Commissioning TileCal with Cosmic Ray Muons J. Pilcher University of Chicago

6/24/03J. Pilcher2 TileCal Assembly Schedule Surface preassembly of barrel  Complete preassembly December ’03  Start disassembly late February ’04  ~2 months possible for commissioning studies  Cs studies over full height of barrel  Cosmic ray muons through full readout system Underground assembly of barrel  Begin 11 May ’04  Module assembly complete 10 Sept. ’04  Services complete 26 Nov. ’04  Tests and commissioning 29 Nov. ’ Dec. ’04  Short time (4 weeks)  Unpopular time for working  We must be efficient and well prepared

6/24/03J. Pilcher3 Commissioning Preassembly Goals  System tests with more modules  Largest system run to date is 6 superdrawers –In test beam  Full barrel contains 128 superdrawers  Intermediate step is essential  System tests with hardware not yet used  LV power supply sets in fingers  Bulk LV power source 80m away  LVL1 trigger hardware interfacing to TileCal –Patch panels to remap tower and muon signals –Receiver boards  Hardware RODs

6/24/03J. Pilcher4 Commissioning in Pit Check that all systems are alive in Dec. ’04  Cs and CIS runs  Thorough check-out with “physics” signals will take longer Attractive to run system on cosmics periodically from Dec. ’04 - Dec. ’06  Monitor stability  Get all bugs ironed out  Provide trigger to other parts of ATLAS  Likely very little access to pit during this time  Most work in USA15

6/24/03J. Pilcher5 Estimate Trigger Rates Consider rate in back-to-back trigger towers ( equipped modules)

6/24/03J. Pilcher6 Estimate Trigger Rates These triggers are the most useful  Muon fully traverses single towers  Could also select these muons with bottom section of cal. and scintillator in “beam” region Rate is lower than trigger using larger towers (eg. 0.4 x 0.4)  Return to this case later Do simple calculation with Excel

6/24/03J. Pilcher7 Cosmic Ray Flux Use numbers from Particle Data Group  Tabulate in Excel

6/24/03J. Pilcher8 Cosmic Ray Flux Integrate over muon energy above a threshold  Must impose range cut-off, depending on  (or  )  Set up table for linear interpolation  Gives muons / sec / m**2 / steradian

6/24/03J. Pilcher9 Cosmic Ray Flux Range information  Use PDG, Sec. 26, Ref. 1 for range-energy & dE/dx  Article by D.E. Groom et al., Nucl. Data Tables 78, for muons in iron  Set up table for linear interpolation  Use module geometry from CDD drawings  Solid steel at inner and outer radii (including girder, etc.)  Steel and scintillator mixture between

6/24/03J. Pilcher10 Rate Calculation Consider back-to-back cells  Area from plane mid-way through A-cell on bottom  Solid angle from corresponding plane on top  Scale rate by cos 2  (zenith angle)  Integrate over wedges in 

6/24/03J. Pilcher11 Rate Variation with  and  Plot fraction of total rate versus  and   Easy to scale rate to smaller configurations

6/24/03J. Pilcher12 Rate Estimate in UX15 Pit PX16 (10 m Inner Dia.) PX14 (14 m Inner Dia.)

6/24/03J. Pilcher13 Rate Estimate in UX15 Pit Overburden corresponds to 55 m of rock with density 2.4 gm/cm**3 Range cut-off now 34 GeV instead of 4 GeV  Based on CERN Yellow Report  SPS study of range-energy and dE/dx of high energy muons Expected rate reduction is factor of ~22  Zenith angle dependence of overburden not included  Would give ~10% reduction  Vertical access shafts not included  Would increase rates for certain  and  Expected rate ~90/hr  Rob McPherson has been asked for a more detailed GEANT-based estimate

6/24/03J. Pilcher14 Rate with Alternative Trigger Consider trigger on towers of (0.4 x 0.4)  Same area as before but solid angle increased by 16  Rate increased by ~16  32K events/hr on surface (was 1.9K/hr)  1.5K events/hr in pit (was 0.09K/hr)  Energy spread over several towers  Trigger less clean  Events less useful for calorimeter diagnostics  Much less trigger hardware needed  Could filter events at LVL2

6/24/03J. Pilcher15 Comments on Rates There is a very useful trigger rate both on the surface and in the pit Actual rate on surface next winter will depend on how much electronics is available

6/24/03J. Pilcher16 Hardware Needed Electronics drawers (64) - probably OK LV power in fingers Bulk LV power (200V for USA15) Cabling and fibers TTC hardware LVL1 trigger interface hardware  Patch panels to separate tower and muon signals  Receiver boards (64 towers each)  Trigger logic for cosmic ray running LVL2 hardware  ROD modules  ROD crate and controller  Output hardware from ROD crate (Ethernet?)

6/24/03J. Pilcher17 LV System 200V Power Monitoring Control LV supplies to Patch Panel Set of 8 DC to DC converters With monitoring and control in each finger

6/24/03J. Pilcher18 LV System Need full scale prototype for 2 fingers with 200V bulk supply, cables, splitter boxes  This summer? Need preproduction units  Use in preassembly commissioning next winter  64 of 256 fingers?  32 of 256?  looks reasonable  Feasibility????

6/24/03J. Pilcher19 LVL1 Interface Hardware Cable from barrel drawer delivers 9 tower signals and 7 muon signals  Splitter box needed to collect tower and muon signals on separate cables  Group tower signals as needed for LVL1 receiver boards  Whose responsibility??? Drawing shows required organization for drawers

6/24/03J. Pilcher20 LVL1 Interface Hardware Receiver boards produced a single-ended, conditioned, analog signal for each tower  Will go to flash ADC boards in ATLAS  Could be used for cosmic trigger instead  Trigger on towers of 0.4 x 0.4 for 8+8 modules requires the following –add analog signals in groups of 16 towers (0.1x0.1 to 0.4x0.4) –Require energy threshold on sum (discriminate) –Take 8 2-fold coincidences between back-to-back towers –Take OR of the 8 coincidence outputs

6/24/03J. Pilcher21 LVL2 Hardware Data from drawer goes to ROD modules  1 module handles 8 drawers  8+8 modules  32 drawers or 4 RODs  Needs ROD crate and ROD Crate Controller  Might log data from RCC over Ethernet –Done for other systems in test beam ROD schedule?  2 prototype modules planned for September  Can we get 4?  Production not until next spring

6/24/03J. Pilcher22 Conclusions Commissioning with muons is attractive and necessary  The trigger rates look fine Try this week to agree on target configuration for next winter  Confirm responsibilities and explore timetable with TDAQ groups Over next few weeks make more precise list of items needed and identify items requiring more help People willing to help might meet in July to agree on division of tasks (phone + video + face-to- face)