[ALICE3] Magnet: add WindingPack (NbTi+Cu+Al) coil material option

Author: joseesquivel-hub

Detectors/MUON/MID/Simulation/src/Geometry.cxx

@@ -26,7 +26,6 @@
 #include <TGeoManager.h>
 #include <TGeoShape.h>
 #include <TGeoCompositeShape.h>
-#include <TGeoTube.h>
 
 namespace o2
 {
@@ -345,124 +344,10 @@ TGeoVolume* createChamber(int iChamber)
   return chamber;
 }
 
-/// Magnet geometry variant selector
-enum class MagnetVariant {
-  AluminiumWalls, ///< 11 cm cryostat, Al inner/outer walls
-  SteelWalls      ///< 10 cm cryostat, Fe inner/outer walls
-};
-
-/// Creates the MID magnet/cryostat geometry
-/// Port of GEANT4 simulation by Ian Perez Garcia (ICN-UNAM)
-/// Reference: github.com/IanPG/MID-Geometry-Studies
-void createMagnetGeometry(TGeoVolume& topVolume,
-                          MagnetVariant variant = MagnetVariant::AluminiumWalls)
-{
-  const float R_cryostat_inner = 140.0f;
-  const float R_cryostat_outer = 200.0f;
-  const float R_coil_inner = 160.0f;
-  const float magnetHalfLength = 400.0f;
-
-  const float thick_actual_coil = 4.8f;
-  const float thick_mli = 0.2f;
-  const float thick_coil_support = 2.0f;
-
-  float thick_inner_wall;
-  float thick_outer_wall;
-  int wallMedium;
-  const char* variantTag;
-
-  if (variant == MagnetVariant::AluminiumWalls) {
-    thick_inner_wall = 2.5f;
-    thick_outer_wall = 1.5f;
-    wallMedium = Medium::Aluminium;
-    variantTag = "Al";
-  } else {
-    thick_inner_wall = 1.5f;
-    thick_outer_wall = 1.5f;
-    wallMedium = Medium::Iron;
-    variantTag = "Steel";
-  }
-
-  const float R_inner_wall_outer = R_cryostat_inner + thick_inner_wall;
-  const float R_coil_outer = R_coil_inner + thick_actual_coil;
-  const float R_mli_inner = R_coil_outer;
-  const float R_mli_outer = R_mli_inner + thick_mli;
-  const float R_coil_support_inner = R_mli_outer;
-  const float R_coil_support_outer = R_coil_support_inner + thick_coil_support;
-  const float R_outer_wall_inner = R_cryostat_outer - thick_outer_wall;
-
-  // Mother volume (contains all cryostat layers)
-  auto magnetMotherShape = new TGeoTube(Form("MIDMagnetMother_%s_S", variantTag),
-                                        R_cryostat_inner, R_cryostat_outer, magnetHalfLength);
-  auto magnetMotherVol = new TGeoVolume(Form("MIDMagnetMother_%s", variantTag),
-                                        magnetMotherShape, assertMedium(Medium::Vacuum));
-  magnetMotherVol->SetVisibility(kFALSE);
-  topVolume.AddNode(magnetMotherVol, 1, new TGeoTranslation(0., 0., -1155.));
-
-  // Layer 1: Inner wall (Al or Fe)
-  auto innerWallVol = new TGeoVolume(Form("MIDInnerWall_%s", variantTag),
-                                     new TGeoTube(Form("MIDInnerWall_%s_S", variantTag),
-                                                  R_cryostat_inner, R_inner_wall_outer, magnetHalfLength),
-                                     assertMedium(wallMedium));
