Advanced European Infrastructures for Detectors at Accelerators
Alignment Support for the
DD4hep Geometry Description
CERN, 1211 Geneva 23, Switzerland
Experimental setups in High Energy Physics are highly complex assemblies consisting of
various detector devices typically called subdetectors. Contrary to the ideal world, where
all these components are of perfect shape and at exact positions, existing devices have
imperfections both in their shape and their relative and absolute positions. These are
described by the alignment parameters.
To still measure the detector response from particle collisions with the highest possible precision, these imperfections are taken into account when converting measured signals to space-points in the measurement devices. This procedure is called detector alignment. does not want to solve the exact problem of the detector alignment itself, but rather support ﬁrstly algorithms determining the alignment parameters and secondly support the application which apply the measured alignment parameters and apply them to the ideal geometry for further event data processing.
We will present the tools to support the detector alignment procedures using the detector description toolkit. The DDAlign toolkit implements a modular and ﬂexible approach to introduce and access the alignment parameters.
The design is strongly driven by easy of use; developers of detector descriptions and applications using them should provide minimal information and minimal speciﬁc code to achieve the desired result.
|1.0||01/04/2014||Markus Frank CERN/LHCb|
|1.1||30/04/2014||Markus Frank CERN/LHCb|
|1.2||28/02/2017||Markus Frank CERN/LHCb|
1.1 Generic Detector Description Model
1.2 Detector Element Tree and the Geometry Hierarchy
2 Global Alignment
2.1 Global Alignment of Detector Components
2.2 Iterative Application of Global Alignments
2.3 Procedures to Determine Global Alignment Parameters
2.4 Simulation of Non-Ideal Detector Geometries
2.5 The Global Alignment Interface
3 Up to here the manual should be pretty much correct.
Everything below is at least questionable.
4 Local Alignment
5 The Local Alignment Interface
5.1 Access to Alignment Parameters from the Detector Element
5.2 Manipulation of Alignment Parameters