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

3

MC-data #recpoints ratio mod-by-mod

900 GeV sim pp and real data from run 104799

p0: 1.02244 +/- 0.0119124 p0: 1.01755 +/- 0.0109631

Strongly depends on sim production and run dates! See later…

Ramona L.

ITS alignment&offline - CERN 4/29/2010

4

MC-data recpoints ratio lad-by-lad

Selected modules from previous slide removed!

ITS alignment&offline - CERN 4/29/2010

5

MC-data bad channels ratioV2 map in OCDB before March, 31th

V3 map in OCDB after March, 31th

Run 1

14786 f

rom

Marc

h,

30th

ITS alignment&offline - CERN 4/29/2010

6

MC objects: BadChannelsSSD & NoiseSSD updated on March 31st

Used from LHC10b1 (run 114786) GainSSD updated on February 22th

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 22th

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 (3σ-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

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

101016081618

1548

MOD 1548: P-side off in some runsSSD Numeration (0 -

1698)

V3 sim and data from run 114918

ITS alignment&offline - CERN 4/29/2010

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

9

Summary (1/2)

All modules with ratio <0.8 and >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

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

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

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

14

Material distribution from conversions

Savannah 63965 F. Bock

SDD, SSD show 10-20% more conversions than expectedSPD situation unclear; depends on V0 finder?

15

Labeling conversions in MCAdded code in AliITSv11Hybrid::StepManager

to histogram conversions

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

17

Main missing components

Cross-checked contributions in MC with table, good agreement foundAll 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/X0 out of 0.876 % total

Added to MC, not committed yet. Will reduce discrepancy

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+solder2. 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