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ESPERIENZA di Commissioning a CDF

ESPERIENZA di Commissioning a CDF. Anna Maria Zanetti INFN Trieste. Bologna - 23 Novembre 2006. CDF. Run I : first data in 1985 ( prehistoric organization & detector)  not too much to learn. ( L~ 2 x 10 31 cm -2 s -1 )

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ESPERIENZA di Commissioning a CDF

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  1. ESPERIENZA di Commissioning a CDF Anna Maria Zanetti INFN Trieste Bologna - 23 Novembre 2006

  2. CDF Run I : first data in 1985 (prehistoric organization & detector)  not too much to learn. (L~ 2 x 1031 cm-2 s-1 ) Run II: Official Start march 2001: almost New Detector! (10-20xLrunI) From CDF I: solenoid, central calorimeter, part of muon system All the rest is NEW! • Endplug Calorimeter • Tracking -Silicon:SVXII,ISL,Layer00 -Central Outer Tracker • Front End Electronics • Trigger • DAQ System • Muon systems • TOF • Offline/Online Software

  3. La Sfida di LHC La SFIDA di LHC Energy: 14 TeV = 7 x Tevatron Length: 27 km = 4 x Tevatron Magnetic Field: 8.3 T = 2 x Tevatron Beam Energy: 350 MJ = 250 x Tevatron Bunch Collisions: 40 MHz = 20 x Tevatron Instantaneous Luminosity = 60 x Tevatron # of Collisions in an event = 10 x Tevatron # of Detector Channels: 100 M = 100 x Tevatron # of Scientists (~2500/expt) = 3 x Tevatron Tevatron: proton-antiproton 7 accelerators LHC: proton-proton LHC

  4. Commissioning CDFII …but 2002 still struggling with fully commissioning some detectors/electronics/software and with problems in detectors and Beam.

  5. First Phase: Late 1999-2000 CDF non yet completed • Integration of components into DAQ • Daily running – pedestals, calibration runs • November 1999: Three system readout test (DAQ w/ multiple readout systems: Calorimeter/TDC/Si DAQ • January 2000: L1 calorimeter trigger established. Sum Et, Single tower, Missing Et triggers • Cosmic Ray Running • Once L1 trigger established, begin Timing-in of Electronics • Across all detector subsystems, and across trigger subsystems • Basic Level 3 filtering established • Development of detector monitoring • Calorimeter thresholds/noise rates • A lot of work accomplished in debug and commission all the trigger systems and the Electronics • Essential to be able to inject data/ read your system, test it indipendently by the others and in final environment

  6. Commission Trigger & Electronics A lot accomplished with standalone test(no beam or cosmics): Take Silicon Vertex Tracker (SVT) as example (~100 custom VME boards and a complex task) - but applies to all complex trigger systems. Note:SVT was well thought on testing capability and monitoring the data flow on each board. Probably the best in CDF: • Independency from CDF DAQ (data driven device) • Common data communication protocol • Boards as building bricks that can be combined at will (~lego) • Can adapt SVT configuration to various test needs • Ability to inject/read data from every board • Can test most board functions with no additional hardware • Software with board “objects” (ram, regs…) in common framework Still it was not enough !!! System missing all these-> struggle, building on the fly boards for testing purposes, suffered delays, etc

  7. ..so what was missing? • Plan for lack of input/output (done, but not enough): • Must be able to test SVT in place, with proper timing and data flow, even without SVX/COT/L2/beam • Not only hw test, also operating/monitoring software • More functions and flexibilityfor board/system testing added on the road • Plan for long, demanding, integration/commissioning • Should have invested much more in software much sooner • More features could be implemented • More people easily trained (less expert demand) • When come to integrating electronics: be creative. Any way to bypass/emulate other system/boards must be pursue and strongly looked for. be creative…

  8. First Phase: Organization • CDF has early established shifts/DAQ always running once IN, a system must work and be correctly monitored and checked • Sometimes testing activities not so easy. • The payoff is a system kept working, running and steady growing Very important: Fight hard the Entropy • Train “Shift Professionals”: ACEs. Stay in shift for3 monthes- overlap 1 monthes. CDF still works this way.

