source/geometries/Next100SiPMBoard.h
+++ b/source/geometries/Next100SiPMBoard.h
@@ -43,6 +43,7 @@ namespace nexus {
     G4double GetThickness() const;
 
     const std::vector<G4ThreeVector>& GetSiPMPositions() const;
+    G4double GetSiPMPitch() const;
 
   private:
     G4GenericMessenger* msg_;
@@ -68,6 +69,9 @@ namespace nexus {
   inline const std::vector<G4ThreeVector>& Next100SiPMBoard::GetSiPMPositions() const
   { return sipm_positions_; }
 
+  inline G4double Next100SiPMBoard::GetSiPMPitch() const
+  { return pitch_; }
+
 } // namespace nexus
 
 #endif
diff --git a/source/geometries/Next100TrackingPlane.cc b/source/geometries/Next100TrackingPlane.cc
index 68a212b7e..47d3d7746 100644
--- a/source/geometries/Next100TrackingPlane.cc
+++ b/source/geometries/Next100TrackingPlane.cc
@@ -244,3 +244,8 @@ G4ThreeVector Next100TrackingPlane::GenerateVertex(const G4String& region) const
 
   return vertex;
 }
+
+
+G4double Next100TrackingPlane::GetSiPMPitch() const {
+  return sipm_board_geom_->GetSiPMPitch();
+}
diff --git a/source/geometries/Next100TrackingPlane.h b/source/geometries/Next100TrackingPlane.h
index 8c0e8e826..f06a1dddb 100644
--- a/source/geometries/Next100TrackingPlane.h
+++ b/source/geometries/Next100TrackingPlane.h
@@ -42,6 +42,7 @@ namespace nexus {
 
     void PrintSiPMPosInGas() const;
     void GetSiPMPosInGas(std::vector<G4ThreeVector>& sipm_pos) const;
+    G4double GetSiPMPitch() const;
 
   private:
     void PlaceSiPMBoardColumns(G4int, G4double, G4double, G4int&, G4LogicalVolume*);

From 656bc4f16fa387dfd0512aff24e2c511ee28b686 Mon Sep 17 00:00:00 2001
From: Gonzalo Martinez Lema <gonzaponte@gmail.com>
Date: Wed, 17 Apr 2024 15:41:22 +0200
Subject: [PATCH 06/13] Add comments describing the behaviour of the EL_GAP
 generators

---
 source/geometries/Next100FieldCage.cc | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/source/geometries/Next100FieldCage.cc b/source/geometries/Next100FieldCage.cc
index 68fc31b6e..aae880aca 100644
--- a/source/geometries/Next100FieldCage.cc
+++ b/source/geometries/Next100FieldCage.cc
@@ -738,6 +738,8 @@ void Next100FieldCage::BuildELRegion()
                                - el_gap_length_ * el_gap_slice_min_ // start of slice
                                - el_gap_slice_thickness/2.;         // center of slice
 
+  // Here vertices are generated in a cylinder with the same diameter
+  // as the gate. In z, the vertices are limited to a slice of the EL gap.
   el_gap_pmt_gen_ =
     new CylinderPointSampler(0., gate_int_diam_/2.,
                              el_gap_slice_thickness/2.,
@@ -748,6 +750,14 @@ void Next100FieldCage::BuildELRegion()
     G4Exception("[Next100FieldCage]", "Next100FieldCage()",
                 FatalErrorInArgument, "Error in configuration of EL gap generator: sipm_pitch <= 0");
   }
+
+
+  // We generate vertices in an xy unit cell, i.e. a portion of the
+  // plane that can tessellate the space by translations and
+  // reflections. This unit cell is a square of side=pitch. The
+  // position of this is square is not relevant as long as it is
+  // sufficiently far away from the edges of the detector. The
+  // vertices are generated in a slice of the EL gap.
   auto unit_cell_center = G4ThreeVector{0, 0, el_gap_slice_center};
   el_gap_sipm_gen_ =
     new BoxPointSampler(sipm_pitch_/2, sipm_pitch_/2, el_gap_slice_thickness/2.,

