1 / 27

Integration and Commissioning of the ATLAS S emi C onductor Barrel T racker

Sofia Chouridou University of California, Santa Cruz On behalf of the ATLAS SCT Collaboration HSSHEP Workshop Athens, 28/3/07. Integration and Commissioning of the ATLAS S emi C onductor Barrel T racker. Contents. Layout of the ATLAS SCT Testing and Integration of the 4 SCT barrels

camilla-todd
Download Presentation

Integration and Commissioning of the ATLAS S emi C onductor Barrel T racker

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Sofia Chouridou University of California, Santa Cruz On behalf of the ATLAS SCT Collaboration HSSHEP Workshop Athens, 28/3/07 Integration and Commissioning of the ATLAS SemiConductor Barrel Tracker

  2. Contents • Layout of the ATLAS SCT • Testing and Integration of the 4 SCT barrels • SCT barrel and Transition Radiation Tracker (TRT) Integration • Cosmic tests at the surface building (SR1) at CERN • Summary and plans Sofia Chouridou, University of California Santa Cruz

  3. AToroidal LHC ApparatuS • A general purpose LHC detector • p-p collisions at 14 TeV CM Energy • Bunch crossing every 25 ns • L = 1033 – 1034 cm-2 s-1 • Starting date: 2007 Sofia Chouridou, University of California Santa Cruz

  4. ATLAS Inner Detector and Silicon Tracker • Inner Detector • Axial Magnetic field 2 Tesla • Pixel Detector (r = 5-25 cm) • Semiconductor Tracker (r = 25-50 cm) • Transition Radiation Tracker(r = 55 –105cm) • Semiconductor Tracker(SCT) • 4 cylindrical barrel layers • 2 X 9 endcap disks • Hermetic coverage |η| < 2.5 • 4088 silicon modules • 16000 single sensors • 6.3 million read-out channels • Ambient temperature: -70 • Resolution: • - σ (rφ) = 16 μm • - σ (z) = 580 μm Sofia Chouridou, University of California Santa Cruz

  5. SCT Modules Barrel module • Siliconmicrostrip pinn detectors • 768 ac-coupled readout strips • Pitch size - 80 μm (barrel) - 57 – 90 μm (endcap) 4 different module types • 1 barrel type • 3 endcap (forward) types - outer - middle - inner Difference between types • Geometry (mainly) • Different radial position on disk Middle forward module Sofia Chouridou, University of California Santa Cruz

  6. Barrel Module Design and Hybrid Detector part and support • 4 single sided silicon sensors (Hamamatsu) • Thickness: 285 μm • Length of strips : 12 cm • Baseboard (TPG) sandwiched between the two detector pairs • mechanical base / heat spreader • Mounting holes on the beryllia facings • Relative angle of sensor pairs 40 mrad • providing two-dimensional position info Hybrid • Cu/Polyimide flexible circuit • Wrapped around the detector/baseboard • Supported by a rigid carbon-carbon bridge • Supports the 12 binary readout ASIC chips • 6 on each side • each chip reads out 128 channels • radiation hard DMILL technology • Optical links are used for CLK/COM + data transmission • 2 opto chips on a small optical hybrid near the module • Connected with a pigtail to the module Sofia Chouridou, University of California Santa Cruz

  7. Assembly of modules in 4 barrels (Oxford) • After extensive QA tests, all barrel modules were shipped to the macro-assembly site in Oxford • Careful selection of modules based on production and acceptance tests • Modules were mounted on 4 cylindrical support structures (barrels) by 2 custom robots • Very restricted clearances between the modules and support structures • Continuous testing during and after assembly of the Barrels 3, 4, 5 and 6 • 4 complete barrels were shipped to CERN (March 05- August 05) A barrel close-up Module connector Module Cooling pipe Sofia Chouridou, University of California Santa Cruz

  8. SR1 integration area infrastructure (CERN) • SR1 is a large clean room shared by the 3 ID groups (SCT, TRT, pixels) • Thermal enclosure (dry-air flush) for barrel testing • Evaporative cooling system (C3F8) • Power Supplies (LV and HV) and readout hardware (a subset of • those to be used in ATLAS) • Interlock systems • Control room with Detector Control System (DCS) PCs • and the DAQ PC Barrel4 at SR1 Sofia Chouridou, University of California Santa Cruz

  9. Preparations and initial tests • Visual inspection soon after the arrival at SR1 • Barrel brought into thermal enclosure • Harnesses (electrical services) tests • Power cables, fibers, DCS, cooling connections • Leak tests of cooling loops • DCS sensors tests • Barrel cooled down to ~10 0C • Power Supplies ON • The fun starts! Sofia Chouridou, University of California Santa Cruz