  9. Begin Commissioning with Beam • Oct 2000 Commissioning Run • Si “Barrel 4” only • Many other systems partial • COT recently on-line (seen 1st cosmics few days before roll-in) • Nov. 2000-March 2001 • Complete the detector • Continued integration work • Daily cosmic running • March 2001-February 2002 • Commission for physics data Commiss.Run had some of everything: enoughto shake down much of systems

  10. The Commissioning Run Crucial event of CDF commissioning Date 5/9 18/9 Ottobre 2000 Week -2 -1 0 1 2 3 4 5 6 Period Roll-in A B C Lum. 10^29 10^30 Bunches proton 1 x 8 1 x 8 36 x 8 36 x 36 • Period A : Proton only beam (1.5 wks) • Period B : Observe first collision (1 wk) • Period C : Subsystem commissioning (3.5 wks) Y.K. Kim/Sep.2000

  11. Commissioning Run Plan • Period C (1x8, 36x8, 36x36 bunches) • Understand operation of COT with colliding beam • Stability of the chamber with a large amount of ionization • Determine hit occupancies / efficiencies per superlayer • Begin to understand tracking issues / t0, drift velocity • Synchronous noise from Silicon readout ? • Understand operation of Si Barrel-4, new endplugs. • Commission calorimetry and muon systems. • Commission DAQ system (Hardware Event Builder, L3, Data Logger …) • Establish operation of L1 Trigger system functionality • Calorimeter & muon stubs triggers • Tracking slice COT – XFT – XTRP to Muon / Calorimeter • Capture data in L2 processors, simple tagging/prescaling • Read-in L1 and XFT info, Cluster and ISO cluster operation • SVT for instrumented region • Take a few hundred k good events for the COT for the post-run Y.K. Kim/Sep.2000

  12. The First Collisions!! L1 Beam profile Good Tracks L2 Non dimentichiamo!! A volte pochi giorni di collisioni produconorisultati straordinari Impulso alla collaborazione

  13. From the Commissioning Run • some data K short peak SET=500 GeV di-jets Cambiare plots • a lot of work accomplished • …and a better understood list of the work to be done Still 4 monthes to go: Begin Run II March 01

  14. Downtime logger • Detailed accounting of the reason CDF is not taking data (loosing luminosity) • Very powerful tool to immediately identify what systems are causing inefficiency (not always so obvious) • Used by operation/commissioning manager to prioritize and decide work schedules • Identify weakness/limitations of systems

  15. Silicon Commissioning • Only prototype Si installed for commissioning run • Allowed Si DAQ commissioning. • Si readout did not cause noise problems elsewhere. • BUT most of Silicon commissioning still to be done! • Si was installed in Jan 2001 with just 2 months to start of Run II (722K channels) - shifts 24 hours a day, 7 days a week • But Installation completed in May 2001(beam in Mar 01) • Access to collision hall restricted before connection complete:schedule complicated

  16. E’ iniziato il run II..Commissioning with Data • Early J/ydata (few pb-1) • basic momentum scale for tracking • measure muon chamber efficiencies • SVX vertex resolution • Photon conversions used to • understand the radial material • distribution August 2001 1pb-1

  17. Tracking Chamber Alignment • Cosmic ray based alignment: Cell tilts/shifts • Includes corrections for electrostatics and gravity Impact parameter vs. phi

  18. First unexpected problems • Early TeV beam had high losses • Silicon frequently off for protection • Muon chamber currents very high (installed shielding) • Power supply failures with beam • Transistor deaths due to “single event burnout” • Reduced bias/more resistant transistors/shielding • ISL cooling lines blocked • Initially could not operate detector • Blockage due to epoxy in 90o bends • Cleared using Yag LASER + prism Recovered June 02