From 4812ce7d92e42800b0a1752c06795fe108559e7e Mon Sep 17 00:00:00 2001
From: Gonzalo Martinez Lema <gonzaponte@gmail.com>
Date: Thu, 18 Apr 2024 12:50:34 +0200
Subject: [PATCH 07/13] Fix typo

---
 source/geometries/Next100FieldCage.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/source/geometries/Next100FieldCage.cc b/source/geometries/Next100FieldCage.cc
index aae880aca..f5ad4ad04 100644
--- a/source/geometries/Next100FieldCage.cc
+++ b/source/geometries/Next100FieldCage.cc
@@ -179,7 +179,7 @@ Next100FieldCage::Next100FieldCage(G4double grid_thickn):
 
   G4GenericMessenger::Command& el_gap_slice_max_cmd =
     msg_->DeclareProperty("el_gap_slice_max", el_gap_slice_max_,
-                          "Uppeer limit (fraction) to the EL gap slice in which vertices are generated.");
+                          "Upper limit (fraction) to the EL gap slice in which vertices are generated.");
   el_gap_slice_max_cmd.SetParameterName("el_gap_slice_max", false);
   el_gap_slice_max_cmd.SetRange("el_gap_slice_max >= 0.0 &&"
                                 "el_gap_slice_max <= 1.0");

From ccd6a56a5c2cfc9ea36307ce4a8408b7ea37fdb4 Mon Sep 17 00:00:00 2001
From: Gonzalo Martinez Lema <gonzaponte@gmail.com>
Date: Thu, 18 Apr 2024 12:52:53 +0200
Subject: [PATCH 08/13] Improve help strings

---
 source/geometries/Next100FieldCage.cc | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/source/geometries/Next100FieldCage.cc b/source/geometries/Next100FieldCage.cc
index f5ad4ad04..423ddfdd5 100644
--- a/source/geometries/Next100FieldCage.cc
+++ b/source/geometries/Next100FieldCage.cc
@@ -172,14 +172,18 @@ Next100FieldCage::Next100FieldCage(G4double grid_thickn):
 
   G4GenericMessenger::Command& el_gap_slice_min_cmd =
     msg_->DeclareProperty("el_gap_slice_min", el_gap_slice_min_,
-                          "Lower limit (fraction) to the EL gap slice in which vertices are generated.");
+                          "Lower limit (fraction of the whole length)"
+                          "to the EL gap slice in which vertices are generated."
+                          "0 is the gate, and 1 the anode");
   el_gap_slice_min_cmd.SetParameterName("el_gap_slice_min", false);
   el_gap_slice_min_cmd.SetRange("el_gap_slice_min >= 0.0 &&"
                                 "el_gap_slice_min <= 1.0");
 
   G4GenericMessenger::Command& el_gap_slice_max_cmd =
     msg_->DeclareProperty("el_gap_slice_max", el_gap_slice_max_,
-                          "Upper limit (fraction) to the EL gap slice in which vertices are generated.");
+                          "Upper limit (fraction of the whole length)"
+                          "to the EL gap slice in which vertices are generated."
+                          "0 is the gate, and 1 the anode");
   el_gap_slice_max_cmd.SetParameterName("el_gap_slice_max", false);
   el_gap_slice_max_cmd.SetRange("el_gap_slice_max >= 0.0 &&"
                                 "el_gap_slice_max <= 1.0");

From 27545add92c60ed8c9fe7c5b7f055c0ce24e9ebc Mon Sep 17 00:00:00 2001
From: Gonzalo Martinez Lema <gonzaponte@gmail.com>
Date: Thu, 18 Apr 2024 14:13:17 +0200
Subject: [PATCH 09/13] Rename generation regions

