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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Slide 15 |