  19. Beginning of Physics Run • February 2002 is the START OF PHYSICS date • Still 2002 was a painful year: still a lot to learn and improve • Unexpected problem in detectors • Beam incidents • Still in 2003: The first run II paper published D,Ds M = 99.410.380.21 MeV PDG: 99.20.5 MeV

  20. Silicon Jumper failure Aging COT A small but steadily growing number of CDF silicon detector modules were dying. Breakage of a wirebond CDF central tracking chamber: Aging  resolved • Some broke during a trigger test at ~20 kHz • Oriented orthogonal to 1.4 T B field • Fundamental frequency for 2 mm Al bond ~20 kHz Resonant oscillation from Lorentz forces during special trigger conditions! • Reduced current through jumper • Eliminated guilty trigger test mode • Lost some sensors (z-sidemainly) Resolved!

  21. Beam Incidents & CDF Safety • Based on Run I experience: • Procedures for store fill and scrape, and store end • hardware and procedures for minimizing radiation dose to silicon detector – intended to lengthen life of detector • Measure losses from p and pbar bunches NOT ENOUGH !! Not well protected against beam incidents. A run II news LHC beam power = 250 x Tevatron!

  22. Beam related Problems • Very Serious • Fast beam loss (risk was known, but..) – Damage Silicon • Damage to silicon from low doses (100’s of rads) at high rate (100 nsec) [particular failure mode not reproduced in tests] • Serious • Damage to various electronics in collision hall due to SEB (single event burnout) or similar single events  abnormally high losses • One bad example: beampipe misaligned during access  proton halo scraped  Lost ~12 crate power supplies over about an hour Actions: • Added shielding around low-b quads • Reduced bias voltage in VME power supplies / modify power supplies • Annoying • Example: Beam induced background in missing ET trigger  halo scraping upstream of CDF

  23. Abort Kickers • Kickers are very fast  Danger of fast beam loss: • Kicker prefire • Actions: • Reduce prefire rate (kicker conditioning) • Add collimator for almost perfect shadowing  needed full lattice+MARS simulation A11 collimator Already in place a “task force” in AD ~ end 2004 A0 proton abort kickers Add .5 m Collimator at A48 to shield against prefires

  24. The Abort Gap • Kickers fire correctly, but beam in the abort gap • Discovered beam in the abort gap when quenched and suffered silicon damage on abort! • Monitor the gap • CDF added monitoring of local losses in abort gap  useful diagnostic for accelerator – adopted jointly, in TevMon • Accelerator added better instrumentation– adopted jointly • Failure of specific Accelerator systems can spill beam into the abort gap • Early incident: RF problem drove significant beam into abort gap 1% of silicon detector lost (unable to talk to chips) • Added beam abort interlock, monitored in TevMon • “Tevatron Electron Lens” used to clean the abort gap, monitored in TevMon

  25. Important Lesson • monitor state of potentially dangerous systems in the accelerator - RF system, electron lens etc • … Learned by analyzing each serious machine accident • monitor the accelerator as if it were a detector system

  26. Important Lesson • Experiment must worry about its own safety – and work closely with Accelerator Division to ensure it • CDF enjoyed good communications with AD Operations Manager and Tevatron experts – this is important • Joint CDF+AD instrumentation for monitoring • Determine the cause of every serious beam incident and take corrective action (bullet may not miss you next time) • Corrective actions may require significant work from the Accelerator Division ’’(quoting J. Spalding) LHC LHC, ATLAS, CMS failure modes will not be the same. But potentially all loss issues will be more severe Importance: monitoring, diagnostic tools, collimater, shielding, communication between machine and exp. teams