---
 source/geometries/Next100.cc              | 4 ++--
 source/geometries/Next100FieldCage.cc     | 4 ++--
 source/geometries/Next100InnerElements.cc | 4 ++--
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/source/geometries/Next100.cc b/source/geometries/Next100.cc
index abdcc41bf..908c6c141 100644
--- a/source/geometries/Next100.cc
+++ b/source/geometries/Next100.cc
@@ -243,8 +243,8 @@ namespace nexus {
              (region == "XENON") ||
              (region == "LIGHT_TUBE") ||
              (region == "HDPE_TUBE") ||
-             (region == "EL_GAP_PMT") ||
-             (region == "EL_GAP_SIPM") ||
+             (region == "S2_PMT_LT") ||
+             (region == "S2_SIPM_PSF") ||
              (region == "EP_COPPER_PLATE") ||
              (region == "SAPPHIRE_WINDOW") ||
              (region == "OPTICAL_PAD") ||
diff --git a/source/geometries/Next100FieldCage.cc b/source/geometries/Next100FieldCage.cc
index 423ddfdd5..94a334983 100644
--- a/source/geometries/Next100FieldCage.cc
+++ b/source/geometries/Next100FieldCage.cc
@@ -1133,11 +1133,11 @@ G4ThreeVector Next100FieldCage::GenerateVertex(const G4String& region) const
     vertex = hdpe_gen_->GenerateVertex(VOLUME);
   }
 
-  else if (region == "EL_GAP_PMT") {
+  else if (region == "S2_PMT_LT") {
     vertex = el_gap_pmt_gen_->GenerateVertex(VOLUME);
   }
 
-  else if (region == "EL_GAP_SIPM") {
+  else if (region == "S2_SIPM_PSF") {
     vertex = el_gap_sipm_gen_->GenerateVertex(INSIDE);
   }
 
diff --git a/source/geometries/Next100InnerElements.cc b/source/geometries/Next100InnerElements.cc
index e80cbbb12..78d510c1f 100644
--- a/source/geometries/Next100InnerElements.cc
+++ b/source/geometries/Next100InnerElements.cc
@@ -105,8 +105,8 @@ namespace nexus {
         (region == "CATHODE_RING") ||
         (region == "BUFFER") ||
         (region == "XENON")  ||
-        (region == "EL_GAP_PMT") ||
-        (region == "EL_GAP_SIPM") ||
+        (region == "S2_PMT_LT") ||
+        (region == "S2_SIPM_PSF") ||
         (region == "LIGHT_TUBE") ||
         (region == "HDPE_TUBE") ||
         (region == "FIELD_RING") ||

From 713ae6baa9eff6d95330fc3148712b8d67b0ac00 Mon Sep 17 00:00:00 2001
From: Gonzalo Martinez Lema <gonzaponte@gmail.com>
Date: Thu, 18 Apr 2024 15:40:21 +0200
Subject: [PATCH 10/13] Rename S1_table macros to S1_LT

---
 .../{NEXT100_S1_table.config.mac => NEXT100_S1_LT.config.mac} | 2 +-
 macros/{NEXT100_S1_table.init.mac => NEXT100_S1_LT.init.mac}  | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)
 rename macros/{NEXT100_S1_table.config.mac => NEXT100_S1_LT.config.mac} (94%)
 rename macros/{NEXT100_S1_table.init.mac => NEXT100_S1_LT.init.mac} (90%)

diff --git a/macros/NEXT100_S1_table.config.mac b/macros/NEXT100_S1_LT.config.mac
similarity index 94%
rename from macros/NEXT100_S1_table.config.mac
rename to macros/NEXT100_S1_LT.config.mac
index da8ae6db1..d86892646 100644
--- a/macros/NEXT100_S1_table.config.mac
+++ b/macros/NEXT100_S1_LT.config.mac
@@ -1,5 +1,5 @@
 ## ----------------------------------------------------------------------------
-## nexus | NEXT100_S1_table.config.mac
+## nexus | NEXT100_S1_LT.config.mac
 ##
 ## Configuration macro to simulate primary scintillation light
 ## for look-up tables in the NEXT-100 detector.
diff --git a/macros/NEXT100_S1_table.init.mac b/macros/NEXT100_S1_LT.init.mac
similarity index 90%
rename from macros/NEXT100_S1_table.init.mac
rename to macros/NEXT100_S1_LT.init.mac
index d6b1c5c12..d0a35930d 100644
--- a/macros/NEXT100_S1_table.init.mac
+++ b/macros/NEXT100_S1_LT.init.mac
@@ -1,5 +1,5 @@
 ## ----------------------------------------------------------------------------
-## nexus | NEXT100_S1_table.init.mac
+## nexus | NEXT100_S1_LT.init.mac
 ##
 ## Initialization macro to simulate primary scintillation light
 ## for look-up tables in the NEXT-100 detector.
@@ -23,4 +23,4 @@
 /nexus/RegisterTrackingAction DefaultTrackingAction
 /nexus/RegisterRunAction DefaultRunAction
 
