Alignment constants for first data

Note: most of the sets with alignment constants below can be found in /afs/ To load a particular set, use the following:

     from Configurables import ( CondDB, CondDBAccessSvc )
     alignDBLayer = CondDBAccessSvc( 'AlignDBLayer' )
     alignDBLayer.ConnectionString ='sqlite_file:/afs/'
     CondDB().addLayer( alignDBLayer )

The latest constants for field on and off are:

  • LATEST FIELD ON: v3.0.db
    • Tag: not yet tagged
    • Description: fixes the velo half alignment, realigns TT, IT and OT * Velo-halves: Tx, Ty, Rx, Ry with millepede * TT-modules, IT ladders, OT modules

  • LATEST FIELD ON: v2.3.db
    • Tag: align-20100302
    • Description: like v2.2 but fixing the TT pitch

  • LATEST FIELD OFF: v1.3.db
    • Nickname: v1.3
    • Tag: align-20100302-moff
    • Description: uses the IT ladder / OT module alignment of v2.2, but realigns the boxes and C-frames just as for v1.2. This gives slightly better residuals in IT and OT.

Below are older databases.

  • VeloOTTxTyModulesTxITTxTyRzTTTxFieldOff_20100115.db
    • Nickname: v1.0
    • Tag: LHCBCOND align-20100115
    • Data-set: run 63596
    • IOV: [23/11/2009 - Infty]
    • Description (
      This is the first alignment database obtained with collision tracks. It uses the data from the field-off run 63596. Alignment degrees of freedom were:
      • Velo-global Rx
      • Velo-right-half Ry
      • TT-halflayers Tx
      • TT-Boxes Tx, Ty, Rz
      • OT-CFrames Tx, Ty
      • OT-Modules Tx
  • VeloOTTxTyModulesTxITTxTyRzTTTxFieldOffTTLaddersFieldOn_20100122.db
    • Nickname: v1.1
    • Tag: LHCBCOND tt-20100129
    • Data-set: run 63596 and some magnet on data
    • IOV: [23/11/2009 - Infty]
    • Description (
      Update of TT half module alignment: The alignment DOFs are identical to 20100115, except that TT half modules are added to resolve a large rotations of some TT modules around the beam pipe. This improves V0 efficiency and resolution. The procedure was:
      • start from previous alignment
      • use magnet-on data to align all global structures plus TT internally
      • take resulting TT module alignment, and fix TT global parameters on field-of run 63596 The resulting database only differes from 20100115 in the TT alignment.
  • VeloOTTxTyTzModulesTxITTxTyTzRyRzTTTxFieldOffTTLaddersFieldOn_20100205.db
    • Nickname: v1.2
    • Tag: not for release
    • Description: same as above, but now adding more degrees of freedom:
      • Velo-global Rx
      • Velo-right-half Ry
      • IT boxes: Tx, Ty, Tz, Ry, Rz
      • OT C frames: Tx ; OT C-frame A/C-pairs: Ty Tz
      • OT-Modules Tx
      • Velo-global Rx
      • Velo-right-half Ry
      • TT: Tx Ty Tz
      • TT-halflayers Tx
      • TT-Boxes Tx
        Furthermore, the OT survey was fixed for the bowing of the bridge that was measured in the IT survey. Also the errors on the OT module survey were tightened in order to stay a bit closer to the ideal geometry. This database isn't really any better than the previous but was the starting point for the magnet-on alignments. it works poorer on magnet-on data. * VeloOTTxTyTzModulesTxITTxTyTzRxRyRzTTTxTTLaddersFieldOn_20100211.db
    • Nickname: v2.0
    • Tag: not yet uploaded
    • Description: this is the first FIELD-ON alignment. On field-on data this database gives 30% better IT residual distribution, better overlap between IT stacks, and better matching between T and Velo, and T and CALO, Starting from the alignment of 20100205, the following dofs were aligned:
      • IT boxes: Tx, Ty, Tz, Rx, Ry, Rz
      • OT C frames: Tx ; OT C-frame A/C-pairs: Ty Tz
      • TT: Tx Ty Tz
      • TT-halfmodules: Tx
        IT and OT were fixed in T3
  • VeloOTTxTyTzModulesTxRzITTxTyTzRyRzITLaddersTxRzTTTxOffTTLaddersFieldOn_20100212.db
    • Nickname: v2.1
    • Tag: not yet uploaded
    • Description: like above, but adding IT ladder and OT modules (both Tx and Rz). This databases gives a few % improvement in the residuals in IT and OT. * v2.2.db
    • Tag: align-20100302
    • Description: like v2.1 but without the realignment of Ty for IT boxes. this solves a problem in the IT overlaps.

