StraightLineTOFcorrectionTool.cxx

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#include "StraightLineTOFcorrectionTool.h"
 
#include "GaudiKernel/PhysicalConstants.h"
#include "HGTD_PrepRawData/HGTD_Cluster.h"
#include "HGTD_ReadoutGeometry/HGTD_DetectorElement.h"
#include "TrkTrack/Track.h"
 
HGTD::StraightLineTOFcorrectionTool::StraightLineTOFcorrectionTool(
    const std::string& t, const std::string& n, const IInterface* p)
    : base_class(t, n, p) {}
 
StatusCode HGTD::StraightLineTOFcorrectionTool::initialize() {
 
  ATH_CHECK(AlgTool::initialize());
 
  ATH_CHECK(detStore()->retrieve(m_hgtd_det_mgr, "HGTD"));
 
  return StatusCode::SUCCESS;
}
 
std::pair<float, float>
HGTD::StraightLineTOFcorrectionTool::correctTimeAndResolution(
    const Trk::Track& track, const HGTD_Cluster& cluster,
    const float time_of_arrival, const float time_of_arrival_err) const {
 
  ATH_MSG_DEBUG("Correcting input time: " << time_of_arrival);
 
  // FIXME: This should work with 'globalPosition' of the cluster alone, but no
  // det element set during P->T conversion!
  const InDetDD::HGTD_DetectorElement* det_el =
      m_hgtd_det_mgr->getDetectorElement(cluster.identify());
 
  // get the distance between the track origin and the hit position
  const Trk::Perigee* perigee = track.perigeeParameters();
  Amg::Vector3D glob_hit_pos = det_el->globalPosition(cluster.localPosition());
 
  float dx = glob_hit_pos.x() - perigee->position().x();
  float dy = glob_hit_pos.y() - perigee->position().y();
  float dz = glob_hit_pos.z() - perigee->position().z();
 
  // compute TOF between origin and hit position
  // FIXME define 1/c somewhere as constexpr?
  // FIXME since this is an approximation anyway, can we use a fast sqrt?
  float tof = std::sqrt(dx * dx + dy * dy + dz * dz) / Gaudi::Units::c_light;
  float corrected_toa = time_of_arrival - tof;
 
  ATH_MSG_DEBUG("Corrected time: " << corrected_toa);
 
  // TODO
  // the intrinsic resolution on the time of arrival needs to be combined
  // with the impact parameter resolution and the spatial resolution of the
  // cluster. no large impact is expected though
 
  return {corrected_toa, time_of_arrival_err};
}