CAVEAT: Basically, I'm just using these pages as a notepad. The idea is to make the doxygen generated commets reflect the stuff here eventually
Overiew
The AcdRecon does a few things.
1) make MIP calibrated quantities from the digis (AcdHit)
2) calculate the distance between hit tiles & ribbons & track extrapolations -> (AcdTkrHitPoca)
3) calculate the intersection point of track extrapolations w/ the ACD (AcdTkrIntersection)
4) caculate the distance to the closest relevent gap in the ACD for track extrapolations (AcdTkrGapPoca & AcdCornerDoca)
5) extract quantities for the merit tuple. (Basically all the other stuff in Event::AcdRecon class)
Algorithm
This is just a list of the order & nesting the various functions are called in.
AcdReconAlg::reconstruct( const Event::AcdDigiCol& digiCol )
Is the main function. It takes the collection of AcdDigis from the event as input.
This function:
1) builds the set of AcdHits (AcdPha2MipTool::makeAcdHits() )
2) calculates all the geometrical quantities for each track and the event vertex ( trackDistances(), vertexDistances(),
AcdTrkIntersectTool::exitsLAT(), AcdPocaTool::tileDistances(), AcdPocaTool::ribbonDistances() )
3) latches best values for storage to Merit Tuple ( doca(), hitTileDist(), tileAcdDist(), hitRibbonDist() )
4) extrapolates track to the ACD ( extrapolateTrack() )
5) puts output on the TDS
AcdPha2MipTool::makeAcdHits(const Event::AcdDigiCol& digiCol, Event::AcdHitCol& hits, AcdRecon::AcdHitMap& hitMap )
Converts all the digis to calibrated AcdHits.
Normally all digis are converted to hits.
Depending on if the hit was read out in the high range or the low range different conversions are applied.
The low range uses a linear conversion:
mips = ( PHA - pedestal ) / mip_peak_PHA
The high range uses a form that is linear for low values, but saturates for high values:
mips = ( ( PHA - pedetsal ) * saturation * slope ) / ( saturation + ( ( PHA - pedestal ) * slope ) )
if ( (PHA - pedestal) * slope << saturation ) this goes to:
mips = ( PHA - pedetsal ) * slope
if ( (PHA - pedestal) * slope >> saturation ) this goes to:
mip = saturation
Both of the conversion functions live in the AcdUtil/AcdCalibFuncs. They are
mipEquivalent_lowRange
mipEquivalent_highRange
AcdReconAlg::trackDistances(...)
Does all the geometrical computations for each track.
Those calculations are:
1) finding the point where the track exits the nominal ACD in both directions (AcdTrkIntersectTool::exitsLAT() )
2) find the docas to the various hit Acd tiles and ribbons ( AcdPocaTool::tileDistances(), AcdPocaTool::ribbonDistances())
AcdPocaTool::tileDistances(...)
This gets the various types of doca & active distance calculations for tiles
AcdRecon::pointPoca() -> doca to center of tile
AcdRecon::tilePlane() -> point that track crosses tile plane & 2D active distance
AcdRecon::tileEdgePoca() or -> doca to closest edge (track inside tile)
AcdRecon::tileEdgeCornerPoca() -> doca to closest edge or corner ( track outside tile )
AcdPocaTool::ribbonDistances(...)
This get the various types of doca & active distance calculations for ribbons
AcdRecon::ribbonPlane() -> point that track crosses ribbon plane
AcdRecon::ribbonPoca() -> doca to ray defined by ribbon
AcdReconAlg::doca(...)
Latches the best (smallest) values of doca to tile center for all tracks
AcdReconAlg::hitTileDist(...)
Latches the best (largest) values of 2D active distance to tiles for all tracks
AcdReconAlg::tileActDist(...)
Latches the best (largest) values of "tileActiveDistance" (2D inside tile, 3D outside tile) for all tracks
AcdReconAlg::hitRibbonDist(...)
Latches the best (largest) value of 2D active distance to ribbons for all tracks
AcdReconAlg::extrapolateTrack(...)
Uses GEANT propagator to take track parameters out tointersection and POCAs. Calls:
AcdTkrIntersecttTool:makeIntersections() -> uses GEANT propagator to caluclate intersection w/ ACD elements
AcdRecon::projectErrorAtPoca() -> propagates error matrix to POCA
AcdTkrIntersectTool::makeIntersections()
Uses GEANT propagator to caluclate intersection w/ ACD elements. If the struck element has not been hit, does the POCA calculations
AcdRecon::ribbonPlane() and AcdRecon::ribbonPoca() or
AcdRecon::tilePlane() and AcdRecon::tileEdgePoca()
AcdRecon::projectToPlane()
Gets the poca to the tile holes ( holePoca() )
Decides where closest gap is, then calls
gapPocaRibbon( ) -> if the track actually hits a ribbon that isn't in an overlap area, uses 3D poca to ribbon center
gapPocaTile( ) -> if the track hits a tile, uses -1 * 3D poca to tile edge
fallbackToNominal() -> if the track doesn't hit any GEANT element, uses 2D "active distance" ( 5. - fabs(x-x0) ) to gap
AcdReconAlg:: calcCornerDoca(...)
Calculates the DOCA to the Rays defined by the side edges of the ACD. Signed to reflect the directionality of the gaps.
Geometrical Functions
These functions are defined in AcdRecon/AcdReconFuncs.h and implemented in src/AcdReconFuncs.cxx
...
Outputs:
arcLength -> distance along the track where the poca occurs => poca = track.m_point + arcLength * track.m_dir
doca -> distance of clostest approach == | point - poca |
poca -> the point of closest approach
crossesPlane(const Track& track, const Point& plane, int face, arcLength
...
