For L6 the nominal radius corresponds to the outer one

Author: scannito

Detectors/Upgrades/ALICE3/TRK/simulation/include/TRKSimulation/TRKLayer.h

@@ -84,9 +84,9 @@ class TRKSegmentedLayer : public TRKCylindricalLayer
 
  protected:
   float mTiltAngle;
-
   int mNumberOfModules;
   int mNumberOfStaves;
+  bool mIsFlipped = false;
 
   // Fixed parameters for the layer, to be set based on the specifications of the chip and module
   static constexpr double sChipWidth = constants::moduleMLOT::chip::width;
@@ -122,6 +122,7 @@ class TRKMLLayer : public TRKSegmentedLayer
   float mStaggerOffset;
 
   static constexpr double sStaveWidth = constants::ML::width;
+  static constexpr int sFlippedLayerNumber = 3;
 
   // Override to account for the staggering offset present in specific ML layers
   std::pair<float, float> getBoundingRadii(double staveWidth) const override;

Detectors/Upgrades/ALICE3/TRK/simulation/src/TRKLayer.cxx

@@ -146,7 +146,7 @@ TGeoVolume* TRKSegmentedLayer::createChip()
   TGeoVolume* metalVol = createMetalStack();
   TGeoCombiTrans* transMetal = new TGeoCombiTrans();
 
-  if (mLayerNumber != nLayerToSwitchSens) {
+  if (!mIsFlipped) {
     transSens->SetTranslation(-sDeadzoneWidth / 2, (mChipThickness - sSensorThickness) / 2, 0);
     transDead->SetTranslation((sChipWidth - sDeadzoneWidth) / 2, (mChipThickness - sSensorThickness) / 2, 0);
     transMetal->SetTranslation(0, -sSensorThickness / 2, 0);
@@ -246,6 +246,12 @@ std::pair<float, float> TRKSegmentedLayer::getBoundingRadii(double staveWidth) c
 TRKMLLayer::TRKMLLayer(int layerNumber, std::string layerName, float rInn, float staggerOffset, float tiltAngle, int numberOfStaves, int numberOfModules, float thickOrX2X0, MatBudgetParamMode mode)
   : TRKSegmentedLayer(layerNumber, layerName, rInn, tiltAngle, numberOfStaves, numberOfModules, thickOrX2X0, mode), mStaggerOffset(staggerOffset)
 {
+  if (mLayerNumber == sFlippedLayerNumber) {
+    mOuterRadius = rInn;
+    mInnerRadius = rInn - mChipThickness;
+    mIsFlipped = true;
+    LOGP(info, "Layer {} is flipped: sensor and metal stack positions are switched", mLayerNumber);
+  }
 }
 
 TGeoVolume* TRKMLLayer::createStave()