A. De Caro for the ALICE TOF Offline Group (University of Salerno and INFN)

Some results obtained with the analysis of the data taken during the cosmic runs (12/07-09/08) with/without L3 magnetic field.

Analysis of the cosmic run data During last summer, we worked to the analysis of the data taken during the cosmic runs and we updated the TOF code according to this analysis results. After: noise study, correction of time measurements per cable delays, correction of time measurements per some found offsets; correction of the maximum distance-approach of a reconstructed tracks to a matchable TOF hit pad (one of the recoParams), we successful reconstructed some events. October 21th 2008ALICE Offline Week A. De Caro 3

Cosmic muon reconstructed in ALICE detector (B=0 T) t1 t2 t1<t2 Muon direction TPC clusters TRD clusters TOF clusters Reconstructed track ALICE Offline WeekOctober 21th 2008 A. De Caro 4

Prospective view ALICE Offline WeekOctober 21th 2008 A. De Caro 5

t1 t2 t1<t2 Muon direction B = - |B| k -- Cosmic muon reconstructed in ALICE detector (B=0.5 T) ALICE Offline WeekOctober 21th 2008 A. De Caro 6

A. De Caro 7 -- Prospective view ALICE Offline WeekOctober 21th 2008 A. De Caro 7

To check the functionalities of the alignment algorithm with real events

Distance-approach (  -z view) First alignment step for the TOF detector: along the beam direction (z axis). Distance-approach: the distance between the impact point of the reconstructed track on the TOF strip and the centre of the closer TOF cluster (schematically shown here). The z component of the distance-approach is the parameter used to align TOF SMs along z axis.  =371 cm Reconstructed track ALICE Offline WeekOctober 21th 2008A. De Caro 9

Distance-approach distributions (B=0 T) -1- ALICE Offline WeekOctober 21th 2008 A. De Caro 10

Distance-approach distributions (B=0 T) -2- ALICE Offline WeekOctober 21th 2008 A. De Caro 11

Distance-approach distributions (B=0 T): aligned geometry -1- ALICE Offline WeekOctober 21th 2008 A. De Caro 12

Distance-approach distributions (B=0 T): aligned geometry -2- ALICE Offline WeekOctober 21th 2008 A. De Caro 13

Distance-approach vs strip per TOF SM (B=0 T) ALICE Offline WeekOctober 21th 2008 TPC: field cage internal wall A. De Caro 14

Distance-approach vs strip per TOF SM (B=0.5 T) ALICE Offline WeekOctober 21th 2008 TPC: field cage internal wall Caused by a not corrected calibration for the drift velocity (TPC people confirmed). A. De Caro 15

I would like to understand why I didn’t receive answer… on Marian.Ivanov: do you know how often it is necessary to update the TPC reco parameters (gain factor, as example)? on Marian.Ivanov and on Marek.Kowalski (who forwarded this to Marian.Ivanov): …I noted also that there was a 'strange' trend for DeltaZ paramenter, that is the distance along the beam direction between the reconstructed track and the matched TOF sensitive element. In particular, I can see the following trend: | DeltaZ | ~ a * z + b where a and b parameters assume different values for z 0 (practically, at z=0, there is an offset between the two lines found for z>0 and z<0). Maybe you find similar results... For this I am sending you this . I hope you can give me more details about. October 21th 2008ALICE Offline Week A. De Caro 16

Geometry overlaps in the following cases: Ideal misalignment Residual misalignment Full misalignment TOF survey alignment object: we have one of them only recently inserted in the DCDB but we have to check the code with this object. October 21th 2008ALICE Offline Week A. De Caro 17 OK To be checked See next slide

FSTR/FTLA and FSTR/FLTC extrusions October 21th 2008ALICE Offline Week A. De Caro 18

FSTR/FTLA and FSTR/FLTC extrusions October 21th 2008ALICE Offline Week A. De Caro 19 FTSR25FTSR29FTSR63 FTSR67

SM16 SM8 SM0 SM10 SM1 SM9 SM17 SM7 ESD track selection conditions October 21th 2008ALICE Offline Week 22 0cm<y 0 <65cm 10°<  <30° 0cm<y 0 <65cm 150°<  <180° -65cm<y 0 <0cm 150°<  <180° -65cm<y 0 <0cm 10°<  <30°

TOFforTRD trigger E. Scapparone, Physics Forum, 2nd July 2008 October 21th 2008ALICE Offline Week 23 SM7&&SM17 SM8&&SM16 SM1&&SM9 SM0&&SM10