1 / 33

Status of the LHCb experiment

Status of the LHCb experiment. Andrei Golutvin ( Imperial & CERN & ITEP ) on behalf of the LHCb Collaboration. Outline: Introduction Detector Subsystems Trigger/Online/Computing Cost and funding issues Collaboration matters Physics goals in 2010. Brief Summary.

tashya-powers
Download Presentation

Status of the LHCb experiment

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. Status of the LHCb experiment Andrei Golutvin ( Imperial & CERN & ITEP ) on behalf of the LHCb Collaboration • Outline: • Introduction • Detector Subsystems • Trigger/Online/Computing • Cost and funding issues • Collaboration matters • Physics goals in 2010 RRB October 2009

  2. Brief Summary • The installation of LHCb is fully completed, including M1 station • All detector elements are commissioned and ready for data taking • Read out at 1 MHz successfully tested • Full Experimental System Test (FEST), which is able to inject • MC data to Event Filter Farm, is used for the HLT commissioning • Strategy for trigger and subsequent physics analysis of the • 2009-2010 Run is prepared • LHCb is fully operational for the Physics Run in 2010 RRB October 2009

  3. LHCb Collaboration 700 members 15 countries 52 intitutes RRB October 2009

  4. Beam Pipe (CERN)23 m long beam pipe consisting of 3 Be and 1 stainless steel sections • The procurement of a replacement beam pipe UX85/3B is underway • It is fully budgeted by CERN • Design of optimized beam pipe supports with reduced material is ongoing Magnet (CF) Warm dipole magnet with 4 Tm bending power along the beam axis • Magnet was powered in July and September 2009 to perform a survey • on the support of TT and RICH-1 shielding using CCD cameras. • Much improved stability  no other intervention on the support • structures needed RRB October 2009

  5. VErtex LOcator (CH,DE,GB,NL)2×21 pairs of Si sensors arranged in 2 halves; each pair consists of one sensor with R- and one sensor with -strips RRB October 2009 VELO is now ~100% operational • LV and HV system are operating stable LV spares situation substantially improved due to delivery of spares from CAEN • DAQ read out at 1 MHz • Online and offline monitoring finalized • Vacuum and cooling systems fully operational Until September 2009 the temperature was kept at -5°C. Lowered to the nominal -30°C for the recent TED RUN (completed Yesterday) in readiness for full data taking • VELO interlock box ready (including spare) • The build of the VELO replacement continues. ~50% of modules, capton cables and vacuum feedthroughs complete

  6. VELO experience with TED runs TI8 • - Transfer line External beam Dump • - Shots every 48 seconds • - Joint work with TT/IT/ST and SPD • - Typical occupancy of 7 clusters/sensor/event LHC • The procedure to tune • the timing tested with data • Timing accuracy < 2 ns can • be achieved with • ~ 100 clusters/sensor/step • Timing is monitored online RRB October 2009

  7. Evaluation of the distance between 2 VELO halves using TED data Very Preliminary Very Preliminary • Results with 255 tracks: • Histogram 2.163 mm • ( = 0.080 mm) • Milliepede 2.156 mm • The halves were moved by a “secret” amount (450 m). • Results with 852 tracks: • Histogram 2.611 mm • ( = 0.087 mm) • Milliepede 2.601 mm • VELO was moved by 445 ± 10 m RRB October 2009

  8. Outer Tracker – OT (CERN,CF,CN,DE,NL,PL)Three stations with each 4 stereo layers of straw tubes 5 mm diameter and 5m length; 55k channels • Outer Tracker is ready for data taking • Installation and test of FE electronics completed • OT read out at 1.11 MHz • HV test continued, 99.9% channels ok! • Likely a large fraction of remaining 0.1% can be recovered • The anti-ageing treatment of detector modules at 40°C in situ • has been completed. Gas system modified to allow an oxygen • admixture if necessary • Initial time and space alignment within expectations • The procedures for further offline improvements give expected • results. High level data quality monitoring is being finalized Muon Calo OT RRB October 2009

  9. Status of the Front End electronics (9 / 2009) - 2 FE boxes show high rate issues - 3 FE boxes (at the edge of acceptance) dismounted RRB October 2009

  10. OT spatial alignment using cosmics (using drift time information) without alignment with alignment T1 T2 T3 Alignment accuracy better than 100 mm using only 10k tracks RRB October 2009

  11. ST: Trigger Tracker & Inner Tracker (CERN,CH,DE,ES,UA) TT covers area of 1.41.2 m2; 4 stereo layers with ladders consisting of 3 or 4 chained Si- sensors with strip pitch 183 micron; 143k channels IT: 3 stations with 4 boxes each arranged around beam pipe; each box has 4 stereo layers x-u-v-x, modules with one or two chained Si-sensors; strip pitch 198 micron; 130k channels • ST is ready for data taking • After repair work during shutdown 99.7% IT channels and 98.6% TT • channels are operational • Both detectors successfully read out at 1 MHz • Detailed studies of detector performance using TED data; IT ladders • aligned to < 20 mm precision • Remaining concern is the broken bonds appearing on seven TT modules. • Four of the effected modules replaced with spares; three left in situ to • study the evolution in the pit. Order new hybrids in the next months. RRB October 2009

  12. Innermost bond row affected Effect not reproduced in the lab (despite of extensive studies applying vibrations & thermal cycling) • Possible causes: • Initial cracks due to the bonding process, typically occur at first bonds • Loop height (should be > 25%) RRB October 2009

  13. Three modules left in situ in order to study progress of the problem Order for new hybrids to be placed RRB October 2009

  14. ST analysis of TED data RRB October 2009

  15. IT ladders aligned to precision of ~14 mm • TT alignment requires better understanding of • VELO seeds • Expect from the analysis of recent TED run: • - Improved quality of VELO-TT & IT-TT tracks • - Improved timing RRB October 2009

  16. RICH (CERN,CF,GB,IT)RICH1 and RICH2 with 3 radiators covers momentum rRecent highlighange 2-100 GeV; RICH1: 5cm aerogel with n=1.03 & 4m3 C4F10 with n=1.0014; RICH2: 100m3 CF4 with n=1.0005; ~500 HPD to readout • Both RICH1 and RICH2 are complete, commissioned and waiting for data • Recent highlight is the observation of Cherenkov rings from the aerogel • and gas ( C4F10 ) radiators using cosmic rays  convincing test of the online • monitoring and offline reconstruction software. • Estimate of lifetime is well established process for each HPD. The details of • repair process of all degraded tubes agreed with DEP-PHOTONIS. • Tubes expected to fail in RICH-2 in 2009/2010 are being replaced (14 HPD available). • Timing alignment, in particular for RICH-2. • RICH-1 Magnetic Distortion Monitoring System tested. • Some HV supplies were showing short saturation glitches. Cause • identified by the manufacturer. All HV suppliers repaired. •  Overall stability is now satisfactory RRB October 2009

  17. LHCb RICH1 sees rings with cosmic rays (RICH1 has two radiators: aerogel and gas) Ratio of the rings radii corresponds to the ratio of the gas and aerogel refractive indexes Aerogel ring Gas ring RRB October 2009

  18. Excellent Signal/Noise of HPD (only a few out of ~105 active channels • were noisy). • Number of detected Cherenkov photons agree with expectations RRB October 2009

  19. Calorimeters (CERN,CF,ES,FR,RO,RU,UA)PS/SPD: 12k scint. tiles readout by WLS; ECAL: 6k shashlik cells; HCAL: TILE Calo, 1.5k channels • The four calorimeters system SPD/PS/ECAL/HCAL is fully operational • Much improved stability of the 6000 ECAL channels modified during • 2008/2009 shutdown. PMT gain measurements agree within 5% with earlier • test measurements  ~10% inter-calibration at the start-up • HCAL is inter-calibrated to <4% using the Cesium source • All calorimeters are successfully read out at 1 MHz • SPD/PS/ECAL/HCAL time aligned within 3 ns • Further improved using TED data • Emphasis on ECAL calibration procedures and data quality controls RRB October 2009

  20. