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The Muon Spectrometer Commissioning and Upgrades. Joao Guimaraes da Costa for the ATLAS Harvard Group DOE Site Visit - 2009. Harvard People Working in the Muon System. (Dark Red: People working at CERN). (List incomplete as several people involved in the construction have left). Faculty :

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The muon spectrometer commissioning and upgrades l.jpg

The Muon SpectrometerCommissioning and Upgrades

Joao Guimaraes da Costa

for the ATLAS Harvard Group

DOE Site Visit - 2009

Harvard people working in the muon system l.jpg
Harvard People Working in the Muon System

(Dark Red: People working at CERN)

(List incomplete as several people involved in the construction have left)

  • Faculty:

    • George Brandenburg (retired)

    • Melissa Franklin

    • Joao Guimaraes da Costa

    • John Huth

    • Masahiro Morii

  • Postdocs:

    • Alberto Belloni

    • Kevin Black

    • Shulamit Moed

  • Technical support

    • Electronics shop

      • Sarah Harder (retired)

      • John Oliver, Meghan Kundoor

    • Mechanical shop

      • Steve Sansone

  • Graduate students:

    • Laura Jeanty

    • Michael Kagan

    • Lashkar Kashif

    • Verena Martinez Outschoorn

    • Srivas Prasad

    • Emily Thompson (Univ. of Mass, Amherst)

    • Giovanni Zevi della Porta

  • Undergraduate students

    • Michael Fountaine

    • Jack Kearney

    • Tomo Lazovich

    • Curt Nehrkorn

LPPC Harvard ATLAS Group

The atlas muon system l.jpg
The ATLAS Muon System

Endcap (BW+SW+EO+EE)

Outer Wheel - EO


Big Wheel


Barrel (MDT+RPC)


(MDT: 2 x 96)

(2 x 80)


(2 x 31)

Chamber construction: BW+ SW (80)

Integration: BW+SW+EO+BEE+EE

Electronics and DAQ: Full MDT

Commissioning Analysis: Full MDT

(2 x 40)

Small Wheel




(2 x 16)

Monitored drift tube mdt chambers l.jpg
Monitored Drift Tube (MDT) Chambers

Single tube

resolution: ~ 80 μm

Al tube

Ar/C02 (93:7) @ 3 bar

Gain: 2 x 104; HV= 3080V

Max drift time = ~ 700 ns


LPPC Harvard ATLAS Group

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On-Chamber Readout Board

ASD/TDC Mezzanine board designed, produced and tested at Harvard (collaboration with BU)

George Brandenburg, John Huth, Sarah Harder, Joao Guimaraes, John Oliver, Werner Riegler

18k Mezz boards (full MDT system)

67k ASD chips

  • Tests/repairs

    • LPPC electronics shop

      • Sarah Harder

    • Giovanni Zevi della Porta


LPPC Harvard ATLAS Group

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Integration, Commissioning and Data Preparation

Mostly in prior






Electronics (Mezz, CSM)



Alignment studies


Firmware upgrades

Magnetic Field Studies

Offline Monitoring

Power supplies


Online Monitoring

Coordination of Software Releases

Readout Drivers (MRODs)

Cosmic Ray Analysis


Control Room











Cosmic Ray


LPPC Harvard ATLAS Group

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Major Installation and Maintenance Operations this Year


