$Id$ =========================================================== General Information about MUON Geometry =========================================================== Our geometry is described in the geometry builder classes. Main geometrical constants are set in the class AliMUONConstants. The code can then generate the geometry data files transform.dat and svmap.dat (see description below) via the macro MUONGenerateGeometryData.C (more info below). The geometry data files have to be recreated each time the code of the geometry is modified. The info (well updated) in this files (svmap) is need during the simulation. We can also decide to use the transform.dat file as input of our geometry. This allows for changing the position of our detection elements and/or half-planes (half-chambers in code jargon) without modifying and recompiling the code. First step in the official aliroot simulation process is to create the geometry.root file from the builders to build the MUON geometry within the geometrical modeler framework of root. Then aliroot takes the geometry.root file as a unique geometrical info of our apparatus during the generation and the reconstruction and analysis (if needed) Misalignments are in the official AliRoot code applied to the geometry.root file. Geometry data files description transform.dat ------------- List of transformations for chambers geometry modules and detection elements; in format: KEY ID [nofDE] pos: posX posY posZ rot: theX phiX theY phiY theZ phiZ where KEY = CH or DE ID = chamberId or detElemId pos: posX posY posZ = position in cm rot: theX phiX theY phiY theZ phiZ = rotation angles as in Geant3 in deg svmap.dat ------------- Map of sensitive volumes to detction element Ids; in format: KEY volpath detElemId where KEY = SV volpath = volume path in format /volname1_copyNo1/volname2_copyNo2/... detElemId = detection element Id ============================================================ How to check the Geometry with the new Geometrical modeler ftp://root.cern.ch/root/doc/chapter16.pdf http://agenda.cern.ch/fullAgenda.php?ida=a05212 ============================================================ gAlice->Init("$ALICE_ROOT/MUON/Config.C"); gGeoManager->GetMasterVolume()->Draw(); ============================================================ How to check the overlap with the new Geometrical modeler ftp://root.cern.ch/root/doc/chapter16.pdf http://agenda.cern.ch/fullAgenda.php?ida=a05212 ============================================================ gAlice->Init("$ALICE_ROOT/MUON/Config.C"); gGeoManager->CheckOverlaps(); gGeoManager->PrintOverlaps(); =========================================================== Macro MUONGenerateGeometryData.C =========================================================== Macro for generating the geometry data files Geometry data files: - MUON/data/transform.dat file contains the transformations data (translation and rotation) for all alignable objects (modules & detection elements) - MUON/data/svmap.dat file contains all the information to link each geant volume (it can be extended to other virtual MC) with a detection element. The point here is that a given detection element, i.e. a slat chamber can consist of more geant volumes. the correspondence is then defined in an input file. Each time there is a change in the definition of MC geometry, these input files must be re-generated via the macro MUONGenerateGeometryData.C To be run from aliroot: .x MUONGenerateGeometryData.C The generated files do not replace the existing ones but have different names (with extension ".out"). Replacement with new files has to be done manually. =========================================================== Macros to generate Mis-alignment data =========================================================== Macro for generating the geometry mis-alignment data: MakeMUONFullMisAlignment.C MakeMUONResMisAlignment.C MakeMUONZeroMisAlignment.C To be run from aliroot: .x MakeMUONFullMisAlignment.C etc. If the environment variable TOCDB is not set to "kTRUE", the misalignment data are generated in a local file: (MUONFullMisalignment.root, etc.) If the data are stored in CDB, the storage can be specified in the environment variable STORAGE. The misalignment data are then generated in the CDB folder (defaults are ResMisAlignCDB and FullMisAlignCDB in the working directory). Inside the local CDB the path for the alignment data is (and must be) "MUON/Align/Data/". Residual misalignment: Default is our current estimate of misalignment after all our alignment procedure has been applied. Full misalignment: Default is our current estimate of initial misalignment. ========================================================== How to check the alignment software ========================================================== The script AlirootRun_MUONtestAlign.sh allows you to check the software for the alignment with physics tracks. The script will: - Generate a misaligned geometry in a local CDB (default FullMisAlignCDB) - Simulate 1000 events using previously misaligned geometry - Reconstruct the events using perfect geometry - Run the alignment code over the above events using MUONAlignment.C To run you need to type: $ALICE_ROOT/MUON/AlirootRun_MUONtestAlign.sh The results of the test are saved in test_align/ directory. The file measShifts.root contains useful graphs for studying the alignment performances. A local CDB containing the realigned geometry is also created (default is ReAlignCDB). The file $ALICE_ROOT/MUON/data/transform2ReAlign.dat contains the transformations describing the realigned geometry to be compared with the used misaligned geometry $ALICE_ROOT/MUON/data/transform2.dat. IMPORTANT NOTE: For a useful test of the alignment performances, the order of 100 000 tracks is needed, it is then advisable to generate and reconstruct enough events separately and run MUONAlignment.C providing a file list afterwards.