ITS3: fix longeron length to not clip into Hring

Signed-off-by: Felix Schlepper <felix.schlepper@cern.ch>

Author: f3sch

Detectors/Upgrades/ITS3/base/include/ITS3Base/SpecsV2.h

@@ -102,9 +102,9 @@ constexpr double lengthSensitive{nRSUs * rsu::length};
 namespace carbonfoam
 {
 // TODO: Waiting for the further information from WP5(Corrado)
-constexpr double longeronsWidth{2.0 * mm};                                 // what is the height of the longerons?
-constexpr double longeronsLength{263 * mm};                                // from blueprint
 constexpr double HringLength{6.0 * mm};                                    // from blueprint
+constexpr double longeronsWidth{2.0 * mm};                                 // what is the height of the longerons?
+constexpr double longeronsLength{segment::length - 2 * HringLength};       // 263mm from blueprint; overrriden to be consitent
 constexpr double edgeBetwChipAndFoam{1.0 * mm};                            // from blueprint but not used cause forms are already overlapping
 constexpr double gapBetwHringsLongerons{0.05 * mm};                        // from blueprint
 constexpr std::array<int, 3> nHoles{11, 11, 11};                           // how many holes for each layer?

Detectors/Upgrades/ITS3/simulation/src/ITS3Layer.cxx

@@ -312,8 +312,8 @@ void ITS3Layer::createCarbonForm()
   auto zMoveHringA = new TGeoTranslation(0, 0, -constants::segment::lec::length + HringLength / 2. + constants::segment::length - HringLength);
 
   // Longerons are made by same material
-  [[maybe_unused]] auto longeronR = new TGeoTubeSeg(Form("longeronR%d", mNLayer), mRmax, mRmax + dRadius, longeronsLength / 2, phiSta, phiSta + phiLongeronsCover);
-  [[maybe_unused]] auto longeronL = new TGeoTubeSeg(Form("longeronL%d", mNLayer), mRmax, mRmax + dRadius, longeronsLength / 2, phiEnd - phiLongeronsCover, phiEnd);
+  [[maybe_unused]] auto longeronR = new TGeoTubeSeg(Form("longeronR%d", mNLayer), mRmax, mRmax + dRadius, longeronsLength / 2., phiSta, phiSta + phiLongeronsCover);
+  [[maybe_unused]] auto longeronL = new TGeoTubeSeg(Form("longeronL%d", mNLayer), mRmax, mRmax + dRadius, longeronsLength / 2., phiEnd - phiLongeronsCover, phiEnd);
   TString nameLongerons = Form("longeronR%d + longeronL%d", mNLayer, mNLayer);
   auto longerons = new TGeoCompositeShape(nameLongerons);
   auto longeronsVol = new TGeoVolume(Form("longerons%d", mNLayer), longerons, mCarbon);