1. TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, 07-Jun-20081 TRD alignment with (German) cosmics Dariusz Miśkowiec (GSI), Eva Sicking (Uni Münster) ALICE offline week, 8-Jul-2008 intro alignment with Münster cosmics

2. TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, 07-Jun-20082 alignable objects in TRD 18 TRD supermodules like /TRD/sm03 aligned by survey 540 TRD chambers like /TRD/sm03/st3/pl0 aligned with tracks

3. TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, 07-Jun-20083 Münster cosmics Bastian Bathen cosmic trigger rate 100 Hz 1 M – 10 M events per SM 100 k – 1 M tracks per SM phi

4. TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, 07-Jun-20084 scintillator paddles for cosmic trigger TRD supermodule

5. TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, 07-Jun-20085 Münster cosmics in this talk: 5370 tracks in SM4 (now in sectior 9) btw. data looks like coming from sector 0 supermoduleassembledreassembledinserted SM1Heidelberg---Nov(?) 2006 Sector 8 SM2Münster---Jan 2008 (?) Sector 0 SM3Münster SM4MünsterCERNMay 2008 Sector 9 SM5Münster May 2008 Sector 17

6. TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, 07-Jun-20086 Münster cosmics, SM4 ALICE pit top viewALICE pit view from A-side

7. TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, 07-Jun-20087 Münster cosmics, SM4 ALICE pit top viewALICE pit view from A-side

8. TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, 07-Jun-20088 Münster cosmics, SM4 ALICE pit top viewALICE pit view from A-side

9. TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, 07-Jun-20089 alignment procedure with AliAlignmentTracks AliAlignmentTracks AliTrackPoints.root PointSelector.C AliESDs.root AliESDfriends.root AliAlignOb j AliTrackFitter (Straight, Rieman) AliTrackResiduals (Chi2, Fast, Linear)

10. TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, 07-Jun-200810 alignment procedure L5 L4 L3 L2 L1 L0 keep L0 and L5 fixed adjust inner ones to all (at least 4) others (iteratively) fit straight tracks use "fast" minimizer (all 6 shifts and tilts allowed)

11. TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, 07-Jun-200811 Münster cosmics, SM4 SM4, stack 1

12. TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, 07-Jun-200812 Münster cosmics, SM4 SM4, stack 2

13. TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, 07-Jun-200813 Münster cosmics, SM4 SM4, stack 3

14. TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, 07-Jun-200814 How many tracks per stack are needed? this was with 1000 tracks tested 200,1000, 2000 2000 much better (flatter) than 1000

15. TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, 07-Jun-200815 Münster cosmics, resolution residuals datasetwhat aligned to what peak width Münster cosmics L3 L0,L1,L2,L4,L50.30 cm sim v4-11-ReleaseL3 L0,L1,L2,L4,L50.18 cm sim v4-11-ReleaseL0 TPC0.22 cm sim v4-11-ReleaseL5 TPC0.80 cm sim v4-06-ReleaseL3 L0,L1,L2,L4,L5 0.07 cm sim v4-06-ReleaseL9TPC0.11 cm

16. TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, 07-Jun-200816 Münster cosmics, summary chamber alignment very good (typically within 0.5 mm) 1000-2000 tracks per stack reasonable for alignment residuals 1.7 times wider than in simulation residuals with tracklets 2.2 times wider than with cluster

17. TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, 07-Jun-200817 backup

18. TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, 07-Jun-200818 Münster cosmics, SM4 SM4, stack 0

19. TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, 07-Jun-200819 Why resolution worse than in sim? Might be because of the tail Xe tail cancellation applied to Ar. In this case, however, phi-dependence expected. Not seen (Eva): width of the residuals btw., different groups of tracks give within 0.1 mm the same alignment

20. TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, 07-Jun-200820 Münster cosmics, why poor resolution? Might be because of the track cuts, wide open for cosmics and B=0 Under investigation by Eva.

21. TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, 07-Jun-200821 Münster cosmics, SM4