First Observation of Cosmic Rays in the SCT in the Pit
Alessandra Ciocio
From CERN 29.02.2008

SCT first RUN
February 15 we completed the sign-off of SCT endcaps, officially marking the complete sign-off of whole SCT
February 18 to 20 the SCT (barrel) run in ATLAS
Technical RUN mainly to to integrate in the ATLAS readout and control  and prepare for the next ATLAS M6 combined run
A chance to try global ATLAS integration with a large fraction of the real detector cooled and powered.

The RUN
The tests focused first on Integration of SCT into ATLAS run partition
New TDAQ version
The first day, cooling plant shutdown due to a series of problems mainly due to the control system and took 24 h to solve
The second day checking SCT with ATLAS Trigger
1kHz random triggers from CTP
 some evidence of moving BCID mismatch (not understood)
 ECRs ok
 Stop at 33K events due to eventfilter not receiving ECRs
ECR problem (33K event limit) fixed by Thilo (ATLAS trigger)
Tuesday evening and following night was spent to then dedicated to adjust the SCT barrel readout timing for cosmic triggers
Used the scintillator trigger from TRT
in the pit placed on top of ATLAS (on level 8)
TRT sector 13 on and partial sector 7
SCT all 4 barrels (2112 modules) except 3 cooling loops (~ 150 modules)
No EC - barely enough C3F8 for all but focus on integration instead of bringing in endcaps too (and risking to fall below threshold)

The RUN - (contŐd)
Tuesday night
Switch to scintillator (cosmics) trigger
TRT already seeing tracks
Started timing scan
Accelerate timing adjustment by using signal threshold of 1.2fC
Gradually shift SCT timing and watch for tracks on event display!
Wednesday morning 20 Feb
 realized timing probably just out of range of SCT timing range
 added 3 clock delay in CTP
 fixed SCT BCID FE/ROD mismatch
 synch fully with CTP and TRT
 started seeing tracks in final time bin
the first cosmic tracks were reconstructed in SCT and TRT within hours.

Statistics
Track reconstruction
3 hits
Used in analysis 5 hits
Events 180 / 1255
Tracks
130 (without quality cuts)
102 (more than 5 hits)

Residuals
Residuals from SR1 cosmic2006
Residual distribution by layer obtained with the Global c2 method
Distribution in blue is after applying alignment correction

Space Point multiplicity as function of event number for run 39288
And 2 modules that are noisy for a short period due to HV trips

For M6 (March 3-10)
MinBias likely to fire if number of space points is > 40
Need to go find problematic modules (noisy, space point, flagged errors)
Recalibrate
Reconfigure DAQ
Upgrade On-line monitoring
Etc. etc.
SCHEDULE
Monday standalone run
Tuesday integration in ATLAS and COSMIC RUN with TRT
Thursday HLT run
Friday until Monday morning ATLAS COMBINED RUN
SCT only Barrel, no EC

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