-/nexus/RegisterMacro macros/NEXT100_S1_table.config.mac
+/nexus/RegisterMacro macros/NEXT100_S1_LT.config.mac

From 2b03362c222b5246b52630bdd766eb5563918a3b Mon Sep 17 00:00:00 2001
From: Gonzalo Martinez Lema <gonzaponte@gmail.com>
Date: Thu, 18 Apr 2024 15:40:35 +0200
Subject: [PATCH 11/13] Rename S2_table macros to S2_LT + adapt them to the new
 generator

---
 ...EXT100_S2_table.config.mac => NEXT100_S2_LT.config.mac} | 7 ++++---
 .../{NEXT100_S2_table.init.mac => NEXT100_S2_LT.init.mac}  | 4 ++--
 2 files changed, 6 insertions(+), 5 deletions(-)
 rename macros/{NEXT100_S2_table.config.mac => NEXT100_S2_LT.config.mac} (81%)
 rename macros/{NEXT100_S2_table.init.mac => NEXT100_S2_LT.init.mac} (88%)

diff --git a/macros/NEXT100_S2_table.config.mac b/macros/NEXT100_S2_LT.config.mac
similarity index 81%
rename from macros/NEXT100_S2_table.config.mac
rename to macros/NEXT100_S2_LT.config.mac
index 21ed3dd44..bc8a87b9d 100644
--- a/macros/NEXT100_S2_table.config.mac
+++ b/macros/NEXT100_S2_LT.config.mac
@@ -1,5 +1,5 @@
 ## ----------------------------------------------------------------------------
-## nexus | NEXT100_S2_table.config.mac
+## nexus | NEXT100_S2_LT.config.mac
 ##
 ## Configuration macro to simulate secondary scintillation light
 ## for look-up tables in the NEXT-100 detector.
@@ -20,11 +20,12 @@
 ##### GEOMETRY #####
 /Geometry/Next100/pressure 15. bar
 /Geometry/Next100/max_step_size 1. mm
-/Geometry/Next100/specific_vertex 0. 0. -5. mm
+/Geometry/Next100/el_gap_slice_max 1
+/Geometry/Next100/el_gap_slice_min 0
 
 #### GENERATOR ####
 /Generator/ScintGenerator/nphotons 100000
-/Generator/ScintGenerator/region   AD_HOC
+/Generator/ScintGenerator/region   S2_PMT_LT
 
 #### PERSISTENCY ####
 /nexus/persistency/output_file Next100_X_0_Y_0_Z_0.next
diff --git a/macros/NEXT100_S2_table.init.mac b/macros/NEXT100_S2_LT.init.mac
similarity index 88%
rename from macros/NEXT100_S2_table.init.mac
rename to macros/NEXT100_S2_LT.init.mac
index d7656c678..ec5562d6f 100644
--- a/macros/NEXT100_S2_table.init.mac
+++ b/macros/NEXT100_S2_LT.init.mac
@@ -1,5 +1,5 @@
 ## ----------------------------------------------------------------------------
-## nexus | NEXT100_S2_table.init.mac
+## nexus | NEXT100_S2_LT.init.mac
 ##
 ## Initialization macro to simulate secondary scintillation light
 ## for look-up tables in the NEXT-100 detector.
@@ -21,4 +21,4 @@
 /nexus/RegisterRunAction DefaultRunAction
 /nexus/RegisterTrackingAction DefaultTrackingAction
 
-/nexus/RegisterMacro macros/NEXT100_S2_table.config.mac
+/nexus/RegisterMacro macros/NEXT100_S2_LT.config.mac

From afb19a6f620daeb1cbfef10a524dded84c74f093 Mon Sep 17 00:00:00 2001
From: Gonzalo Martinez Lema <gonzaponte@gmail.com>
Date: Thu, 18 Apr 2024 15:41:03 +0200
Subject: [PATCH 12/13] Add S2_PSF macros

