TRD shift tracklet position by one pad

AliceO2Group · Feb 29, 2024 · 015bb0c · 015bb0c
1 parent bab05ed
commit 015bb0c
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Showing 3 changed files with 5 additions and 25 deletions.
diff --git a/DataFormats/Detectors/TRD/include/DataFormatsTRD/Tracklet64.h b/DataFormats/Detectors/TRD/include/DataFormatsTRD/Tracklet64.h
@@ -138,20 +138,14 @@ class Tracklet64
   GPUd() float getPadWidth() const { return 0.635f + 0.03f * (getDetector() % constants::NLAYER); }
 
   // pad column number inside pad row as float
-  GPUd() float getPadColFloat() const { return getPositionFloat() + getMCMCol() * constants::NCOLMCM + constants::NADCMCM / 2.f; }
+  // FIXME: understand why the offset seems to be 8 pads and not nChannels / 2 = 10.5
+  GPUd() float getPadColFloat() const { return getPositionFloat() + getMCMCol() * constants::NCOLMCM + 8; }
 
   // pad column number inside pad row as int can be off by +-1 pad (same function name as for TRD digit)
-  // FIXME: understand why the offset seems to be 8 pads and not nChannels / 2 = 10.5
-  GPUd() int getPadCol() const { return GPUCA_NAMESPACE::gpu::CAMath::Nint(getPadColFloat() - 2); }
+  GPUd() int getPadCol() const { return GPUCA_NAMESPACE::gpu::CAMath::Nint(getPadColFloat()); }
 
   // translate local position into global y (in cm) not taking into account calibrations (ExB, vDrift, t0)
-  GPUd() float getUncalibratedY() const
-  {
-    // one pad column has 144 pads, the offset of -63 is the center of the first MCM in that column
-    // which is connected to the pads -63 - 9 = -72 to -63 + 9 = -54
-    int offsetInNumberOfPads = -63 + constants::NCOLMCM * getMCMCol();
-    return (offsetInNumberOfPads + getPositionFloat()) * getPadWidth();
-  }
+  GPUd() float getUncalibratedY() const { return (getPadColFloat() - (constants::NCOLUMN / 2.f)) * getPadWidth(); }
 
   // translate local slope into dy/dx with dx=3m (drift length) and default drift time in time bins (19.4 timebins / 3cm)
   GPUd() float getUncalibratedDy(float nTbDrift = 19.4f) const { return getSlopeFloat() * getPadWidth() * nTbDrift; }

diff --git a/Detectors/TRD/base/include/TRDBase/TrackletTransformer.h b/Detectors/TRD/base/include/TRDBase/TrackletTransformer.h
@@ -33,8 +33,6 @@ class TrackletTransformer
   void setCalVdriftExB(const CalVdriftExB* cal) { mCalVdriftExB = cal; };
   void setApplyXOR() { mApplyXOR = true; }
 
-  float calculateY(int hcid, int column, int position, const PadPlane* padPlane) const;
-
   float calculateZ(int padrow, const PadPlane* padPlane) const;
 
   float calculateDy(int hcid, int slope, const PadPlane* padPlane) const;

diff --git a/Detectors/TRD/base/src/TrackletTransformer.cxx b/Detectors/TRD/base/src/TrackletTransformer.cxx
@@ -27,18 +27,6 @@ void TrackletTransformer::init()
   mXAnode = mGeo->cdrHght() + mGeo->camHght() / 2;
 }
 
-float TrackletTransformer::calculateY(int hcid, int column, int position, const PadPlane* padPlane) const
-{
-  double padWidth = padPlane->getWidthIPad();
-  int side = hcid % 2;
-  position += 1 << (NBITSTRKLPOS - 1); // shift such that position = 1 << (NBITSTRKLPOS - 1) corresponds to the MCM center
-  // slightly modified TDP eq 16.1 (appended -1 to the end to account for MCM shared pads)
-  double pad = float(position - (1 << (NBITSTRKLPOS - 1))) * GRANULARITYTRKLPOS + NCOLMCM * (4 * side + column) + 10. - 1.;
-  float y = padWidth * (pad - 72);
-
-  return y;
-}
-
 float TrackletTransformer::calculateZ(int padrow, const PadPlane* padPlane) const
 {
   double rowPos = padPlane->getRowPos(padrow);
@@ -114,7 +102,7 @@ CalibratedTracklet TrackletTransformer::transformTracklet(Tracklet64 tracklet, b
 
   // 5mm below cathode plane to reduce error propogation from tracklet fit and driftV
   float x = mGeo->cdrHght() - 0.5;
-  float y = calculateY(hcid, column, position, padPlane);
+  float y = tracklet.getUncalibratedY();
   float z = calculateZ(padrow, padPlane);
 
   float dy = calculateDy(detector, slope, padPlane);