gblsit 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 gblsit.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 gblsit.py.

References gblMultipleScatteringError(), and gblSimpleJacobian().

Referenced by gblsit.gblHelixPrediction.getCurvilinearDirs().

gblMultipleScatteringError()

def gblsit.gblMultipleScatteringError	(		qbyp,
			xbyx0
	)

Multiple scattering error.

Simple model (Rossi, Greisen)

Parameters

[in]	qbyp	q/p [1/GeV]; float
[in]	xbyx0	thickness / radiation length; float

Definition at line 251 of file gblsit.py.

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

gblSimpleJacobian()

def gblsit.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

ds	arc length difference; float
cosl	cos(lambda); float
bfac	Bz*c; float

Returns

jacobian to move by 'ds' on trajectory matrix(float)

Definition at line 235 of file gblsit.py.

Referenced by exampleSit().