GeneralBrokenLines V03-01-02
gblpy3
Classes | Functions
gblsit3 Namespace Reference

Classes

class  gblHelixPrediction
 Prediction (from helix at measurement) More...
 
class  gblSiliconDet
 Silicon detector. More...
 
class  gblSiliconLayer
 Silicon layer. More...
 
class  gblSimpleHelix
 Simple helix. More...
 

Functions

def exampleSit ()
 Simulate and reconstruct helical tracks in silicon pixel and (1D or 2D) strip detectors. More...
 
def gblSimpleJacobian (ds, cosl, bfac)
 Simple jacobian. More...
 
def gblMultipleScatteringError (qbyp, xbyx0)
 Multiple scattering error. More...
 

Detailed Description

Created on 28 Sep 2018

@author: kleinwrt

Function Documentation

◆ exampleSit()

def gblsit3.exampleSit ( )

Simulate and reconstruct helical tracks in silicon pixel and (1D or 2D) strip detectors.

Create points on initial trajectory, create trajectory from points, fit and write trajectory to MP-II binary file (for rigid body alignment).

Setup:

  • Beam (mainly) in X direction
  • Constant magnetic field in Z direction
  • Silicon sensors measuring in YZ plane, orthogonal (pixel) or non-orthogonal (stereo strips, double sided or composite) measurement systems
  • Multiple scattering in sensors (air inbetween ignored)
  • Curvilinear system (T,U,V) as local coordinate system and (q/p, slopes, offsets) as local track parameters

Alignment with MP-II. The alignables are the objects to be aligned. This can be single detector elements (with a 1D or 2D measurement) or sets of those with similar or different orientations.

Local systems. Up to three (different) local coordinate systems can be defined at each point:

  • Track model linearization (propagation, fitting), e.g. curvilinear system
  • Measurement, defined by two (optionally non-orthogonal) measurement directions, normal to detector plane and detector position (offset)
  • Alignment, defined by two orthogonal directions in detector plane, normal to that and detector position (offset). If different from measurement system for alignables with a single 1D measurements the unmeasured component has to be fixed by a linear equality constraint for MP-II.
Remarks
To exercise (mis)alignment different sets of layers (with different geometry) for simulation and reconstruction can be used.

Example steering file for Millepede-II (B=0):

Cfiles
milleBinary.dat
method inversion 3 0.1
chiscut 30. 6.
printcounts
! fix first pixel and last stereo layer as reference
parameter
1 0. -1.
2 0. -1.
3 0. -1.
4 0. -1.
5 0. -1.
6 0. -1.
61 0. -1.
62 0. -1.
63 0. -1.
64 0. -1.
65 0. -1.
66 0. -1.
! from "det.getMP2Constraints()":
! Alignment with MillePede-II requires for 1D measuremnts:
Constraint 0. ! fix unmeasured direction in S1D8
72 1.0
! End of lines to be added to MillePede-II steering file

Definition at line 93 of file gblsit3.py.

References gblMultipleScatteringError(), and gblSimpleJacobian().

Referenced by gblsit3.gblHelixPrediction.getCurvilinearDirs().

◆ gblMultipleScatteringError()

def gblsit3.gblMultipleScatteringError (   qbyp,
  xbyx0 
)

Multiple scattering error.

Simple model (Rossi, Greisen)

Parameters
[in]qbypq/p [1/GeV]; float
[in]xbyx0thickness / radiation length; float

Definition at line 251 of file gblsit3.py.

Referenced by exampleSit(), and gblsit3.gblSiliconDet.generateHits().

◆ gblSimpleJacobian()

def gblsit3.gblSimpleJacobian (   ds,
  cosl,
  bfac 
)

Simple jacobian.

Simple jacobian for (q/p, slopes, offsets) in curvilinear system, constant magnetic field in Z direction, quadratic in arc length difference.

Parameters
dsarc length difference; float
coslcos(lambda); float
bfacBz*c; float
Returns
jacobian to move by 'ds' on trajectory matrix(float)

Definition at line 235 of file gblsit3.py.

Referenced by exampleSit().