-  innerWallVol->SetLineColor((variant == MagnetVariant::AluminiumWalls) ? kCyan + 1 : kRed + 1);
-  magnetMotherVol->AddNode(innerWallVol, 1, nullptr);
-
-  // Layer 2: Inner vacuum gap
-  auto vacGap1Vol = new TGeoVolume(Form("MIDVacGap1_%s", variantTag),
-                                   new TGeoTube(Form("MIDVacGap1_%s_S", variantTag),
-                                                R_inner_wall_outer, R_coil_inner, magnetHalfLength),
-                                   assertMedium(Medium::Vacuum));
-  magnetMotherVol->AddNode(vacGap1Vol, 1, nullptr);
-
-  // Layer 3: Winding Pack (NbTi+Cu+Al, density=2.96 g/cm3)
-  auto coilVol = new TGeoVolume(Form("MIDCoil_%s", variantTag),
-                                new TGeoTube(Form("MIDCoil_%s_S", variantTag),
-                                             R_coil_inner, R_coil_outer, magnetHalfLength),
-                                assertMedium(Medium::WindingPack));
-  coilVol->SetLineColor(kRed);
-  magnetMotherVol->AddNode(coilVol, 1, nullptr);
-
-  // Layer 4: MLI - Multi-Layer Insulation (2mm Al)
-  auto mliVol = new TGeoVolume(Form("MIDMLI_%s", variantTag),
-                               new TGeoTube(Form("MIDMLI_%s_S", variantTag),
-                                            R_mli_inner, R_mli_outer, magnetHalfLength),
-                               assertMedium(Medium::Aluminium));
-  mliVol->SetLineColor(kYellow);
-  magnetMotherVol->AddNode(mliVol, 1, nullptr);
-
-  // Layer 5: A-5083 Support cylinder (20mm Al)
-  auto supportVol = new TGeoVolume(Form("MIDCoilSupport_%s", variantTag),
-                                   new TGeoTube(Form("MIDCoilSupport_%s_S", variantTag),
-                                                R_coil_support_inner, R_coil_support_outer, magnetHalfLength),
-                                   assertMedium(Medium::Aluminium));
-  supportVol->SetLineColor(kBlue - 7);
-  magnetMotherVol->AddNode(supportVol, 1, nullptr);
-
-  // Layer 6: Outer vacuum gap
-  auto vacGap2Vol = new TGeoVolume(Form("MIDVacGap2_%s", variantTag),
-                                   new TGeoTube(Form("MIDVacGap2_%s_S", variantTag),
-                                                R_coil_support_outer, R_outer_wall_inner, magnetHalfLength),
-                                   assertMedium(Medium::Vacuum));
-  magnetMotherVol->AddNode(vacGap2Vol, 1, nullptr);
-
-  // Layer 7: Outer wall (Al or Fe)
-  auto outerWallVol = new TGeoVolume(Form("MIDOuterWall_%s", variantTag),
-                                     new TGeoTube(Form("MIDOuterWall_%s_S", variantTag),
-                                                  R_outer_wall_inner, R_cryostat_outer, magnetHalfLength),
-                                     assertMedium(wallMedium));
-  outerWallVol->SetLineColor((variant == MagnetVariant::AluminiumWalls) ? kCyan + 1 : kRed + 1);
-  magnetMotherVol->AddNode(outerWallVol, 1, nullptr);
-}
-
 void createGeometry(TGeoVolume& topVolume)
 {
   createMaterials();
 