Collaboration with UM, BU, Barrel Colleagues and Technical Division

  • Maintenance of BWs

    • Installation of radiation hard optical readout fibers

      • Side C: November 2008

      • Side A: May 2009

    • Fixed minor gas and electrical problems in a few chambers

  • Maintenance of SWs

    • Fixed minor electrical and gas problems

  • Integration of all BEE chambers

    • Integration in February 2009

  • Installation of EE chambers

    • Integration in DAQ on-going

  • Replaced readout boards in all barrel MDT CSMs

    • Operation at 50 MHz

LPPC Harvard ATLAS Group

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Status of the MDT Chambers

Very low percentage of failed components

Readout channels: ~0.4%

2.5% before shutdown

1098 chambers will be operative by start of collision data

Including 8 EE chambers being integrated now

Missing 52 EE chambers


LPPC Harvard ATLAS Group

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DAQ activity

Harvard group is playing a major role in Muon DAQ operations

Alberto Belloni is the Deputy Muon DAQ Coordinator

Only MDT DAQ expert resident at CERN

Integrated all endcap chambers

Including MROD optical fiber installation

Responsible for Run Control configuration

Organized and led commissioning of chambers

Prepare and take test runs

For instance, noise runs BEE, EO

Check readout/HV mappings

Track chamber problems

Identify and assign repair activities

Close contact with Detector Control System (DCS) support group

Experience in detector installation and commissioning

Support of power system

Students Laura and Giovanni and new postdoc joining this year


Run Control

LPPC Harvard ATLAS Group

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More DAQ contributions

Improvements of DAQ system

Provided numerous scripts for most common expert tasks

Developed the MDT Control Panel

Graphical interface for chamber RO configuration

Giovanni and Tomo

Stopless recovery for MDT chambers

High rate operation at 75kHz

Reduction of transition times during start/end of run

LPPC Harvard ATLAS Group

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Operations in the Control Room

Constant presence in the control room since Feb. 2007

DAQ Expert: Alberto Belloni (on-call expert), Verena Martinez, Srivas Prasad

Monitoring Expert: Shulamit Moed, Michael Kagan

MDT Endcap Coordination: Joao Guimaraes


Muon DAQ: Verena, Srivas, Giovanni, Kevin, Lashkar, Laura, Michael

Muon Data Quality Assessment: Michael Kagan

Run Control: Verena Martinez

Shift Leader: Joao Guimaraes, Alberto Belloni

Defining procedures, improving documentation

Many contributions in DAQ

Manuals for shift crew

Twiki pages for shift crew

Training MDT shifters during monthly training sessions (Alberto)

Muon online monitoring (DQMF)

Manuals for shift crew

Event display configuration

Atlas Control Room

LPPC Harvard ATLAS Group

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Pulser runs

New testing and calibration tool

Calibration capacitor on mezzanine boards

Controlled test of each readout channel

Framework for automatic startup of MDT pulser runs and analysis of results in preparation

Initial tests very successful

In single tube, same pulse

at same time (TDC)

Pulses in half of the tubes

Cross-check of mapping

LPPC Harvard ATLAS Group

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Magnetic Field Studies

More realistic model of the coils

Inter-coil connections contribute with ~40-50 gauss at sensor positions

Being added to field simulation

  • Understanding of magnetic field is one of the major challenges for muon reconstruction with real data

    • Magnetic field is highly inhomogeneous, specially in the transition region between the barrel and endcap

    • Correlation between simulations from currents in the coils and magnetic field reconstruction from ~1730 Hall probes

  • Morii (together with Nehrkorn and Fountain) is continuing these studies

LPPC Harvard ATLAS Group

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Reconstruction Software

  • Harvard group has made significant contributions to the muon reconstruction software for several years

    • Muon Track Reconstruction Development (MOORE)

    • New Segment Fitting Code for Cosmics (see later slides)

  • Focus on validation and commissioning this year

  • Muon Spectrometer/Combined Muon Performance Release Coordinator – Kevin Black

    • Tag collection, bug hunting, testing, defining muon software for each official release

  • Muon Commissioning Software Manager – Kevin Black

    • Commissioning software configuration, prepare tags with developers, muon contact for Tier0 processing

  • US ATLAS Muon Analysis Forum Convener/ US ATLAS Muon Software Contact - Kevin Black

LPPC Harvard ATLAS Group

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Improvements and bug fixes

Offline community very active

Last month: 1205 new bugs in ATLAS code; 525 already closed

T0 people

complain about

large events

Kevin investigates and finds algorithm causing problems

Developer fixes

problem and provides tag

of fixed software

Code re-run

at T0

Collects tags to be used in

next cache (i.e. update)

Kevin tests tag

LPPC Harvard ATLAS Group

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Muon Track Segment Reconstruction

