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Latest News

Latest News from VeloAlign

16/10/2009 : Preliminary results of the module alignment with October 09 data has been presented, slides

13/10/2009 : A total of about 20 thousands tracks induced by LHC beam have been reconstructed during last night of data taking. The VELO is under vacuum and it was in the close position. For the first time, tracks in overlap region should be reconstructed.

03/09/2009 : Results of sensor and module alignment with June 09 data has been presented, slides

10/07/2009 : First results of the full procedure (sensor, alignment, 2 half alignment) with June 09 data has been presented, slides

10/07/2009 : First results of the full procedure (sensor, alignment, 2 half alignment) has been presented, slides

07/07/2009 : A paper on the first alignment results has been submitted to Nucl. Instr. and Meth. A

06/06/2009 : A total of about 50 thousands tracks induced by LHC beam have been reconstructed during this weekend of data taking. The VELO is under Ne and it was almost in the close position (2 mm and 2.45 distance between the two half). For the first time the two half alignment has been measured (events: 3, 5, 8, 16 and event movie)

02/06/2009 : A (internal) note on First Alignment of the LHCb VELO and Analysis of Beam Absorber Collision Data has been released is available, note

30/04/2009 : Update in CVS the VELO alignment code, including major improvement in PV method and the new options in python style.

06/04/2009 : Update of the global position in the database, to be used for MC data

12/03/2009 : Alignment results have been presented at the 1st international conference on Technology and Instrumentation in Particle Physics (TIPP09), slides

09/03/2009 : Presentation on the monitoring of 2 half alignment using the PV, slides

17/02/2009 : Presentation of the final results of alignment obtained from beam induced tracks at the LHC, slides

12/03/2009 : Presentation on the alignment monitoring, , slides

12/12/2008 : A (internal) note on Initial LHCb VELO Alignment from Survey Measurements has been released is available at link

12/11/2008 : Presentation of the alignment results obtained from beam induced tracks at the LHC, slides

06/09/2008 : A total of about 1500 tracks induced by LHC beam have been reconstructed during the second weekend of data taking.

24/08/2008 : A first alignment of the LHCb VELO has been obtained from beam induced tracks at the LHC (about 700 tracks were reconstructed), link

22/08/2008 : First reconstructed tracks induced by LHC beam in the VELO (5 modules on for each side): First event, Nature article

31/07/2008 : Alignment papers published:
For the alignment method:
S. Viret, C. Parkes, M. Gersabeck, "Alignment procedure of the LHCb Vertex Detector", Nucl. Instr. and Meth. A596 (2008) 157-163

For the beam test results:
M. Gersabeck, S. Viret, C. Parkes et al. (the LHCb VELO group), "Performance of the LHCb Vertex Detector Alignment Algorithm determined with Beam Test Data", Nucl. Instr. and Meth. A596 (2008) 164-171

11/06/2008 : Presentation about survey implementation of 2008 data geometry, slides

09/04/2008 : The draft of the note on the sensor alignment method was added to the application section.

07/04/2008 : The survey measurements have been included in to the condition database.

28/03/2008 : Presentation about final VELO metrology, slides

19/03/2008 : Two paper drafts were added to the application section. One paper describes the alignment methods and the other the results from the ACDC3 test beam.

25/01/2008 : Presentation about the VELO alignment status, slides

23/01/2008 : The VELO sensor alignment code has been added to CVS as part of the Alignment project. Source code released as VeloAlignment v4r0, full implementation to be released in Alignment v2r4.

01/10/2007 : The VELO sensor resolution results have been summarised on the ACDC3 results page as section C9.

04/09/2007 : Large updates in the application section, in particular concerning new method for producing misaligned events. ACDC3 results page has also got some update, new plots concerning crosstalk.

03/07/2007 : The ACDC software page has been updated, now with explanation on how to run the alignment. ACDC3 results page has also undergone some important update, lots of new nice results here. A draft of the latest Velo Alignment note (box alignment) is available at the end of the application page.

25/06/2007 : The Links have been updated with some information about LHC Detector Alignment Workshops.

18/05/2007 : The ACDC software page has been updated. It now explains how to run the alignment on emulated data.

02/05/2007 : The application page has been largerly updated. In particular, latest and final results on the box alignment are presented. An internal note on VELO overlaps, prior to the box alignment note, has been released and is available here.

07/03/2007 : The C++ standalone code has been updated in order to follow the improvement of the software released on LHCb CVS. The major change concerns the generalisation of the treatment of non-linear terms in Millepede. Main changes thus affect Millepede and MilleTool classes.

05/03/2007 : The documentation of the MC study of sensor misalignment has been added as section 2.C9.

28/02/2007 : The recipe for producing and analysing misaligned events has been updated to DC06 software on the 'Application to Velo' pages 2.F and 2.G.

17/01/2007 : A first look at sensor/sensor misalignment, using an enhanced toy based on the standalone code, is presented at the end of the internal alignment page.