-  // Add magnet/cryostat geometry (Francisco Esquivel, June 2026)
-  printf("[MID] Calling createMagnetGeometry...\n");
-  createMagnetGeometry(topVolume, MagnetVariant::AluminiumWalls);
-  printf("[MID] createMagnetGeometry done. Top volume nodes: %d\n", topVolume.GetNdaughters());
-
   // create and place the trigger chambers
   for (int iCh = 0; iCh < detparams::NChambers; iCh++) {
 

Detectors/MUON/MID/Simulation/src/Materials.cxx

@@ -169,34 +169,6 @@ void createMaterials()
   mgr.Mixture(kModuleName, ++imat, "Nomex", aNomex, zNomex, dNomex, -nNomex, wNomex);
   mgr.Medium(kModuleName, Medium::Nomex, "Nomex", imat, 0, fieldType, maxField, kMaxfd, kStemax,
              kDeemax, kEpsil, kStmin);
-  /// Iron (pure Fe) - absorber and steel cryostat walls
-  /// G4 equivalent: G4_Fe, density = 7.874 g/cm3
-  const float kZIron_pure = 26.;
-  const float kAIron_pure = 55.845;
-  const float kDensIron = 7.874;
-  mgr.Material(kModuleName, ++imat, "Iron", kAIron_pure, kZIron_pure, kDensIron, 0., 0.);
-  mgr.Medium(kModuleName, Medium::Iron, "Iron", imat, 0, fieldType, maxField,
-             kMaxfd, kStemax, kDeemax, kEpsil, kStmin);
-
-  /// WindingPack - superconducting coil (NbTi + Cu + Al)
-  /// Mass fractions: NbTi=8.10%, Cu=11.18%, Al=80.72%, density=2.96 g/cm3
-  const float kZNiobium = 41.;
-  const float kANiobium = 92.90638;
-  const float kZTitanium = 22.;
-  const float kATitanium = 47.867;
-  const int nWP = 4;
-  float aWP[nWP] = {kANiobium, kATitanium, kACopper, kAAluminium};
-  float zWP[nWP] = {kZNiobium, kZTitanium, kZCopper, kZAluminium};
-  float wWP[nWP] = {0.0405, 0.0405, 0.1118, 0.8072};
-  float dWP = 2.96;
-  mgr.Mixture(kModuleName, ++imat, "WindingPack", aWP, zWP, dWP, nWP, wWP);
-  mgr.Medium(kModuleName, Medium::WindingPack, "WindingPack", imat, 0, fieldType, maxField,
-             kMaxfd, kStemax, kDeemax, kEpsil, kStmin);
-
-  /// Vacuum - thermal insulation gaps inside cryostat
-  mgr.Material(kModuleName, ++imat, "Vacuum", 1e-16, 1e-16, 1e-16, 0., 0.);
-  mgr.Medium(kModuleName, Medium::Vacuum, "Vacuum", imat, 0, fieldType, maxField,
-             kMaxfd, kStemax, kDeemax, kEpsil, kStmin);
 }
 
 TGeoMedium* assertMedium(int imed)

Detectors/MUON/MID/Simulation/src/Materials.h

@@ -33,10 +33,7 @@ enum Medium {
   Copper,
   Mylar,
   Styrofoam,
-  Nomex,
-  Iron,
-  WindingPack,
-  Vacuum
+  Nomex
 };
 
 // Return a pointer to the mid medium number imed.

Detectors/Upgrades/ALICE3/MID/simulation/src/Detector.cxx

@@ -86,26 +86,6 @@ void Detector::createMaterials()
 
   o2::base::Detector::Mixture(1, "POLYSTYRENE", aPolys, zPolys, dPolys, 2, wPolys);
   o2::base::Detector::Medium(1, "POLYSTYRENE", 1, 0, ifield, fieldm, tmaxfdPolys, stemaxPolys, deemaxPolys, epsilPolys, stminPolys);
-
-  // Iron (pure Fe) - cryostat walls (Steel variant)
-  float aIron = 55.845;
-  float zIron = 26.;
-  float dIron = 7.874;
-  o2::base::Detector::Material(2, "IRON", aIron, zIron, dIron, 0., 0.);
-  o2::base::Detector::Medium(2, "IRON", 2, 0, ifield, fieldm, tmaxfdPolys, stemaxPolys, deemaxPolys, epsilPolys, stminPolys);
-
-  // WindingPack - superconducting coil (NbTi + Cu + Al)
-  // Mass fractions: NbTi=8.10%, Cu=11.18%, Al=80.72%, density=2.96 g/cm3 (Arnaud report v0.2)
-  float aWP[4] = {92.90638, 47.867, 63.546, 26.982};
-  float zWP[4] = {41., 22., 29., 13.};
-  float wWP[4] = {0.0405, 0.0405, 0.1118, 0.8072};
-  float dWP = 2.96;
-  o2::base::Detector::Mixture(3, "WINDINGPACK", aWP, zWP, dWP, 4, wWP);
-  o2::base::Detector::Medium(3, "WINDINGPACK", 3, 0, ifield, fieldm, tmaxfdPolys, stemaxPolys, deemaxPolys, epsilPolys, stminPolys);
-
-  // Vacuum - thermal insulation gaps
-  o2::base::Detector::Material(4, "VACUUM", 1e-16, 1e-16, 1e-16, 0., 0.);
-  o2::base::Detector::Medium(4, "VACUUM", 4, 0, ifield, fieldm, tmaxfdPolys, stemaxPolys, deemaxPolys, epsilPolys, stminPolys);
 }
 
