Detector Description in GAUDI Architecture Detector Logical Structure

Detector Description in GAUDI • Architecture • Detector Logical Structure • Extending Detector Element • Summary Workshop on Geometry Toolkit for the Linear Collider 24 th February 2010 P. Mato / CERN

Detector Description Architecture u u Sub-Architecture of Gaudi – Same principles – Transient/Persistent representations Focus on the “Physics Algorithm” – Access to Detector Transient Store Coherent access to “all” detector data – Geometry, Calibration, Slow Control, etc. Gaudi Architecture Application Manager Message Service Job. Options Service u Converter Event Selector Event Data Service Other Services Data Files Transient Event Store Algorithm Particle Prop. Service Persistency Service Detec. Data Service Transient Detector Store Persistency Service Data Files Histogram Service Transient Histogram Store Persistency Service Data Files CHEP 03 Paper: http: //www. slac. stanford. edu/econf/C 0303241/proc/papers/THJT 007. PDF 01/06/2004 Gaudi Detector Element 2

Algorithm Accessing Detector Data • Manages store • Synchronization updates begin. Event request Detector. Data Service request: get, update Persistency Service IDet. Element IGeometry. Info Geometry Info Algorithm Det. Element ICalibration IRead. Out reference Geometry Conversion Service Conditions DB Conversion Service Other DBs Read. Out Muon. Station Transient Detector Store 01/06/2004 Conversion Service Gaudi Detector Element 3

Detector Description u Logical Structure – Breakdown of detectors – Identification u Geometry Structure – Hierarchy of geometrical volumes – Logical. Volumes (unplaced) – Physical. Volumes (placed) u Other detector data – Calibration, Alignment, Readout maps, Slow control, etc. 01/06/2004 Gaudi Detector Element 4

Two Hierarchies Logical structure Geometry structure Det. Element LVolume LHCb Experiment Det. Element Tracking Calo Det. Element HCAL ECAL PVolume LVolume ECAL HCAL RICH PVolume Det. Element Module 1 Module 2 PVolume LVolume HCALModule Detector Description 01/06/2004 Geometry Gaudi Detector Element 5

Logical Structure u u The basic object is a Detector Element – Identification – Navigation (tree-like) Detector. Element as information center – Be able to answer any detector related question » E. g. global position of strip#, temperature of detector, absolute channel gain, etc. Det. Element * My. Detector – Placeholder for specific code » The specific answers can be coded by “Physicists” u Detector. Element objects are shared by all Algorithms 01/06/2004 Gaudi Detector Element 6

Simplified Diagram (simplified) Data. Object Hierarchy IDetector. Element IGeometry. Info Geometry Info Detector. Element IRead. Out ICalibration Muon. Station Calibration Specific detector description questions from algorithms Detector Description 01/06/2004 Read. Out Association resolved on demand * ILVolume * LVolume Material ISolid IPVolume Solid. Box Geometry Gaudi Detector Element Mixture Element * Isotope * Material 7

Detector Element Class u Three basic functionalities: – IDetector. Element: Access to other Detector information – IValidity: Time validity interval management – Param. List: User parameters (key-value pairs) 01/06/2004 Gaudi Detector Element 8

Transient Store Organization u Standard Gaudi Transient Store – “Catalogs” of Logical Volumes and Materials – “Structure” as a tree – All elements identified with names of the form: /xxx/yyy/zzzz 01/06/2004 Gaudi Detector Element 9

Persistency Based on XML Files u u XML is used as persistent representation of the Structure, Geometry and Materials Why XML? • Instead of inventing our own format use a standard one (extendible) • Many available Parsers and Tools • Strategic technology 01/06/2004 Gaudi Detector Element <DDDB> <catalog name=“…"> <detelem name=“…"> <geometryinfo lvname=“…” npath=“…” support=“…”/> <user. Parameter comment=“…” name=“…” type="string"> … </user. Parameter> <specific> … </specific> </detelem> </catalog> </DDDB> 10

Specializing Detector Elements 1. Adding user. Parameter(vector)s to default Detector. Elements 2. Extending and specializing the Detector. Element class in C++, using user. Parameters in XML 3. Extending XML DTD and writing a dedicated converter 01/06/2004 Gaudi Detector Element 11

Summary u Detector Element is the central point for offering Detector information to Algorithms – Can be customized to answer specific questions » Global sub-detector questions should be asked to the Detector Element that represents a sub-detector » Module specific questions should be asked to Detector element that represents a module u u u Access similar to any GAUDI Data Transient Store Persistency representation based on XML Three possibilities for specializing Detector Elements – Adding user. Parameter to default Detector. Elements – Extending and specializing the Detector. Element class in C++, using user. Parameters in XML – Extending XML DTD and writing a dedicated converter 01/06/2004 Gaudi Detector Element 12