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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
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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 largefraction of the real detector cooled and powered. A. Ciocio
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) A. Ciocio
The RUN - (cont’d) • 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. A. Ciocio
Statistics • Track reconstruction • 3 hits • Used in analysis 5 hits • Events 180 / 1255 • Tracks • 130 (without quality cuts) • 102 (more than 5 hits) A. Ciocio
Residuals A. Ciocio
Residuals from SR1 cosmic2006 • Residual distribution by layer obtained with the Global 2 method • Distribution in blue is after applying alignment correction A. Ciocio
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 Mask 1 continuously noisy module due to HV line broken A. Ciocio
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 A. Ciocio