  10. DCS and Cooling Monitoring Dewpoint and temp. in enclosure Temperature sensors on pipes Power Supplies monitoring Always pay attention to any monitoring warnings and alarms to ensure the correct functionality of all systems involved!!! Sofia Chouridou, University of California Santa Cruz

  11. More Barrel Tests… • Digital tests • Identify chip or hybrid malfunction • Check the communication/data links with the modules • Analogue tests • Use of internal calibration circuit to inject charge of adjustable amplitude in the preamplifier of each channel • Use the corrections of the channel-to-channel threshold variations (trim DAC in chip) that were calculated during the QA of the modules • Binary front-end chip -> occupancy Vs threshold scan -> s-curves • Gain, offset, equivalent noise charge(ENC) for each channel • Noise Occupancy - Probability for a strip to give a noise hit for a certain event - Threshold scan without input charge - < 5 x 10-4 at 1fC nominal threshold Sofia Chouridou, University of California Santa Cruz

  12. Results and Milestones • 99.7% of the 3.2 million readout channels of the SCT barrel are fully functional! • ENC ~ 1480 e- (cold tests: Thybrid = 12 0C) • ENC ~ 1600 e- (warm tests: Thybrid = 28 0C ) • Gain ~55 mV/fC • Noise Occupancy: typically a few X 10-5 Comparison of the SR1 results with the Oxford macro-assembly data was excellent!! • First B5 then B4 and finally B3 were inserted into the largest B6 • The SCT barrel was inserted into the TRT on the 17th of Feb. 06 Sofia Chouridou, University of California Santa Cruz

  13. Some wonderful memories… Insertion of SCT into TRT, Feb06 Insertion of B4, Sep05 Barrel ready for Cosmic tests, May06 SCT-TRT barrel Sofia Chouridou, University of California Santa Cruz

  14. Configuration for Cosmic Tests at SR1 Scint 1 Figure not to scale SCT • 467 of 2112 modules ~ 1/4 of SCT barrel • Keep detector dry using dry air into its thermal enclosure TRT • 2 X ~6600 Channels ~ 1/8 of TRT barrel • Trigger provided by 3 scintillators • Scint. 3 provides a cleaner sample • thanks to longer TOF and allows a • momentum cut (~200MeV) Scint 2 Scint 3 Sofia Chouridou, University of California Santa Cruz

  15. A brief list of studies • TRT and SCT standalone tests • Mainly online checks (eg. SCT characterization, TRT board tests) • Some standalone cosmics runs • Combined noise and X-talk tests • Common TDAQ readout of SCT and TRT • Implementation of common trigger • Synchronous readout of 4 SCT barrels and SCT+TRT • Noise on SCT from TRT + Noise on TRT from SCT • Cosmics • Timing studies: synchronization of SCT/TRT read out • Data taken with top sectors SCT+TRT • Data taken with top + bottom sector SCT+TRT • Test of full reconstruction chain • Efficiencies and noise occupancy • Alignment and residuals on SCT and TRT Sofia Chouridou, University of California Santa Cruz

  16. SCT Online Monitoring Implementation of Monitoring Tools in ATHENA • ATHENA is the ATLAS Offline Software Framework • Event Filter (EF) is the third and final ATLAS trigger stage • Farm of computers that run event Processing Tasks (PTs) • Provide trigger decisions, event analysis and reconstruction • The monitoring tools developed can run online as Athena PTs • Producing histograms to check detector performance (noise, hit maps, efficiencies, resolution, synchronization, etc) • At SR1 one simple trigger stage was used and treated by the tools as the EF • Application and use of these monitoring tools in final ATLAS set-up How does it work? • The monitoring software sends periodically updated histograms to the Online Histogram Server (OHS) • An Interactive GUI (Online Histogram Presenter(OHP)) collects and displays them • Same principle for the TRT, global Inner Detector Monitoring and ATLAS Sofia Chouridou, University of California Santa Cruz

  17. Atlantis Event Display • The Atlantis Event Display run online during the combined SCT and TRT tests • Excellent online (and offline) monitoring tool • Not only supplementary to the monitoring histograms but also necessary for various checks of data quality A cosmic muon passing through the SCT and TRT barrel at SR1 Sofia Chouridou, University of California Santa Cruz

  18. CTB Tracking • The CTB- tracking was developed during the Combined Test beam at CERN in ‘04 and it is used for the SR1 cosmic data reconstruction • No magnetic field -> muons move in straight lines • Tracks do not originate at the center of the detector • It has a GlobalChi2 fitter that minimizes the track residuals • Residuals = the distance between the measured position of the hit and the position as predicted by the fitted track • It can take energy loss and multiple scattering into account • Highly momentum dependent effects • Momentum is not known at the SR1 cosmic setup • Very hard to reject the low energy part of the spectrum (limited space and weak floor strength prevented the use of a decent absorber e.g 1m of lead for a 1 GeV cutoff) • This functionality is disabled • Track parameter uncertainties can not be properly estimated The correct detector resolution can not be extracted by these data Sofia Chouridou, University of California Santa Cruz

  19. Alignment Algorithms • Minimize the track residuals in an iterative procedure • Upon convergence the final alignment constants are stored • Usually 6 Degrees Of Freedom (DoF) per module: 3 translational + 3 rotational • Global χ2 • Minimizesthe χ2 from a simultaneous fit to all track and alignment parameters • Module correlations • Local χ2 • Minimizes the χ2 of alignment parameters for each module • Correlations are taken into account through iterations • Robust • Uses mainly residuals from hits in adjacent overlapping modules (overlap residuals) Sofia Chouridou, University of California Santa Cruz

  20. Hit Efficiency • For each layer (barrel): • Efficiency = No of HitsObserved / No of HitsExpected > 98.8 % • Nominal geometry (empty circles) • Global χ2 (squares) • Local χ2 (filled circles) • Robust (triangles) The Global χ2 gives the best performance Layer2side1 Layer3side0 Layer3side1 Layer0side0 Layer0side1 Layer1side0 Layer1side1 Layer2side0 Sofia Chouridou, University of California Santa Cruz

  21. Unbiased Residuals using alignment info Unbiased residual = a residual where the hit does not participate in the track fit Global χ2 Local χ2 Robust • MC σ ~ 23 -39 μm • Data without alignment • σ ~ 75 -110 μm The SCT alignment algorithms work very well (so far) The Global χ2 has the smaller residuals ~ 40-85 μm Sofia Chouridou, University of California Santa Cruz

  22. Noise Occupancy measured by a calibration run • Using the internal calibration circuit of the chips an occupancy Vs threshold scan without input charge is performed Run 2981 6.93x10-5 4.49x10-5 5.72x10-5 6.28x10-5 5.81x10-5 NO is well within the specifications < 5 x 10-4 Sofia Chouridou, University of California Santa Cruz

  23. Noise Occupancy measured by cosmic runs • Noise Hits = All Hits – Hits associated to a track • Noise Occupancy per event = Noise Hits / modules * strips * events Run 3080 10K events 5.89x10-5 5.43x10-5 5.47x10-5 5.72x10-5 NO for all layers = 5.85x10-5, compatible with calibration scan calculation Sofia Chouridou, University of California Santa Cruz

  24. Noise Occupancy in some cosmic runs • Chips threshold set to 1 fC as derived from the 10PointGain function Sofia Chouridou, University of California Santa Cruz

  25. Noise runs conditions… The noise was also tested for several different conditions: • TRT was ON or OFF • Noise runs where the trigger rate (produced by a pulser) was varied from 5 Hz to 50 KHz • All hits are noise hits, no tracks present • Noise runs where trigger rate = 500 Hz and the threshold varied (0.9 - 1.05 fC) • Electrical heaters ON/OFF and switching between the two states • Pads surrounding the SCT cold thermal enclosures keeping the temperature of their outer surfaces above the dew point • Different grounding schemes No increase of noise was observed in any of these configurations! As the SCT/TRT barrel showed a very good behaviour at SR1, we finally allowed it on the 23rd of August ‘06 to go… Sofia Chouridou, University of California Santa Cruz

  26. …home! ATLAS pit Sofia Chouridou, University of California Santa Cruz

  27. Summary, Current Status and Plans • The integration of the SCT and TRT barrel was successfully performed at SR1 at CERN • The cosmic tests at SR1 proved the very good performance of the barrel; a very important and successful exercise before the installation and commissioning in the pit • The commissioning of the Inner Detector barrel has been continued during the last few months down in the pit • Power cables and fiber connections completed • Tests of the connections • Verification of good functionality by powering it (on-going) • Tests with cosmics in the pit are going to start around May • A very important step towards LHC data taking We are looking forward to the first real data !! Sofia Chouridou, University of California Santa Cruz

More Related