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26 //
27 /// \file DetectorConstruction.cc
28 /// \brief DetectorConstruction class
29 //
30 //
31 #include "DetectorConstruction.hh"
32
33 #include "G4Box.hh"
34 #include "G4GeometryManager.hh"
35 #include "G4LogicalVolume.hh"
36 #include "G4Material.hh"
37 #include "G4NistManager.hh"
38 #include "G4PVPlacement.hh"
39 #include "G4ProductionCuts.hh"
40 #include "G4RunManager.hh"
41 #include "G4SystemOfUnits.hh"
42 #include "G4ThreeVector.hh"
43 #include "G4Tubs.hh"
44 #include "G4UnitsTable.hh"
45 #include "G4VPhysicalVolume.hh"
46 #include "G4VisAttributes.hh"
47
48 const bool check_intersections = true; // to control geometry for errors
49
50 // new unit
51 const G4double ug = 1.e-6 * g;
52
53 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
54
55 G4VPhysicalVolume* DetectorConstruction::Construct()
56 {
57 auto man = G4NistManager::Instance();
58
59 // registering new useful unit
60 new G4UnitDefinition("microgram", "ug", "Mass", ug);
61
62 // geometric parameters
63 G4double worldSize = 8 * cm;
64 G4double worldDensity = 0.15 * mg / m3; // imperfect vacuum as in a real-world experiment
65
66 G4double IV_diameter = 10 * mm;
67 G4double IV_height = 20 * mm;
68 G4double IV_vertical_offset = -5 * mm; // instead of moving beam axis, the IV is moved
69 G4double IV_density = 0.45 * ug / cm3;
70
71 G4double wall_tot_mass_thickness = 0.98 * mg / cm2; // Mylar wall thickness -> 7 µm
72 G4double wall_inner_layer_mass_thickness =
73 0.02 * mg / cm2; // inner layer of wall made of water material at Mylar density
74
75 fCollDiameter = 3 * mm; // inner diameter of the collimator, the outer is twice that
76 fCollLength = 23 * mm;
77 fCollExitPosition = -5.5 * mm; // exit of the collimator, where the beam is already formed
78
79 G4double enDet_diameter = 10 * mm;
80 G4double enDet_thickness = 150 * um;
81 G4double enDet_distance = 10 * mm;
82
83 // materials
84 auto worldMaterial =
85 man->BuildMaterialWithNewDensity("WORLD_WATER_VACUUM", "G4_WATER", worldDensity);
86 auto targetMaterial = man->BuildMaterialWithNewDensity("TARGET_WATER", "G4_WATER", IV_density);
87 auto wallMaterial = man->FindOrBuildMaterial("G4_MYLAR");
88 auto collMaterial = man->FindOrBuildMaterial("G4_BRASS");
89 auto enDetMaterial = man->FindOrBuildMaterial("G4_Si");
90
91 // auxiliary variables:
92 G4ThreeVector origin(0, 0, 0);
93 G4ThreeVector IV_centre(0, 0, IV_vertical_offset);
94 G4ThreeVector enDet_centre(enDet_distance + IV_diameter / 2., 0, 0);
95
96 G4double mylarDensity = wallMaterial->GetDensity();
97 G4double wall_total_thickness = wall_tot_mass_thickness / mylarDensity;
98 G4double wall_inner_layer_thickness = wall_inner_layer_mass_thickness / mylarDensity;
99
100 // materials continued
101 auto innerWallMaterial = man->BuildMaterialWithNewDensity("WALL_WATER", "G4_WATER", mylarDensity);
102
103 // SAVING DETECTOR SETTINGS TO FILE:
104 auto filename = "SIM_GEOMETRY_SETTINGS.txt";
105 std::ofstream TextFile;
106 TextFile.open(filename, std::fstream::out);
107 TextFile << "worldSize = " << worldSize / cm << " cm\n";
108 TextFile << "worldDensity = " << worldDensity / (mg / m3) << " mg/m3\n";