, Point& hitPoint)
Gets the point where a track projection crosses a plane. This assumes that the plane is oriented along a cartiesen axis
...
Outputs:
arcLength -> distance along the track where the plane is crossed occurs => hitPoint = track.m_point + arcLength * track.m_dir
localX -> position of the crossing point relative to the plane center
localY hitPoint -> the point where the track projection crosses the plane
crossesPlane(const Track& track, const Transform& trans, arcLength, Point& hitPoint)
Gets the point where a track projection crosses a plane. This does not assume that the plane is oriented along a cartiesen axis
Inputs:
track -> the track projectection data
trans -> transformation for global coordinates to the tile coordinates
Outputs:
arcLength -> distance along the track where the plane is crossed occurs => hitPoint = track.m_point + arcLength * track.m_dir
hitPoint -> the point where the track projection crosses the plane
...
the plane
rayDoca(const Track& track, const Point& p1, const Point& p2, RayDoca& rayDoca, double& edgeLen )
Gets the point where a track comes closest to the ray from point p1 to point p2.
Inputs:
track -> the track projection data
p1, p2 -> intial and final points of the ray, usally two corners of a tile or two end of a ribbon
Outputs:
rayDoca -> object with intesection data
edgeLen -> length along the edge at which the POCA occurs, we check this to make sure the poca occurs between the two ends
rayDoca_withCorner(const Track& track, const
...
Ray&
...
ray,
arcLength
...
, rayLength, dist, Point& x, Vector& v)
Get the point where a track comes closest to a ray. Handles the ends of the ray correctly.
Inputs:
track -> the track projection data
ray -> the ray in question
Outputs:
arcLength -> length along track where POCA occurs
rayLength -> length along ray where POCA occurs
dist -> DOCA
x -> point along track there POCA occurs, (ie, POCA of track to ray)
v -> vector from x to closest point on ray. x-v must be on the ray
tilePlane(const Track& track, const Tile& tile, PocaData &data)
Gets the point where a track projection crosses a tile
Inputs:
track -> the track projectection data
tile -> the geomertical informatio information about the tile
Outputs:
data.arcLength_plane -> distance along the track where the plane is crossed occurs => hitPoint = track.m_point + arcLength * track.m_dir
localX -> position of the crossing point relative to the plane center
localY
data.activeX -> position of the crossing point relative to the edge of the active area ( >0 is in active area)
data.activeY
data.active2D -> the larger of activeX and activeY
hitPoint activeY
data.hitsPlane -> the point where the track projection crosses the plane in global coords
data.inPlane -> the point where the track projection crosses the plane in local coords (+x , +y, -x, -y edges in local frame)
data.volume -> which volume of the tile (0 = main, 1 = bent piece)
tilePlaneActiveDistance(cons Tile& tile, iVol, const Point& globalPoint, Point& localPoint, activeX, activeY )
Gets the active distance of the intersection.
Inputs:
tile -> the geomertical information about the tile
iVol -> which volume of the tile (0 = main, 1 = bent piece)
globalPoint -> intersection point in global coords
Outputs:
localPoint -> intersection point in local coords (+x , +y, -x, -y edges in local frame)
activeX, activeY -> active distances in X and Y
tileEdgePoca(const Track& track, const Tile& tile,arcLength, dist, Point& poca, Vector& vector, int& region)
...
Outputs:
arcLength -> distance along the track where the plane is crossed occurs => hitPoint = track.m_point + arcLength * track.m_dir
dist -> the distance of closest approach between the track and the tile edge (in 3D)
poca -> the point of closest approach along the track to the tile edge
vector -> the vector from the poca to the closest point on the tile edge
region -> a code to show which edge of the tile was considered (y,+x,+y,-x edges, ++, +, --, -+ corners)
ribbonPlane(const Track& track, const Ribbon& ribbon,
...
PocaData& data)
Gets the point where a track projection crosses a plane. This assumes that the plane is oriented along a cartiesen axis
Inputs:
track -> the track projectection data
ribbon -> the geomertical informatio about the tile
Outputs:
arcLength data.arcLengthPlane -> distance along the track where the plane is crossed occurs => hitPoint = track.m_point + arcLength * track.m_dir
dist data.active2D -> the distance of closest approach between the track and the ribbon
hitPoint data.hitsPlane -> the point where the track projection crosses the plane plane
data.volume -> which segment of the ribbon
ribbonPoca(const Track& track, const Ribbon& ribbon, arcLength, ribbonLength, dist, Point& poca, Vector& vector, int& region)
Gets the point where a track projection crosses a plane. This assumes that the plane is oriented along a cartiesen axis
...
Outputs:
arcLength -> distance along the track where the plane is crossed occurs => hitPoint = track.m_point + arcLength * track.m_dir
ribbonLength -> distance along the ribbon where the POCA occurs, 0 is center of ribbon
dist -> the distance of closest approach between the track and the ribbon
poca -> the point of closest approach along the track to the ribbon
vector -> the vector from the poca to the closest point on the ribbon
region -> a code to show which edge of the ribbon was considered (+,- in local coords)
Track Projection Functions
...
// stuff about where the POCA occurs relative to the tile or ribbon
int m_region; // One of the enums in "??"
TrackData
HepPoint3D m_point; // the start (or end) point of the track
HepVector3D m_dir; // the direction of the track
double m_energy; // the energy of the track at the start point
int m_index; // the index number of this track
bool m_upward; // which side of track
ExitData
int m_face; // 0:top 1:-X 2:-Y 3:+X 4:+Y 5:bottom
double m_arcLength; // Length along the track to the m_x
Point m_x; // Intersection Point