MarlinTPC  1.2.0
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marlintpc::localHelix Class Reference

Local Helix. More...

#include <SimpleHelixTrackModel.h>

Public Member Functions

 localHelix (const double *, const double *, const double)
 Constructor. More...
 
void dump () const
 Dump helix.
 
TMatrixD propagateTo (const double *, const double)
 Propagate stepwise (close) to point. More...
 
simpleHelix getSimpleHelix () const
 Get simple helix. More...
 

Detailed Description

Local Helix.

Utilities for local helix track model build from perigee parameters and magnetic field at the PCA (point of closest approach) to the reference point, assuming constant magnetic field in arbitrary direction.

In a local system a simple helix is used. The offset of the local system is the PCA of the track (to the reference point) and the directions are (p,n,h), h is the direction of the magnetic field, n = h x t / |h x t| with track direction t and p = n x h. The bending plane is defined by p and n and p is the local track direction at the PCA in this plane.

Implemented is a stepwise propagation in a changing (only locally constant) magnetic field.

Propagation and transformation jacobians according to Strandlie & Wittek (NIM A 566(2006) 687-698)

Author
C. Kleinwort, DESY (131112)

Constructor & Destructor Documentation

marlintpc::localHelix::localHelix ( const double *  parameters,
const double *  refPoint,
const double  bScale 
)

Constructor.

Parameters
[in]parameters(global) helix parameters (at)
[in]refPointreference point
[in]bScalescale factor for magnetic field (0/1)

Member Function Documentation

simpleHelix marlintpc::localHelix::getSimpleHelix ( ) const

Get simple helix.

Get simple helix in global system at current reference point.

Returns
simple helix
TMatrixD marlintpc::localHelix::propagateTo ( const double *  point,
const double  mstep 
)

Propagate stepwise (close) to point.

Stepwise propagation in a changing (only locally constant) magnetic field. Reference point is changed to (PCA of) target.

Parameters
[in]pointtarget (propagate to PCA)
[in]mstepmaximal step size with constant magnetic field
Returns
analytical propagation jacobian

References marlintpc::localHelixAnalyticalJacobian().


The documentation for this class was generated from the following files: