# Presentation: 549009

## 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.

- 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

- 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

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