 void Detector::InitializeO2Detector()
@@ -160,46 +140,6 @@ void Detector::createGeometry()
   for (auto& layer : mLayers) {
     layer.createLayer(vMID);
   }
-
-  // Superconducting magnet/cryostat geometry
-  // Port of GEANT4 simulation by Ian Perez Garcia (ICN-UNAM)
-  // Reference: github.com/IanPG/MID-Geometry-Studies
-  // Aluminium walls variant: 11 cm total, Rmin=140 cm, Rmax=200 cm, half-length=400 cm
-  const float kRmin = 140.0f;
-  const float kRmax = 200.0f;
-  const float kHalfLen = 400.0f;
-  const float kWallInner = 2.5f;
-  const float kWallOuter = 1.5f;
-  const float kCoilInner = 160.0f;
-  const float kCoilThick = 4.8f;
-  const float kMLI = 0.2f;
-  const float kSupport = 2.0f;
-
-  const float kR1 = kRmin + kWallInner;
-  const float kR2 = kCoilInner;
-  const float kR3 = kCoilInner + kCoilThick;
-  const float kR4 = kR3 + kMLI;
-  const float kR5 = kR4 + kSupport;
-  const float kR6 = kRmax - kWallOuter;
-
-  auto* magnetMother = new TGeoVolume("MI3MagnetMother",
-                                      new TGeoTube("MI3MagnetMother_S", kRmin, kRmax, kHalfLen),
-                                      gGeoManager->GetMedium("MI3_POLYSTYRENE"));
-  gGeoManager->GetTopVolume()->AddNode(magnetMother, 1, new TGeoTranslation(0., 0., -1155.));
-
-  magnetMother->AddNode(new TGeoVolumeAssembly("MI3InnerWall"), 1, nullptr);
-
-  magnetMother->AddNode(new TGeoVolumeAssembly("MI3VacGap1"), 1, nullptr);
-
-  magnetMother->AddNode(new TGeoVolumeAssembly("MI3Coil"), 1, nullptr);
-
-  magnetMother->AddNode(new TGeoVolumeAssembly("MI3MLI"), 1, nullptr);
-
-  magnetMother->AddNode(new TGeoVolumeAssembly("MI3CoilSupport"), 1, nullptr);
-
-  magnetMother->AddNode(new TGeoVolumeAssembly("MI3VacGap2"), 1, nullptr);
-
-  magnetMother->AddNode(new TGeoVolumeAssembly("MI3OuterWall"), 1, nullptr);
 }
 
 void Detector::Reset()

Detectors/Upgrades/ALICE3/Passive/include/Alice3DetectorsPassive/PassiveBaseParam.h