109 TextFile << "IV_diameter = " << IV_diameter / mm << " mm\n";
110 TextFile << "IV_height = " << IV_height / mm << " mm\n";
111 TextFile << "IV_vertical_offset = " << IV_vertical_offset / mm << " mm\n";
112 TextFile << "IV_density = " << IV_density / (ug / cm3) << " ug/cm3\n";
113 TextFile << "wall_tot_mass_thickness = " << wall_tot_mass_thickness / (mg / cm2) << " mg/cm2\n";
114 TextFile << "wall_inner_layer_mass_thickness = " << wall_inner_layer_mass_thickness / (mg / cm2)
115 << " mg/cm2\n";
116 TextFile << "fCollDiameter = " << fCollDiameter / mm << " mm\n";
117 TextFile << "fCollLength = " << fCollLength / mm << " mm\n";
118 TextFile << "fCollExitPosition = " << fCollExitPosition / mm << " mm\n";
119 TextFile << "enDet_diameter = " << enDet_diameter / mm << " mm\n";
120 TextFile << "enDet_thickness = " << enDet_thickness / mm << " mm\n";
121 TextFile << "enDet_distance = " << enDet_distance / mm << " mm\n";
122 TextFile << "worldMaterial: " << worldMaterial->GetName() << "\n";
123 TextFile << "targetMaterial: " << targetMaterial->GetName() << "\n";
124 TextFile << "wallMaterial: " << wallMaterial->GetName() << "\n";
125 TextFile << "collMaterial: " << collMaterial->GetName() << "\n";
126 TextFile << "enDetMaterial: " << enDetMaterial->GetName() << "\n";
127 TextFile << "innerWallMaterial: " << innerWallMaterial->GetName() << "\n";
128
129 // WORLD VOLUME
130
131 auto worldSolid = new G4Box("worldSolid", // its name
132 worldSize / 2, worldSize / 2,
133 worldSize / 2); // its size
134
135 auto worldLogic = new G4LogicalVolume(worldSolid, // its solid
136 worldMaterial, // its material
137 "worldLogic"); // its name
138
139 auto worldPhys = new G4PVPlacement(nullptr, // no rotation
140 G4ThreeVector(0, 0, 0), // placement
141 worldLogic, // its logical volume
142 "worldPhys", // its name
143 nullptr, // its mother volume
144 false, // no boolean operation
145 0, // copy number
146 check_intersections); // check intersections
147
148 // INTERACTION VOLUME (IV, also called chamber)
149 auto chamberSolid = new G4Tubs("chamberSolid", // its name
150 0, // rMin
151 IV_diameter / 2., // rMax
152 IV_height / 2., // height/2
153 0 * deg, // phiMin
154 360 * deg); // phiMax
155
156 auto chamberLogic = new G4LogicalVolume(chamberSolid, // its solid
157 targetMaterial, // its material
158 "chamberLogic"); // its name
159
160 new G4PVPlacement(nullptr, IV_centre, chamberLogic, "chamberPhys", worldLogic, false, 0,
161 check_intersections);
162
163 // SENSITIVE VOLUME (SV, also called target) - in general a sub-volume of the
164 // IV, but in this case entire IV is the SV only ionisations that occur in the
165 // SV will be counted
166 auto targetSolid = new G4Tubs("targetSolid", // name
167 0, // rMin
168 IV_diameter / 2., // rMax
169 IV_height / 2., // height/2
170 0 * deg, // phiMin
171 360 * deg); // phiMax
172
173 auto targetLogic = new G4LogicalVolume(targetSolid, targetMaterial, "targetLogic");
174
175 new G4PVPlacement(nullptr, origin, targetLogic, "targetPhys", chamberLogic, false, 0,
176 check_intersections);
177
178 // WALLS:
179 //
180
181 auto wallSolid = new G4Tubs("wallSolid", // name