---
 macros/NEXT100_S2_PSF.config.mac | 31 +++++++++++++++++++++++++++++++
 macros/NEXT100_S2_PSF.init.mac   | 24 ++++++++++++++++++++++++
 2 files changed, 55 insertions(+)
 create mode 100644 macros/NEXT100_S2_PSF.config.mac
 create mode 100644 macros/NEXT100_S2_PSF.init.mac

diff --git a/macros/NEXT100_S2_PSF.config.mac b/macros/NEXT100_S2_PSF.config.mac
new file mode 100644
index 000000000..aa2fc082a
--- /dev/null
+++ b/macros/NEXT100_S2_PSF.config.mac
@@ -0,0 +1,31 @@
+## ----------------------------------------------------------------------------
+## nexus | NEXT100_S2_PSF.config.mac
+##
+## Configuration macro to simulate secondary scintillation light
+## for look-up tables in the NEXT-100 detector.
+##
+## The NEXT Collaboration
+## ----------------------------------------------------------------------------
+
+##### VERBOSITY #####
+/run/verbose 0
+/event/verbose 0
+/tracking/verbose 0
+
+/process/em/verbose 0
+
+##### JOB CONTROL #####
+/nexus/random_seed -2
+
+##### GEOMETRY #####
+/Geometry/Next100/pressure 15. bar
+/Geometry/Next100/max_step_size 1. mm
+/Geometry/Next100/el_gap_slice_max 1
+/Geometry/Next100/el_gap_slice_min 0
+
+#### GENERATOR ####
+/Generator/ScintGenerator/nphotons 100000
+/Generator/ScintGenerator/region   S2_SIPM_PSF
+
+#### PERSISTENCY ####
+/nexus/persistency/output_file Next100_PSF.next
diff --git a/macros/NEXT100_S2_PSF.init.mac b/macros/NEXT100_S2_PSF.init.mac
new file mode 100644
index 000000000..ed44da7b2
--- /dev/null
+++ b/macros/NEXT100_S2_PSF.init.mac
@@ -0,0 +1,24 @@
+## ----------------------------------------------------------------------------
+## nexus | NEXT100_S2_PSF.init.mac
+##
+## Initialization macro to simulate secondary scintillation light
+## for look-up tables in the NEXT-100 detector.
+##
+## The NEXT Collaboration
+## ----------------------------------------------------------------------------
+
+/PhysicsList/RegisterPhysics G4EmStandardPhysics_option4
+/PhysicsList/RegisterPhysics G4DecayPhysics
+/PhysicsList/RegisterPhysics G4OpticalPhysics
+/PhysicsList/RegisterPhysics NexusPhysics
+
+/nexus/RegisterGeometry Next100OpticalGeometry
+
+/nexus/RegisterGenerator ScintillationGenerator
+
+/nexus/RegisterPersistencyManager PersistencyManager
+
+/nexus/RegisterRunAction DefaultRunAction
+/nexus/RegisterTrackingAction DefaultTrackingAction
+
+/nexus/RegisterMacro macros/NEXT100_S2_PSF.config.mac

From 84e6a34f3b367f179a201e4434b18652ae78115b Mon Sep 17 00:00:00 2001
From: Gonzalo Martinez Lema <gonzaponte@gmail.com>
Date: Fri, 19 Apr 2024 10:10:01 +0200
Subject: [PATCH 13/13] Fix lu_table macro list in tests

---
 pytest/macros_test.py | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/pytest/macros_test.py b/pytest/macros_test.py
index f3413c50d..91656e5ff 100644
--- a/pytest/macros_test.py
+++ b/pytest/macros_test.py
@@ -33,8 +33,10 @@ def check_list(NEXUSDIR):
 def macro_list(NEXUSDIR):
 
     all_macros = np.array(glob.glob(NEXUSDIR + '/macros/**/*.init.mac', recursive=True))
-    full       = np.array(['full'  in m for m in all_macros])
-    lu_table   = np.array(['table' in m for m in all_macros])
+    full       = np.array(['full'  in m    for m in all_macros])
+    lu_table   = np.array(['table' in m or
+                           'LT'    in m or
+                           'PSF'   in m    for m in all_macros])
 
     full_macros = all_macros[  full | lu_table]
     fast_macros = all_macros[~(full | lu_table)]