Core Framework
a framework has to be set up that
- builds under Java 1.4 (Maven, ant,....)
- builds with gcj (make)
- reads xml files
-
- initially use compact format
- gradually extend/modify as needed
- drivers need to read xml and implement gear
- drivers should create geometry elements
- for detailed view (low level)
- for tracking view (mid level)
- initially export to GDML/LCDD should be suported
optionally some wrapping C++ code should be provided that allows to use LCGO in a C++ programm w/o having to rely on references to Java libraries, e.g. for the properties interface
- need to understand garbage collection for java and C++ objects allocated on the stack and on the heap and passing object between java and c++
- java objects are objects inheriting from java::lang::Object
- C++ are all other objects
- Possibly interesting article http://gcc.gnu.org/ml/java/2004-03/msg00159.html
Material Database
a material data base is needed that
- consists of the known materials
- has all the material properties needed for dE/dx
- A, Z (mean values) , X0, Interaction length,....
-
- check geant4/geant3 which these are
- is extensible by the user in input xml files
- provides material objects assigned to volumes (tracking) that give
- material properties
- dEdx( PDG, p , flightlength )
- optionally: dEdx( PDG, p , tracjectory ) ?
- material properties/names should be consistent
-
- with geant4
- NIST database (the same ?)
Field map
LCGO needs to provide a mechanism for field maps
- should allow simple field definitions in xml file, e.g.
- <BField x="0.0" y="0.0" z="4.0" unit="Tesla"/>
- or better: <BField x="0.0" y="0.0" z="4.0*Tesla" /> (see System of Units)
- should allow arbitrary field map from file, e.g.
- <BFIeld file="http://some.server.anywhere/ILCDetailedBField.map"/>
- need well defined file format and corresponding implementation class
- need well defined simple interface, e.g.
-
- interface Field { public Vector3D at( Vector3D x) ; }
- interface Field { public Vector3D at( Vector3D x) ; }
Readout Properties
LCGO drivers need to provide an implementation of an interface to query cellIDs, positions and neighbors:
- cellId <-> position
- cellid range (noise simulation)
- cell sizes
- neighbors
Geometry Elements
we need a full set of geometry classes that allow
- to construct the detailed low level view of the detector
- are used to create other representations
- geant4
-
- GDML/LCDD
- HepRep
- all classes currently available in geant4 should be represented - ideally with the same interface
- shapes (Box, Tube, Polycone,....)
- logical volume (with material...)
- physical volumes with placement,i.e.
- rotation
- translation
- parent volume
- initially the volume heirarchy just needs to be static in order to allow creation of other representations
- issues/requiremnents
-
- names
- copy numbers
- sensitive detectors
- visualization attributes
- user defined attributes
Tracking Geometry
for the tracking (pattern recognition and fitting) a somewhat simplified representation of the detector volumes is needed with
- averaged material (see material, dEdx)
- simple shapes only:
- boxes - planes ?
- tubes - cylinders ?
this tracking geometry should allow to compute:
- intersection with given trajectory
-
- line
- helix
- ...
GEAR API
the mid and high level view of the geometry should be an extension of the current GEAR API
- should allow to represent current detector concepts' subdetectors
- provide high level view as needed for
-
- reconstruction
- digitization
- should provide the geometrical functionality as needed for tracking
- should be the interface all client programs use to get information from LCGO (except low level view)
need to review what is currently in GEAR and define what is missing !
System of Units
it is probably desirable to have a well defined system of units a la Geant4, so that every quantity comes in the properly defined unit. So that one can write code, such as:
cout << " length of TPC [cm]: " << lcgo->getTPCParameters()->getLength() / cm << endl ;
Vectors and Matrices
need to define classes for vectors and matrices (symmetric) that are used throughout LCGO (and LCIO !?)
- 3d vectors
- rotations 3d
- translations (3d vectors)
- 4 vectors (in LCGO ?)
- matrix
- symmatrix
- ...