epic/src/BackwardsBeamPipe_geo.cpp

0001 // SPDX-License-Identifier: LGPL-3.0-or-later
0002 // Copyright (C) 2022 Wouter Deconinck, Simon Gardner, Whitney Armstrong
0003
0004 //==========================================================================
0005 //   Beampipe described by end points with different radii at either end
0006 //==========================================================================
0007 //
0008 //      <detector id="Pipe_in" name ="DetName" type="BackwardsBeamPipe" >
0009 //        <Pipe wall_thickness="pipe_thickness" outerD1="start_radius" outerD2="end_radius"
0010 //        end1z="start_z" end2z="end_z" end1x="start_x" end2x="end_x"/>
0011 //      </detector>
0012 //
0013 //==========================================================================
0014
0015 #include "DD4hep/DetFactoryHelper.h"
0016 #include "DD4hep/Printout.h"
0017 #include "TMath.h"
0018 #include <XML/Helper.h>
0019
0020 using namespace std;
0021 using namespace dd4hep;
0022
0023 static Ref_t create_detector(Detector& det, xml_h e, SensitiveDetector /* sens */) {
0024
0025   using namespace ROOT::Math;
0026   xml_det_t x_det = e;
0027   string det_name = x_det.nameStr();
0028   DetElement sdet(det_name, x_det.id());
0029   Assembly assembly(det_name + "_assembly");
0030   Material m_Al     = det.material("Aluminum");
0031   Material m_Vacuum = det.material("Vacuum");
0032   string vis_name   = dd4hep::getAttrOrDefault<std::string>(x_det, _Unicode(vis), "BeamPipeVis");
0033
0034   xml::Component Pipe_c = x_det.child(_Unicode(Pipe));
0035
0036   // Get pipe dimensions from xml
0037   double thickness = Pipe_c.attr<double>(_Unicode(wall_thickness));
0038   double innerD1   = Pipe_c.hasAttr(_Unicode(innerD1))
0039                          ? Pipe_c.attr<double>(_Unicode(innerD1))
0040                          : Pipe_c.attr<double>(_Unicode(outerD1)) - 2 * thickness;
0041   double innerD2   = Pipe_c.hasAttr(_Unicode(innerD2))
0042                          ? Pipe_c.attr<double>(_Unicode(innerD2))
0043                          : Pipe_c.attr<double>(_Unicode(outerD2)) - 2 * thickness;
0044
0045   double end1z = Pipe_c.attr<double>(_Unicode(end1z));
0046   double end2z = Pipe_c.attr<double>(_Unicode(end2z));
0047   double end1x = dd4hep::getAttrOrDefault<double>(Pipe_c, _Unicode(end1x), 0.0);
0048   double end2x = dd4hep::getAttrOrDefault<double>(Pipe_c, _Unicode(end2x), 0.0);
0049
0050   double length = sqrt((end1z - end2z) * (end1z - end2z) + (end1x - end2x) * (end1x - end2x));
0051   double yrot   = atan((end1x - end2x) / (end1z - end2z));
0052
0053   // -----------------------------
0054   // Make beampipe shape
0055   ConeSegment tube_vacuum(length / 2.0, 0.0, innerD1 / 2.0, 0.0, innerD2 / 2.0);
0056   ConeSegment tube_tube(length / 2.0, innerD1 / 2.0, innerD1 / 2.0 + thickness, innerD2 / 2.0,
0057                         innerD2 / 2.0 + thickness);
0058
0059   Volume v_vacuum("v_vacuum", tube_vacuum, m_Vacuum);
0060   Volume v_tube("v_tube", tube_tube, m_Al);
0061
0062   sdet.setAttributes(det, v_tube, x_det.regionStr(), x_det.limitsStr(), vis_name);
0063
0064   assembly.placeVolume(v_vacuum, Position(0, 0, -length / 2.0));
0065   assembly.placeVolume(v_tube, Position(0, 0, -length / 2.0));
0066
0067   // -----------------------------
0068   // final placement
0069   auto pv_assembly = det.pickMotherVolume(sdet).placeVolume(
0070       assembly, Transform3D(RotationY(yrot), Position(end1x, 0.0, end1z)));
0071   pv_assembly.addPhysVolID("system", sdet.id()).addPhysVolID("barrel", 1);
0072   sdet.setPlacement(pv_assembly);
0073   assembly->GetShape()->ComputeBBox();
0074   return sdet;
0075 }
0076
0077 DECLARE_DETELEMENT(BackwardsBeamPipe, create_detector)