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

Early Commissioning of ATLAS

First North American ATLAS Physics Workshop

Tucson

J. PilcherUniversity of Chicago

20-Dec-2004 J. Pilcher 2

Early Commissioning of ATLAS

10 Dec 04


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


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, ) Z → l +l − W → jj


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:

http://agenda.cern.ch/fullAgenda.php?ida=a041267

Overview week at Freiburg: commissioning session http://agenda.cern.ch/fullAgenda.php?ida=a041780#s0

Overview week at Prague: commissioning session http://agenda.cern.ch/fullAgenda.php?ida=a03190#s2

This talk draws on the work of many people R. Teuscher, R. McPherson, J. Huston, …


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


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, BCID @ 100 kHz L1A, CIS, readout noise, …

Charge InjectionPulses OK

Noise Test OK

RM

S (

AD

C c

ount

s)


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


Charge Injection Calibration of TileCal

Pulse individual channels over full dynamic range establish gain, linearity, stability

Uncorrected channel-to-channel uniformityRMS ~ 1.3 counts/pC (1.6%)

Gain variation over 4 months of CTBRMS ~ 0.2%


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%


Cosmic Ray Commissioning

Full G3 simulation done by Rob McPherson and Pavel Nevski


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


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)


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)


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


-distribution of muons -distribution of muons passing Tilecal triggerpassing Tilecal trigger

-0.1-0.2-0.3-0.4-0.5

PX14 PX16

D = 18 m D = 12.6 m

Effect of PX14 shaft isclearly seen

TileCal Cosmic-Muon Trigger


Typical Events


Typical Events (2/2)

Example of muon scattering in detector


Muons in LAr BarrelDue to Accordion geometry, muons are reconstructed in middle compartmentby 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


Muons in LAr Using TileCal Trigger TileCal Trigger tower size (0.10.1) corresponds to 44 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)

CellEnergy

Studies of rate in LAr using TileCal cosmic trigger (back-to back towers) by Philippe Schwemling and Emmanuel Monnier. Est. ~ 6 months run


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)

MuonsE~300 MeVt ~ 6 ns

Test-beam data

1% precision measured with ~1000 with ~ 5000 : 0.5 % precision (~ 100 /cell integrated over )


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


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

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

0 20 40 60 80 100 120

Threshold (mV)

Trigger Efficiency

Test by injecting muon signal into trigger tower

Vary tower threshold and check efficiency


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


First commissioning with single beam

Beam halo muons Generated by machine group Simulated in ATLAS

Beam gas events

Beam-gasBeam-halo

Scoring plane


A “typical” beam-gas event

Beam-gas collisions are essentially boosted minimum-bias events low-pT particles

Rate : ~ 2500 interactions/m/s


Beam-gas Rates & Properties

Vertex ZVertex Z Rate (Hz)Rate (Hz) TotalTotal (2 months, (2 months, =30%)=30%)

23 m23 m 1.2x101.2x1055 2.1x1011

3 m 1.6x104 2.4x1010

20 cm 1.1x103 1.6x109

pT > 1 GeV 1.0x103 1.5x109 inside 3m pT > 1 GeV 0.3x103 5.6x108 inside 3m

ET spectrum in ECAL E spectrum in FCAL

ET charged particles


Beam Halo Muons

Total rate 105 kHz E > 10 GeV 16 kHzE > 100 GeV 1 kHzE > 1 TeV 10 Hz

L=1034

Muons at cavern entranceMuons at cavern entrance

Especially useful for endcaps and ID disks and wheels


Beam-Halo Rates

Estimate rates for 200 times less current than design Totals in table for 2 month run at 30% efficiency

Detector Rate (B-field off )

Total (B-field off)

Rate (B-field on)

Total (B-field on)

MDT barrel 15 Hz 2.5x107 72 Hz 1.5x108

MDT end-cap

145 Hz 2.5x108 135 Hz 2.5x108

Pixel/SCT 1.8/17 Hz 3x106 / 3x107 2/19 Hz 3x106 / 3x107

EM E > 5 GeV

2 Hz 3.5x106 1 Hz 1.7x106

Tile/HEC E > 20 GeV

1.7/1.2 Hz 2.9/2.1x106 1.6/0.9 Hz 2.8/1.6x106


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.


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

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

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