Early Commissioning of ATLAS First North American ATLAS Physics Workshop Tucson J. Pilcher University of Chicago

20-Dec-2004J. Pilcher2 Early Commissioning of ATLAS 10 Dec 04

20-Dec-2004J. Pilcher3 Commissioning Goals Establish operation of full systems  Readout  Calibration systems  Low Voltage, High Voltage  Control and Monitoring  Cryogenics, Gas, Cooling Establish initial calibrations  Mev/ADC count  Alignment and timing  Chamber or sensors within a detector system  Relative alignment and timing of different detector systems Demonstrate performance levels  Noise levels  Physics signals

20-Dec-2004J. Pilcher4 Commissioning Stages Calibration systems only Cosmic ray muons  MIP signals and inelastic interactions  Stand-alone detector systems (2005-6)  Full ATLAS detector (2007) Initial beam operation  Single beam operation  Beam-gas interactions  Beam halo muons  Beam-beam operation  Minimum bias interactions Early beam-beam collisions  Use physics signals (,  -j, Z-j, j-j, )

20-Dec-2004J. Pilcher5 This talk  Concentrate on first three stages  Other talks on commissioning with beam-beam physics signals  Special emphasis on calorimeter systems More details at:  Tatra Workshop:   Overview week at Freiburg: commissioning session   Overview week at Prague: commissioning session  This talk draws on the work of many people  R. Teuscher, R. McPherson, J. Huston, …

20-Dec-2004J. Pilcher6 Preliminary commissioning already being done  Combined test beam in 2004  Tilecal operation on cosmic muons in Bldg. 185  LAr operation on cosmic muons in Bldg. 180  Muon chamber operation with cosmics  TileCal barrel on HF truck in UX15 Commissioning is iterative with larger scale integration at each step

20-Dec-2004J. Pilcher7 Now: TileCal Commissioning on HF Truck in UX15 Photo from September 28, 2004 Record data from UX15 testing TTC, CANbus, HV, laser fibres via LED, 100 kHz L1A, CIS, readout noise, … Charge Injection Pulses OK Noise Test OK RMS (ADC counts)

20-Dec-2004J. Pilcher8 Barrel calorimeters move to z=0 August 2005 when BT is assembled  Detectors fully assembled and equipped with on-detector electronics  Connect to services  Stand-alone commissioning with calibration systems  Eg. for TileCal (1/2 the system) –Charge injection to all readout channels (4K in barrel) –Cesium source activates tiles and fibers (220K in barrel) –Laser system activates each PMT (4K in barrel)  First large-scale detailed commissioning

20-Dec-2004J. Pilcher9 Charge Injection Calibration of TileCal Pulse individual channels over full dynamic range  establish gain, linearity, stability Uncorrected channel-to-channel uniformity RMS ~ 1.3 counts/pC (1.6%) Gain variation over 4 months of CTB RMS ~ 0.2%

20-Dec-2004J. Pilcher10 Cs Calibration of TileCal Cs-137 source illuminates individual tiles  Stainless tubes pass through all tiles in the system  Source capsule driven through tubes hydraulically  Single tile response measured at 2% level  Cell response measured at 0.3% level  Week-to-week variations in cell response ~ 0.5%

20-Dec-2004J. Pilcher11 Cosmic Ray Commissioning Full G3 simulation done by Rob McPherson and Pavel Nevski

20-Dec-2004J. Pilcher12 Cosmic Ray Commissioning Rates are substantial  2.3 KHz for a hit anywhere in detector  0.5 Hz for |Z| < 60 cm, R < 20 cm Natural to trigger with muon system RPCs + … Global ATLAS cosmic muon run planned for 40 days in April 2007 before LHC starts Attractive to run barrel calorimeters on cosmics from late 2005  Before RPCs available  Evaluated trigger using TileCal  back-to-back trigger towers

20-Dec-2004J. Pilcher13 TileCal Response to Muons Test beam data for 180 GeV muons at  =0.05 Energy depends on path length through calorimeter 1K muons in a tower gives response to 1% S/N ~ 40 Tower Energy (pC) (~1.1 pC/GeV)

20-Dec-2004J. Pilcher14 TileCal Cosmic-Muon Trigger Consider back-to-back TileCal towers   x  =0.1 x 0.1, full calorimeter depth  Especially useful because tracks pass close to interaction point  Analyze McPherson/Nevski simulation for rate and event properties  S. Zenz (Chicago undergraduate)

20-Dec-2004J. Pilcher15 TileCal Cosmic-Muon Trigger Require 2 back-to-back towers with E > 1.5 GeV  Lower peak corresponds to additional towers struck (corners clipped) Rate is ~ 130  /hr for 16 top + 16 bottom modules in coincidence ~ 100K / month

20-Dec-2004J. Pilcher16  -distribution of muons passing Tilecal trigger PX14PX16 D = 18 m D = 12.6 m Effect of PX14 shaft is clearly seen TileCal Cosmic-Muon Trigger

20-Dec-2004J. Pilcher17 Typical Events

20-Dec-2004J. Pilcher18 Typical Events (2/2) Example of muon scattering in detector

20-Dec-2004J. Pilcher19 Muons in LAr Barrel Due to Accordion geometry, muons are reconstructed in middle compartment by summing two cells in . S(  )/N  7 Barrel middle compartment Test-beam data With 100 events muon signal in LAr can be measured with ~ 3% precision For first shake-down Could use cosmic ray muons to measure first LAr physics pulse shapes and compare to calibration pulses. Useful to reconstruct combined muons in LAr + TileCal to match EM energy scale and timing. Note : S/N ratio too small in strip and back compartments