@@ -26,7 +26,8 @@ namespace passive
 
 enum MagnetLayout : int {
   AluminiumStabilizer = 0,
-  CopperStabilizer = 1
+  CopperStabilizer = 1,
+  WindingPack = 2
 };
 
 enum DetLayout : int {

Detectors/Upgrades/ALICE3/Passive/src/Magnet.cxx

@@ -98,6 +98,16 @@ void Alice3Magnet::createMaterials()
   matmgr.Medium("ALICE3_MAGNET", 1, "VACUUM", 1, 0, isxfld, sxmgmx, tmaxfd, stemax, deemax, epsil, stmin);
   matmgr.Medium("ALICE3_MAGNET", 9, "ALUMINIUM", 9, 0, isxfld, sxmgmx, tmaxfd, stemax, deemax, epsil, stmin);
   matmgr.Medium("ALICE3_MAGNET", 19, "COPPER", 19, 0, isxfld, sxmgmx, tmaxfd, stemax, deemax, epsil, stmin);
+
+  // WindingPack: NbTi+Cu+Al composite (Arnaud report v0.2)
+  // Mass fractions: NbTi=8.10% (Nb=4.05%, Ti=4.05%), Cu=11.18%, Al=80.72%
+  // Density: 2.96 g/cm3
+  float aWP[4] = {92.90638f, 47.867f, 63.546f, 26.982f};
+  float zWP[4] = {41.f, 22.f, 29.f, 13.f};
+  float wWP[4] = {0.0405f, 0.0405f, 0.1118f, 0.8072f};
+  float dWP = 2.96f;
+  matmgr.Mixture("ALICE3_MAGNET", 29, "WINDINGPACK", aWP, zWP, dWP, 4, wWP);
+  matmgr.Medium("ALICE3_MAGNET", 29, "WINDINGPACK", 29, 0, isxfld, sxmgmx, tmaxfd, stemax, deemax, epsil, stmin);
 }
 
 void Alice3Magnet::ConstructGeometry()
@@ -128,6 +138,7 @@ void Alice3Magnet::ConstructGeometry()
   }
 
   bool doCopperStabilizer = false;
+  bool doWindingPack = false;
   switch (passiveBaseParam.mLayout) {
     case o2::passive::MagnetLayout::AluminiumStabilizer:
       // Handled in the header file
@@ -138,6 +149,10 @@ void Alice3Magnet::ConstructGeometry()
       mRestMaterialThickness += 2.2; // cm Add the Copper stabiliser
       LOG(debug) << "Alice 3 magnet: using Copper Stabilizer with thickness " << mRestMaterialThickness << " cm";
       break;
+    case o2::passive::MagnetLayout::WindingPack:
+      doWindingPack = true;
+      LOG(debug) << "Alice 3 magnet: using WindingPack (NbTi+Cu+Al) coil";
+      break;
     default:
       LOG(fatal) << "Unknown magnet layout " << passiveBaseParam.mLayout;
       break;
@@ -152,6 +167,7 @@ void Alice3Magnet::ConstructGeometry()
   auto& matmgr = o2::base::MaterialManager::Instance();
   auto kMedAl = matmgr.getTGeoMedium("ALICE3_MAGNET_ALUMINIUM");
   auto kMedCu = matmgr.getTGeoMedium("ALICE3_MAGNET_COPPER");
+  auto kMedWP = matmgr.getTGeoMedium("ALICE3_MAGNET_WINDINGPACK");
   auto kMedVac = matmgr.getTGeoMedium("ALICE3_MAGNET_VACUUM");
 
   // inner wrap
@@ -169,7 +185,7 @@ void Alice3Magnet::ConstructGeometry()
 
   TGeoVolume* innerWrapVol = new TGeoVolume("innerWrap", innerLayer, kMedAl);
   TGeoVolume* innerVacuumVol = new TGeoVolume("innerVacuum", innerVacuum, kMedVac);
-  TGeoVolume* coilsVol = new TGeoVolume("coils", coilsLayer, kMedCu);
+  TGeoVolume* coilsVol = new TGeoVolume("coils", coilsLayer, doWindingPack ? kMedWP : kMedCu);
   TGeoVolume* restMaterialVol = new TGeoVolume("restMaterial", restMaterial, doCopperStabilizer ? kMedCu : kMedAl);
   TGeoVolume* outerVacuumVol = new TGeoVolume("outerVacuum", outerVacuum, kMedVac);
   TGeoVolume* outerWrapVol = new TGeoVolume("outerWrap", outerLayer, kMedAl);