  • alignment of IT boxes using TED data
    • input: TED2 data
    • parameters:
    • xml
  • alignment of VELO using TED data
    • input: TED2 data: runs 32474-32586, ~1900 events, about ~800 tracks
    • parameters: Tx and Ty of all modules; constraints: average position and shearing for both halves
    • xml:
  • alignment of TT using VELO-TT tracks in TED2 data
    • input: TED2 data: runs 32474-32586, ~1900 events, about ~800 tracks
    • parameters: Tx of all layers
    • xml
    • note: granularity (full layers) does not necessarily makes sense.
  • alignment of OT half-layers using cosmics (millepede)
    • input: runs 34120,31225,31557,34083,34117, ~31k events (stripped DSTs from Wouter), ~19k tracks
    • parameters: Tx of all half layers. first and last two layers fixed.
    • xml

Alignment constants for MC studies

  • For the velo misalignment challenge, you can find a sqlite layer here
    and the result after running the alignment software here (under the tag
  • A slice for MisAlCh1 you can find here
    Marco Clemencic has kindly extracted thisd layer from the original xml database at
        /castor/ (DON'T USE)
  • For the IT/OT alignment with the alignment framework, Matt's page has many xml files, both for the input and ouput of the alignment challenge
  • There is an sqlte layer for "Tx,Rx,Rz" aligned IT ladders and OT modules here
    (It would be nice to describe what went into this.) The interesting thing about this one is that the system after the magnet was not constraint in Tx. Therefore, it has an rather large (~1mm) global displacement in x leading to a significant q/p bias.

Tips and tricks for creating alignment databases

On this page we collect xml files and sqlite layers for various (mis)alignments.

How to create sqlite from the xml

To create an sqlite data base from a set of xml files, you can follow this recipee.

  • first creat an directory that will hold the data files, e.g. MyDBLayer
  • now copy the xml files to the right place, depending on subdetector:
    • for OT: MyDBLayer/Conditions/OT/Alignment/Elements.xml
    • for IT: MyDBLayer/Conditions/IT/Alignment/Detector.xml
    • for VELO constants are split over 3 files
      • global and halves: MyDBLayer/Conditions/Velo/Alignment/Global.xml
      • modules: MyDBLayer/Conditions/Velo/Alignment/Modules.xml
      • sensors: MyDBLayer/Conditions/Velo/Alignment/Detectors.xml
  • now go to the directory that contains MyDBLayer and create the sqlite database with
      shell> SetupProject LHCb
      shell> -c sqlite_file:MyDBLayer.db/LHCBCOND -s MyDBLayer

How to load an sqlite 'layer'

This is how you can load it in python

MisAlCh1COND = CondDBAccessSvc("MisAlCh1COND")
MisAlCh1COND.ConnectionString = "sqlite_file:VeloSliceMisaligned.db/LHCBCOND"

The recipee for doing this in job options is something like this

CondDBDispatcherSvc.Alternatives = {'/Conditions=CondDBLayeringSvc/CONDLayers'};
CONDLayers.Layers = {'CondDBAccessSvc/CONDLocal', 'CondDBAccessSvc/LHCBCOND'};
CONDLocal.ConnectionString = "sqlite_file:$HOME/VeloSliceMisaligned.db/LHCBCOND";

(See this twiki topic.)

How to extract the xml from an sqlite database

See here

How to load xml files directly

-- WouterHulsbergen - 30 May 2008

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Topic revision: r16 - 2010-04-27 - WouterHulsbergen
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