  27. A Physics Heavena Very Complex Trigger! ~ 200 trigger path • 185 a L3 - 131 a L2 – 56 a L1 • Defining a working and suitable trigger table one of the more complex task of commissioning • CDF began planning long in advance of run II: • - a group devoted to organize, define, estimate trigger rate based on data on run I and detailed simulation • - for every trigger proposed: a long list of works to be done before trigger approval • this is true now as well -> plan for ~1 year work • Despite all this work in CDF: a continuous fight • never ending upgrades/commissioning Time

  28. Trigger & L • Principle:physics process trigger cross section, σ = B (const) Reality: a trigger cross section, σ ~ A/L+ B + CL+ DL2 + … • CDF has worked a lot on trigger rates -> still failed to correctly predict how they grow with L. It is a difficult task! A good trigger system allows one to easily adopt (CDF trigger has lot of features: L enable, Dyn.Presc. etc) Still “hard choices” could be needed (drop some physics) Still one of the top CDF headachestoday MET25+2JET

  29. Trigger Summary • A flexible trigger table handling is essential to cope with the continuous changes and increasing performance demand • Work to insert relevant physics channels in the trigger table since the beginning. Late insertion can turned to be painful • A very good trigger simulation is an essential tool: be sure all you need is insince early days

  30. …and now: Where can I run my jobs? • While in the commiss. period (2001) it became clear the Computing model for data analysis was not good anymore.Needed CPU x10 + painful tape access -> Old system trashed • 2002 a new model (CAF). In ~ 6 monthes a small CAF was working -> In 1 year users enjoyed our beloved CAF First impact with data (and users) could destroy all your planning -> Don’t panic: there is some time -> A complete revolution is possible and sometimes desirable Are CPU and human energy waisted? Yes - CDF did not provide: • simple tools to manage the analysis of large datasets • strong set of easily available debugging and code analysis tools • Motivation/organizations to more centralized processing • When conference pressure-> too late. Users find their way…

  31. …Non manca molto al passaggio del testimone  It is time to begin running together! Still CDF has his best years of physics production ahead. Should get 4 X Lint. CDF work for LHC in many areas (backgrounds, MC tuning, QCD, W&top mass etc): don’t overlook the possibility to learn something today of your favorite physics channel. Put your request on the table now: but this does not mean you will get it (manpower)…… The best attitude: do it yourself! Why not begin to commission LHCusing CDF ?? Join CDF as a Visitor: you could play with your favorite CDF datawith no duties

  32. ..c’e’ il rischio (o la speranza!) che qualcuno esageri un po’ TEVATRON LHC Don’t tell me you discovered Higgs!! Cartoon: courtesy of Young Kee Kim Many thanks to: Y.K.Kim, T. Liss, T.Liu, J. Spalding and many others

  33. BACKUP

  34. Beam Loss Monitor snapshot for a messy abort D0 low b quads CDF note: CDF shields D0 abort dump

  35. Run II

  36. Tevatron Run-II • ICHEP-04 Results : 200 pb-1 • ICHEP-06 Results : 1000 pb-1 (per experiment) Delivered Luminosity pb-1 200220032004 2005 2006 • Data set has doubled every year

  37. Triggering in Run 2 Central Tracker (Pt,f) EM + HAD/EM + Track EM+HAD (Jet) Muon + Track Missing ET, S ET Si Secondary vertex EM shower max, ISO Jet Clustering Multi object triggers Farm of ~200 PC’s running fast versions of Offline Code  more sophisticated selections 45 kHz 300Hz 60 Hz ~20MB/s

  38. Commissioning with Data • Additional J/y data used to understand material • And alignment M(J/y) vs. Pt : Additional 0.455 g/cm2 Corrected for nominal material in simulation No corrections Residuals in 5 SVXII layers

  39. Abort Gap Tevatron has 3x12 bunch trains and 3 abort gaps (2 ms long)

  40. Average Luminosity 0.9 fb-1 1E32cm-2s-1 By fiscal year

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