09/01/2007 : A new page presents the lastest ACDC3 results.

13/12/2006 : Two parts have been slightly updated. C++ code has been optimized and debugged. A new recipe for running the alignment on ACDC3 data using Vetra v3r1 is available here.

11/10/2006 : Started a serie of pages dedicated to the 2006 system tests (aka ACDC). These pages could be accessed via the application page. For the moment there is one part on how to run the alignment on ACDC data, using VETRA, and one page on ACDC2 preliminary results.

01/08/2006 : How to generate misaligned events part has been updated and is now compatible with DC06 production versions (hopefully Gauss and Boole versions are the good ones this time...). Also few cosmetics changes in the page presentaion.

27/07/2006 : New part in the application area. This section is providing information on how to use the Velo Alignment Software. This is a first version, which is suppose to evolve constantly.

23/07/2006 : Very large update of the application area, with latest results on internal alignment, and first results on overlap alignment. ACDC3 preliminary studies are also displayed.

07/06/2006 : How to generate misaligned events part has been updated and is now compatible with DC06 production versions. A prospective (internal) note on Kalman filtered alignment in the VELO has been released. It's available here with usual login and password.

01/05/2006 : Box alignment results have been updated. First results on the tilts and improved results on the offsets are shown (no more k factor problem...)

13/04/2006 : The standalone code has been corrected and updated. Concerning the correction, bug in the global derivatives assignment has been corrected (now we take the slopes of the misaligned track, not the perfect one). Concerning the updates, an improvment for non-linear approach has been added to the code. More parameters could be tuned in constants.h. Tracks are now coming from the same primary vertex.

04/04/2006 : The part on how to generate a misaligned set of events has been updated in order to work with LHCb v20r1 version. This has been tested up to BOOLE. Click here to learn more about that. LHCb note is now public and available here.

28/02/2006 : A standalone alignment example, using the latest C++ version of Millepede, is now available here. You could also access it from the left menu, by clicking on C++ code.

23/02/2006 : Update on how to generate a misaligned set of events in application area. The part has been updated in order to work with Gauss v22r1, ie the last version before LHCb v20r0 switch.

16/01/2006 : Note LHCb-2005-101 is now released on CDS, available as public soon. Links section also updated.

12/12/2005 : Updated version of the software alignment note. This note is dedicated to internal alignment of the VELO modules within the boxes. More info available in the application area.

20/11/2005 : A large update has been performed in the Application section. In particular, first results on box alignment using data misaligned via the geometry framework are presented. Other small update in the Constraints section (new values for the boxes accuracies).

14/11/2005 : A new page in the application area, giving some informations on how to produce misaligned event using the LHCb geometry framework. Click here to go there. Results will arrive soon.

28/10/2005 : A first draft of the VELO online alignment note is now available for comments in the application area.

05/10/2005 : Update on step 2 in the application area. Final result is getting a little bit better now.

04/10/2005 : Update on step 1 in the application area. Plots describing internal alignment effect on residuals have been produced. Links section has also been a little bit updated.

09/09/2005 : Updates in the application area. In particular, first results on step 2 are presented.

06/09/2005 : Alignment status and testbeam implementation milestones presented during Velo Software Review.

01/09/2005 : Effect of VELO misalignments on proper time estimation. Talk given during LHCb ProperTime & Mixing working group meeting.

28/08/2005 : First informations concerning Alignment code implementation under GAUDI. Go here. Results and comparison plots coming soon.

24/08/2005 : A draft of the note concerning Misalignment studies is available here . Results concerning robustness tests have been updated, also concerning the halo tracks. All infos on the dedicated application area . Links also updated.

04/07/2005 : Large update of the application area. New results concerning the first robustness tests.

08/06/2005 : Alignment status presented, new results (Step 1 with bbar events) and ideas (using halo tracks for Step 1) are described in the application area. Also a small update of the Alignment Techniques page.

24/05/2005 : Alignment algorithm presented during Software week.

14/05/2005 : Alignment page complete refurbishment. Take the occasion to update some parts, correct some errors. In particular, Application page was updated with the first step 2 results.

10/05/2005 : A simple example of Millepede C++ code available on the web. There will be an access to this page with classic LHCb code as soon as possible. For the moment, just ask me the web adress if you're interested.

09/05/2005 : T-Rec meeting mainly dedicated to alignment issues. 4 talks entirely dedicated to alignment in tracking detectors and software framework.

29/04/2005 : Alignment status presented during VELO software meeting. As usual, talk is available on the agenda.

18/04/2005 : Problem seen on the forward right part corrected, results have been updated.

08/04/2005 : Large update in the Application section. First results with Millepede.

14/03/2005 : The Application page has been started. Links were also updated.

18/02/2005 : Alignment techniques page updated (links to talks on Millepede added).

18/02/2005 : Talk on alignment status given at the VELO Software meeting. Talk could be accessed from the agenda.