Merge pull request #83 from DUNE/82-change-ecal-al-plate-shape-to-trapezoid

82 change ecal al plate shape to trapezoid

Author: mt82

CHANGELOG.md

@@ -14,6 +14,7 @@ These geometry releases were tagged as `Descriptive_tag_v_X.Y.Z`.
 - Removed the stale SAND tracker geometry options from the default `sandopt` list. Only the supported full STT, full Drift-Chamber and Initial STT geometries are now built.
 - Updated TMS cassette ordering to the final design (50 X, 32 Y; 8×(X+Y) + 22×(X+X+Y)) 
 - Updated the active and passive layer thicknesses of ECAL modules to match the detector specifications, 620 um and 480 um respectively.
+- Updated the shape of the SAND barrel module Al plate to a trapezoid matching the overall module shape.
 
 ## [v2025.08.11]
 

duneggd/Component/SandECalBarrelMod.py

@@ -40,11 +40,19 @@ def construct(self, geom):
         self.add_volume(ECAL_lv)
 
             ######## Aluminum back plate##################
-
-        ECAL_Alplate_shape = geom.shapes.Box('ECAL_Alplate_shape',
-                                           dx = self.trapezoidDim[1],
-                                           dy = self.trapezoidDim[2],
-                                           dz = AlPlateThick/2.)
+        
+        #tan = math.tan(math.pi/self.Segmentation)
+        tan = 0.5*(self.trapezoidDim[1] - self.trapezoidDim[0])/self.trapezoidDim[3]
+        
+        bhalfAlPlate=self.trapezoidDim[1]
+        BhalfAlPlate=bhalfAlPlate+AlPlateThick*tan
+        
+        ECAL_Alplate_shape = geom.shapes.Trapezoid('ECAL_Alplate_shape',
+                            dx1=bhalfAlPlate,
+                            dx2=BhalfAlPlate,
+                            dy1=self.trapezoidDim[2],
+                            dy2=self.trapezoidDim[2],
+                            dz=AlPlateThick/2.)
 
         ECAL_Alplate_lv = geom.structure.Volume('ECAL_Alplate_lv', material = 'Aluminum', 
                                               shape = ECAL_Alplate_shape)
@@ -58,8 +66,6 @@ def construct(self, geom):
         ECAL_lv.placements.append(ECAL_Alplate_place.name)
 
         for i in range(self.nSlabs): #nSlabs
-            #tan = math.tan(math.pi/self.Segmentation)
-            tan = 0.5*(self.trapezoidDim[1] - self.trapezoidDim[0])/self.trapezoidDim[3]
             xposSlab=Q('0cm')
             yposSlab=Q('0cm')
             zposSlabActive = (-self.trapezoidDim[3]-AlPlateThick/2. +