  • Good benchmark for software

  • (in real data)

Muon arrival time (t0)

not well defined

  • Partially corrects poor calibrations

  • Can be used in collision data until calibrations are satisfactory



  • Reconstruction in cosmic ray data

    • Problems:

      • Tracks do not point to IP

      • Cosmic rays not synchronized with LHC clock

      • Time of flight between chambers not constant

  • Developed new segment finding algorithm with floating t0

  • Code adopted by standard reconstruction

  • Responsible for the Muon Track Segment common code – Srivas Prasad

LPPC Harvard ATLAS Group

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Muon Track Segment Reconstruction

Internal note: A. Belloni, K. Black, J. Guimaraes da Costa, V. Martinez Outschoorn, S. Prasad, In-situ t0 calibration for MDT segments, ATL-COM-MUON-2009-006, CERN, 2009.

LPPC Harvard ATLAS Group

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Resolution studies

Old rt-relations

Crossing of multiple mezzanine cards

Average: 60 μm per week

10 μm per 12 hours

Temperature effects

Effect: 100 μm if not corrected (for 5 °C)

Effect: 10-50 μm (depending on how many mezz

cards are crossed)

Internal note: A. Belloni, K. Black, G. Brandenburg, J. Guimaraes da Costa, V. Martinez Outschoorn, S. Prasad, Muon Segment Studies: Calibration and Resolution, ATL-COM-MUON-2009-019, CERN, 2009.

  • Resolution not optimal due to several calibration issues:

    • Studied with toy MC and real data rt-relations and conditions

LPPC Harvard ATLAS Group

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Muon Detector Upgrades

  • LHC upgrade plans:

    • Phase 1: L= 3x1034 cm-2s-1 in 2014

    • Phase 2: L= 1035 cm-2s-1 in 2018 (Super-LHC)

  • Spectrometer designed for L= 1034 cm-2s-1 (with x5 background rate scale factor)

    • Actual background level in the cavern is unknown

    • If SF=5 or larger, the innermost chambers in Muon Endcap will have degraded performance even in phase 1

  • US ATLAS Muon Upgrade Working Group:

    • Frank Taylor, Dan Levin, Jim Bensinger, John Butler, John Huth, Vinnie Polychronakos, Joao Guimaraes, Eric Hazen, Jay Chapman

LPPC Harvard ATLAS Group

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MDT Electronics Upgrades

  • Very natural project for our group

    • LPPC electronics shop

    • Designed and produced current ASD chip and mezz cards

  • Collaboration with BU, UM and Max Planck Institute

    • Letter of Intent submitted to CERN by MPI (in the process of joining)

    • Electronics suitable to standard MDT chambers and small-tube option being pursued by MPI

  • Upgrades to the ASD chip (Harvard)

    • Reduce MDT deadtime, noise levels

    • Match the new smaller tubes with different shaping times

    • Short term goals: detailed study of signal processing chain at Phase 1 rates to determine how or if one should proceed with a new ASD

  • Upgrades to the TDC (BU) and CSM (UM)  requires new mezz cards

    • Addresses bandwidth rate limitation

  • MDT based track trigger  might require new ASD chip

    • Addresses the L1 trigger threshold sharpness

LPPC Harvard ATLAS Group

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Micromegas Technology

  • Spatial resolution ~ 100 m (track< 45°)

  • Good double track resolution

  • Time resolution ~ 5 ns

  • Efficiency > 98%

  • Rate capability > 5 kHz/cm2

Harvard is interested in the front-end electronics

Initial stages of design started with BNL

  • Being considered for phase 1 to cover the region were the CSC was descoped (4 layers instead of 8)

    • If successful can be used in Phase 2

  • Combines trigger and tracking functions

  • Technology being used by T2K and COMPASS

  • Challenges:

    • Going to large areas ~1m x 2m with industrial processes (cost effective)

    • Need cost effective front-end electronics, including custom ASIC design

  • US Collaboration: Arizona, Brookhaven, U. South Carolina, Brandeis, Harvard, MIT

LPPC Harvard ATLAS Group

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Micromegas upgrade at Harvard

Small chamber being setup by Mercurio, Brandenburg with help from Steve Sansone

LPPC Harvard ATLAS Group

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Plan for FutureTake good data efficiently!