20-Dec-2004J. Pilcher20 Muons in LAr Using TileCal Trigger TileCal Trigger tower size (0.1  0.1) corresponds to 4  4 LAr middle cells Resulting maximum non-projectivity :  3º, muons can cross at most 2 cells in  and in   non-projectivity probably not a problem, due to natural sharing between  cells (two cells are summed) Cell Energy  Studies of rate in LAr using TileCal cosmic trigger (back-to back towers) by Philippe Schwemling and Emmanuel Monnier. Est. ~ 6 months run

20-Dec-2004J. Pilcher21 With ~ 100 muons/cell in middle compartment Check calorimeter timing to < 1 ns  input to optimal filtering in ROD Check calorimeter position in  /  wrt other sub-detectors to < 1 mm  t = 1.62 ns/E (GeV) + 19 ps (from calibration) Muons E~300 MeV  t ~ 6 ns Test-beam data 1% precision measured with ~1000   with ~ 5000  : 0.5 % precision (~ 100  /cell integrated over  )

20-Dec-2004J. Pilcher22 Hardware Needed for TileCal Cosmic Trigger Electronics drawers in barrel (128) LV power (in TileCal fingers)  Bulk LV power (200V for USA15) Cabling and fibers TTC hardware  Standalone clock LVL1 trigger interface hardware  Patch panels to separate tower and muon signals  Receiver boards (64 towers each)  Initially use custom trigger logic for cosmic ray running ROD/LVL2 hardware  ROD modules, ROD crate and controller (ROD crate DAQ)  Output hardware from ROD crate to PC via Ethernet  Later use ROBIN/ROS

20-Dec-2004J. Pilcher23 TileCal Muon Trigger Logic LVL1 trigger not designed to run on back-to-back muons  Adapting it would be a diversion  Also scheduled to arrive late compared to initial stand-alone calorimeter operation Build some simple coincidence logic Test by injecting muon signal into trigger tower  Vary tower threshold and check efficiency

20-Dec-2004J. Pilcher24 Time Table for Cosmic Ray Commissioning TileCal barrel complete Mar-06 (following checkout)  Stand alone operation begins LAr barrel complete Aug-06 (following checkout)  Stand alone operation begins Global commissioning Dec-06 through Feb-07 ATLAS cosmic run  Mar-07 through Apr-07 ATLAS ready for beam 4/27/07

20-Dec-2004J. Pilcher25 First commissioning with single beam Beam halo muons  Generated by machine group  Simulated in ATLAS Beam gas events Beam-gas Beam-halo Scoring plane

20-Dec-2004J. Pilcher26 A “typical” beam-gas event Beam-gas collisions are essentially boosted minimum-bias events  low-p T particles Rate : ~ 2500 interactions/m/s

20-Dec-2004J. Pilcher27 Beam-gas Rates & Properties Vertex Z Rate (Hz) Total Vertex Z Rate (Hz) Total (2 months,  =30%) (2 months,  =30%)  23 m 1.2x10 5  23 m 1.2x x10 11  3 m 1.6x x10 10  20 cm 1.1x x10 9   p T > 1 GeV 1.0x x10 9 inside  3m  p T > 1 GeV 0.3x x10 8 inside  3m E T spectrum in ECAL E spectrum in FCAL E T charged particles

20-Dec-2004J. Pilcher28 Beam Halo Muons Total  rate 105 kHz E  > 10 GeV 16 kHz E  > 100 GeV 1 kHz E  > 1 TeV 10 Hz L=10 34 Muons at cavern entrance Especially useful for endcaps and ID disks and wheels

20-Dec-2004J. Pilcher29 Beam-Halo Rates Estimate rates for 200 times less current than design  Totals in table for 2 month run at 30% efficiency DetectorRate (B-field off ) Total (B-field off) Rate (B-field on) Total (B-field on) MDT barrel15 Hz2.5x Hz1.5x10 8 MDT end- cap 145 Hz2.5x Hz2.5x10 8 Pixel/SCT1.8/17 Hz 3x10 6 / 3x10 7 2/19 Hz 3x10 6 / 3x10 7 EM E > 5 GeV 2 Hz3.5x Hz1.7x10 6 Tile/HEC E > 20 GeV 1.7/1.2 Hz2.9/2.1x /0.9 Hz2.8/1.6x10 6

20-Dec-2004J. Pilcher30 Triggering on Beam Halo and Beam-Gas events Minimum-bias scintillators being added in front of LAr end caps  z ~ ± 3.5 m  14 cm < R < ~ 100 cm  ~1.9 <  < ~3.9  8 channels in , 2 channels in   Readout via TileCal electronics drawer Joey Huston is project leader on this.

20-Dec-2004J. Pilcher31 Conclusions Good prospects for progressive commissioning process  Stand alone detector systems with calibration systems and cosmic muons  Global detector with cosmic muons  Beam halo muons and beam-gas events in early 2007  Minimum bias beam-beam interactions by mid 2007 Fully simulated samples of cosmic muons, beam-halo muons and beam gas events exist  R. McPherson et al. Final commissioning phase will be with physics signals  Essential for final tune-up  Essential for showing we understand the detector behavior