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Status of Alignment Tools

Status of Alignment Tools. Concept Status Plans. Overview. CMS event/ alignment syst. Geant simulation. Raw DATA Hits in numbered modules. Alignment DB D Tracker D HalfBarrel D BarrelLayer D Rod D DetUnit. Geometry DB. Raw DATA Hits in located modules.

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Status of Alignment Tools

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  1. Status of Alignment Tools Concept Status Plans Helge Voss

  2. Overview CMS event/ alignment syst. Geant simulation Raw DATA Hits in numbered modules Alignment DB DTracker DHalfBarrel DBarrelLayer DRod DDetUnit Geometry DB Raw DATA Hits in located modules Real life: start with AlignmentDB =0 or acc.survey update geometryDB(when?) Testing: AlignmentDB = 0 study effects of mis- alignment/ try to realign Alignment with Tracks/ Lasersytem Track/Laser reconstruction Helge Voss

  3. real tracks are on a “perfect” helix • reconstructed hits do NOT lie on a perfect helix • mismeasured hit position in the module (…too bad) • assumed module position incorrect => we align it • simulated tracks with perfect geometry which is distorted afterwards simulate exactly the same situation for the alignment • exeption: hits at the edge of a module Helge Voss

  4. (Mis)Alignment Elements Alignable Tracker move Dx, Dy, Dz rotate aroundx,y,z,M twist Collection of DetUnits => coherent movements Alignable HalfBarrel move Dx, Dy, Dz rotate aroundx,y,z,M twist/sag..etc Alignable BarrelLayer move Dx, Dy, Dz rotate aroundx,y,z,M twist/sag..etc Alignalbe Rod move Dx, Dy, Dz rotate aroundx,y,z,M twist/sag..etc Alignable DetUnit move Dx, Dy, Dz rotate aroundx,y,z,M Similar: HalfEndcap EndcapDisks Petals DetUnits Helge Voss

  5. (possible?) Alignment Procedure Alignment object sequentially calls: move Barrel move RodLayers move Rods move DetUnits Raw DATA located modules Alignment DB trackfit laserbeam rec. 2 movement/twist HalfBarrel 2 movement/twist BarrelLayers 2 movement/twist Rods 2 movement/twist DetUnits Helge Voss

  6. the “message” • Whatever clever alignment algorithm we might come up with, somehow the displacements will be correlated with to the physical structures. • hierachical structure of displacements in AlignmentDB • testing: apply random (within reasonable limits) displacements within this hierachical structure • test reconstruction efficiency • test alignment procedures Helge Voss

  7. Alignment Tools How are these things realized: Alignable inherits AlignableDetUnit -pointer to DetUnit friend which is allowed to move/rotate the DetUnit - displacements/ position/ orientation w.r.t. the global frame AlignableComposite inherits AlignableTracker A..HalfBarrel A..BarrelLayer A..Rod Helge Voss

  8. CommonDet/DetAlignment Alignable: defines the interface for any alignable object move rotate global position/orientation AlignableComposite: any grouping of Alignable objects knows all its components (not the other way round!) asks component for its global position to calculate the local positions components can moved independently, and don’t need to tell its higher level structure implements coherent move, rotate (rotateInLocalFrame, rotateInGlobalFrame) AlignableDetUnit: the starting bit, seed, leaf….etc performs the actual change of the DetUnit that it points to forwards the position/orientation of the DetUnit as its own one Where is it…. in ORCA Helge Voss

  9. Where is it…. • Tracker/TkAlignment • AlignableTracker • should keep Barrel / Endcap / Pixels…. • AlignableHalfBarrel • AlignableBarrelLayer • AlignableRod • AlignableTest (AlignableDoIt) • instantiates an AlignableTracker • allows to move/rotate it or its pieces • print positions (before after) • call it before the track reconstruction => misalignment • almost as far as to allow playing around with it but rotations still go wrong Helge Voss

  10. Things To Mention • Marumi started implementing the EndCap within this framework • center of the alignable objects do not reflect their physical mountings (e.g. quasi-isostatic mounts) • want to do it now? • will be a lot easier once the geometry database exists Helge Voss

  11. Things To Do • fix and clean up • more individual movements (twist, sag) • some easy intermediate “database” for the testing • correlation between objects • e.g. between forward and backward barrel • between inner and outer barrel Helge Voss

  12. Plans • fix and cleanup • introduce misalignments and study effects on track reconstruction and physics • think about: • AlignmentObject (coordinate/facilitate application of movements to Barrel/Layer/Rod/DetUnit etc..) • Alignment Algorithms • AlignmentDB Helge Voss

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