1 First Considerations on LNF Tier2 Activity E. Vilucchi January 2006

2 Hypothesis LNF Tier2 Computing Resources [1] : Resources Use: 30% resources for SIMULATION 30% resources for ANALYSIS 30% resources for CALIBRATION Anno CPU (KSI2K) Work. Node Disk (TB) Power Elec. (kW) Racks numb

3 CPU Increment

4 Disk Increment

5 Work Proposal [2] Year Simulation (10^6 Events) Analysis (Users) Residual CPU for calibration (KSI2K) Residual Disk Space for calibration (TB)

6 Simulated events Keeping data in the Tier2 for one year

7 User analysis supported

8 Calibration [3] Proposal for calibration and alignment of: Muon groups of Michigan, Munich, Rome (La Sapienza, Roma Tre), Saclay; October Work subdivision: CERN: splits data in sub-streams (not stored): barrel, end-caps, alignments; Tier1: stores data on tape and sends them to Tier2; University of Michigan: spectrometer end-caps; Munich: spectrometer barrel and alignments tasks; Rome (La Sapienza and Roma Tre): spectrometer barrel;

9 Data Requirements for all calibration centre : t 0 computed weekly: ~20000 muons hits per tube, therefore ~ 10^8 muon tracks each day. Since 1 muon track is  1 KB (while 1 event  1.6 MB), then  100 GB per day; r-t computed daily: the same data collected for the t 0 computation; Alignment parameters updated every 2-4 hours: 2x10^6 muon tracks; negligible w.r.t. 10^8. Calibration and alignment validation: internal consistency of t 0 and r-t functions (still under study) and physical checks with a small fraction of ATLAS data stream (~10^5 events/day: 100 CPU h./day 200 GB/day). Computing requirements for all calibration centre: CPU for calibration: 0.2 s/track  0.2X10^8 sec per day  6000 h. per day  300 processors  300 KSI2K of CPU per day; CPU for alignment: 1 s/track  2X10^6 sec per day  0.2X10^7 sec per day, negligible w.r.t. CPU for calibration; 300 GB of disk space per day. If it is maintained for 1 mounts: 9 TB of disk space;

10 Human resources per calibration center: Supervision of transfer process, functioning of transmission links and reaction to errors: 0.5 FTE; Program running and debugging of calibration software: 0.25 FTE; in centers responsible for alignment tasks: 0.45 FTE; Maintenance and update of calibration software: 0.5 FTE; for alignment task: 0.5 FTE in more; Calibration, alignment and validation: 2-3 FTE (detector or analysis experts). After some experience human resources can be replaced by automated systems and these estimates can be relaxed.

11 References 1.Progetto di massima Centro Tier2 ATLAS LNF; M. L. Ferrer, M. Pistoni), 2005; 2.ATLAS Computing Technical Design Report; ATLAS Computing Group, ATLAS TDR—017, CERN-LHC , July 2005; 3.“A proposal for the calibration alignment of the ATLAS muon spectrometer”; P. Bagania, O. Biebel, C. Guyot, H. Kroha, D. Orestano, B. Zhou, October 30, version 2.