1. SSD STATUS Enrico Fragiacomo – INFN Trieste

2. Outlook  MC-data comparison  Cluster finder  dE/dx  Material budget in geometry ITS alignment&offline - CERN 4/29/2010 2

3. MC-data #recpoints ratio mod-by-mod 900 GeV sim pp and real data from run 104799 p0: 1.02244 +/- 0.0119124p0: 1.01755 +/- 0.0109631 Strongly depends on sim production and run dates! See later… Ramona L. ITS alignment&offline - CERN 4/29/2010 3

4. MC-data recpoints ratio lad-by-lad Selected modules from previous slide removed! ITS alignment&offline - CERN 4/29/2010 4

5. MC-data bad channels ratio V2 map in OCDB before March, 31th V3 map in OCDB after March, 31th Run 114786 from March, 30th ITS alignment&offline - CERN 4/29/2010 5

6. MC objects: BadChannelsSSD & NoiseSSD updated on March 31 st Used from LHC10b1 (run 114786) GainSSD updated on February 22 th Globally (fixed map): BadChannels on Pside: 10.81% BadChannels on Nside: 8.92% DATA objects: BadChannelsSSD & NoiseSSD updated at each Physics fill (~daily) GainSSD updated on February 22 th Possible relevant run-by-run fluctuations in DATA of the BadChannels number : module #1548 – P side: completely off in some runs fluctuation in ~30 module-Psides on Layer6 (sensitive to humidity): hundreds of channels can be off in some runs (128ch =1/6 module-side) statistical fluctuation (3 σ -noise cut for BadChannels) Globally (April2010 distribution): BadChannels on Pside: 10.92% - RMS = 0.07% BadChannels on Nside: 8.94% - RMS = 0.01% Data-MC consistency in Calibration Objects Mino C. ITS alignment&offline - CERN 4/29/2010 6

7. DIFFENCE BETWEEN BAD CHANNELS (Simulation-Data) MOD 1010: p-side sintef noise -> not insulated MOD 1608: p-side sintef noise -> not insulated MOD 1618: p-side sintef noise -> not insulated 1010 1608 1618 1548 MOD 1548: P-side off in some runs SSD Numeration (0 - 1698) V3 sim and data from run 114918 ITS alignment&offline - CERN 4/29/2010 7

8. DIFFENCE BETWEEN BAD CHANNELS (Simulation-Data) SSD Numeration (0 - 1698) 635 MOD 635: n-side very low noise -> tagged as 'dead' in the calibration run used for the simulation but alive during the data taking! V3 sim and data from run 114918 ITS alignment&offline - CERN 4/29/2010 8

9. Summary (1/2)  All modules with ratio 1.2 have been checked  Almost all of them reflect a different condition in the DATA-MC OCDBs.  For the other smaller discrepancies: the spikes above 1 correspond in most of the cases to the last module in a ladder (position 22).  Structures on the half-ladder basis: in many cases the A- side half-ladder has a lower ratio with respect to the corresponding C-side half-ladder. Mino C. ITS alignment&offline - CERN 4/29/2010 9

10. Summary (2/2)  9 modules with ratio < 0.8:  1 P-side off in some runs (2048)  6 P-side noisy (strips not insulated) (2108,2118,1510,1506,1629,1860)  2 modules with very low noise on one side--> tagged as bad (525, 1135)-->probably to include back!  1 module with ratio > 1.2  always good about noise, many channels masked because of old defects, now recovered (1154) --> to include back!  general:  module in position 22 always higher ratio (~1.1)  module in position 1 often lower ratio  A-side lower ratio wrt C-side ITS alignment&offline - CERN 4/29/2010 10

11. Cluster finder  Activity ongoing on the cluster finder optimization (Sasha B.+EF): 1. some small fixes in the clusterization 2. tricks to speed it up (as suggested by the HLT), 3. eta distribution ITS alignment&offline - CERN 4/29/2010 11

12. dEdx MPV as function of module number for different 7TeV runs and pass6 of 900 GeV. Main conclusion: The gain looks to be stable in time but there are few bad modules which have huge fluctuation on gain. They are under investigation Marek C. ITS alignment&offline - CERN 4/29/2010 12

13. Bad channels ITS alignment&offline - CERN 4/29/2010 13

14. Material distribution from conversions Savannah 63965F. Bock SDD, SSD show 10-20% more conversions than expected SPD situation unclear; depends on V0 finder? 14

15. Labeling conversions in MC Added code in AliITSv11Hybrid::StepManager to histogram conversions 15

16. Material SSD Main contributions: Sensor (42%), ladder cables (18%), spaceframe (8.5%), cooling tubes+water (7.8%) Table from design: ITS alignment&offline - CERN 4/29/2010 16

17. Main missing components Cross-checked contributions in MC with table, good agreement found All large contributions accounted for Few small parts missing: metal caps on capacitors + solder, approx. 0.18 g per module (out of 2.66 g per module, 6.371 g ladder segment) 0.05 % X/X 0 out of 0.876 % total Added to MC, not committed yet. Will reduce discrepancy 17

18. Latest news  The main update is that everything has now been committed to AliRoot trunk. The changes are: 1. inclusion of metal endcap of capacitors+solder 2. change of density carbon-fiber 1.6 -> 1.8, also for support cone. 3. some small changes to ladder cables: increase in kapton, decrease Al, accroding to measurements Ton; net effect of this is probably negligible. ITS alignment&offline - CERN 4/29/2010 18