182 IV_diameter / 2., // rMin
183 IV_diameter / 2. + wall_total_thickness, // rMax
184 IV_height / 2., // height/2
185 0 * deg, // phiMin
186 360 * deg); // phiMax
187
188 auto wallLogic = new G4LogicalVolume(wallSolid, wallMaterial, "wallSolid");
189 new G4PVPlacement(nullptr, IV_centre, wallLogic, "wallPhys", worldLogic, false, 0,
190 check_intersections);
191
192 // wall inner layer made of water
193 auto innerWallSolid = new G4Tubs("innerWallSolid", // name
194 IV_diameter / 2., // rMin
195 IV_diameter / 2. + wall_inner_layer_thickness, // rMax
196 IV_height / 2., // height/2
197 0 * deg, // phiMin
198 360 * deg); // phiMax
199
200 auto innerWallLogic = new G4LogicalVolume(innerWallSolid, innerWallMaterial, "innerWallLogic");
201 new G4PVPlacement(nullptr, origin, innerWallLogic, "innerWallPhys", wallLogic, false, 0,
202 check_intersections);
203
204 // COLLIMATOR:
205 auto collSolid = new G4Tubs("collSolid", // name
206 fCollDiameter / 2., // rMin
207 fCollDiameter, // rMax
208 fCollLength / 2., // height/2
209 0 * deg, // phiMin
210 360 * deg); // phiMax
211
212 auto collLogic = new G4LogicalVolume(collSolid, collMaterial, "collSolid");
213
214 auto rot = new G4RotationMatrix();
215 rot->rotateY(90 * deg);
216 new G4PVPlacement(rot, G4ThreeVector(-fCollLength / 2 + fCollExitPosition, 0, 0), collLogic,
217 "collPhys", worldLogic, false, 0, check_intersections);
218
219 // SILICON DETECTOR - present only in macrometric geometry
220
221 auto enDetSolid = new G4Tubs("enDetSolid", // name
222 0, // rMin
223 enDet_diameter / 2., // rMax
224 enDet_thickness / 2., // height/2
225 0 * deg, 360 * deg);
226
227 auto enDetLogic = new G4LogicalVolume(enDetSolid, enDetMaterial, "enDetLogic");
228 new G4PVPlacement(rot, enDet_centre, enDetLogic, "enDetPhys", worldLogic, false, 0,
229 check_intersections);
230
231 // VISUALISATION ATTRIBUTES
232
233 auto worldVisAtt = new G4VisAttributes(G4Colour(1, 1, 1, 0.1));
234 worldLogic->SetVisAttributes(worldVisAtt);
235
236 auto targetVisAtt = new G4VisAttributes(G4Colour(0.1, 0.5, 1, 0.7));
237 targetLogic->SetVisAttributes(targetVisAtt);
238
239 auto innerWallVisAtt = new G4VisAttributes(G4Colour(0, 1, 1, 0.7));
240 innerWallLogic->SetVisAttributes(innerWallVisAtt);
241
242 auto collVisAtt = new G4VisAttributes(G4Colour(0.7, 0.65, .25, 0.5));
243 collLogic->SetVisAttributes(collVisAtt);
244
245 auto enDetVisAtt = new G4VisAttributes(G4Colour(0.5, 0.7, .5, 1.));
246 enDetLogic->SetVisAttributes(enDetVisAtt);
247
248 // Create Target G4Region and add logical volume
249
250 auto region = new G4Region("Target");
251
252 auto cuts = new G4ProductionCuts();
253
254 G4double defCut = 1 * nanometer;
255 cuts->SetProductionCut(defCut, "gamma");
256 cuts->SetProductionCut(defCut, "e-");
257 cuts->SetProductionCut(defCut, "e+");
258 cuts->SetProductionCut(defCut, "proton");
259
260 region->SetProductionCuts(cuts);
261 region->AddRootLogicalVolume(chamberLogic);
262 region->AddRootLogicalVolume(targetLogic);
263 region->AddRootLogicalVolume(innerWallLogic);
264
265 return worldPhys;
266 }
267 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
268