Muon spectrometer is ready for data-taking later this year

Endcap channel coverage is now over 99%

Maintain DAQ responsibility for the MDT

Alberto Belloni (Deputy Muon DAQ Coordinator)

New postdoc

Provide quick online/offline monitoring feedback

See Melissa’s talk

Improve offline software tools

Kevin Black (Commissioning Software Coordinator/Muon Release Coordinator)

Start muon spectrometer upgrade activities

Use our knowledge of the muon system as a springboard for early physics analysis

LPPC Harvard ATLAS Group

The end l.jpg
The End

LPPC Harvard ATLAS Group

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Magnetic Field Studies

Need precise (< 0.5%) field map over 20 x 20 x 25 m3

  • Calculate the field from current in the coils

    • Perturbations due to iron structures evaluated numerically

    • Positions and shapes of the coils must be known to a few mm

      • Surveys not reliable under operations conditions

One barrel and two endcap air core toroids, with 8 superconducting coils

LPPC Harvard ATLAS Group

Magnetic field reconstruction l.jpg
Magnetic Field Reconstruction

  • 1730 3-dim. Hall probes are installed on the MDT chambers

    • Measure field to a precision of 5 gauss

    • Comparing the measurements with field simulation, one can fit the location of the coils

  • Harvard (Morii) collaborates with Saclay and Dubna on field fit and reconstruction

    • Not enough measurements to constrain endcap coil positions

    • 64 extra sensors added to endcap cryostat surface

    • May 2009: All probes commissioned and positions surveyed

LPPC Harvard ATLAS Group

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Current Magnetic Field Studies

Connections between the 8 ECT coils

Field 5 cm from loop

  • Characterization of magnetic field continues (Morii, Nehrkorn, Fountain)

    • Validation of FEM calculations of the field perturbations due to ferromagnetic materials in cavern

    • Detailed positioning of the ECT coils and the current leads geometry

    • Results: Inter-coil connections contribute with ~40-50 gauss at sensor positions (x10 sensor resolution) and will be added to the field simulation

LPPC Harvard ATLAS Group

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Muon Track Segment Reconstruction

Fitted t0





Internal note: A. Belloni, K. Black, J. Guimaraes da Costa, V. Martinez Outschoorn, S. Prasad, In-situ t0 calibration for MDT segments, ATL-COM-MUON-2009-006, CERN, 2009.

  • Code adopted standard reconstruction

    • Ran on over 300 million cosmic events taken by ATLAS

    • Allowed for further validation of the software from cosmic data

      • Uncovered other problems

    • Design hit resolution (~ 80 μm) achieved

      (fit of core distribution)

LPPC Harvard ATLAS Group

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Muon chamber single counting rates at LHC design luminosity

(Background SF = 1)

  • At SLHC rates:

    • Degradation of spatial resolution due to space-charge effects

    • Reduction of efficiency

    • Increased fake track segments

    • Radiation damage to electronics

    • Larger readout bandwidth than currently available

Phase 1 rate (with SF=5): 1.5 kHz cm-2

LPPC Harvard ATLAS Group

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Further upgrades

  • Bandwidth rate limitation

    • Upgrades to the TDC chip (BU)

      • Exploring FPGA implementation

        • Need to understand radiation hardness and SEU

    • Upgrades to the CSM (UM)

      • Upgrade to CERN GBT chip and new FPGA technology

    • These require new Mezzanine cards

  • Possibility of a MDT based track trigger

    • Addresses L1 threshold resolution

    • Could be implemented within the Mezzanine and CSM cards

      • FTK-type based trigger, allowing an ID-MDT match prior to L2

      • L1 implementation using coarse information from the MDT

        • Requires longer L1 latency

        • Likely to require a new ASD with two output streams: One going to the TDC, the other to a dedicated trigger processing unit to identify segments.

LPPC Harvard ATLAS Group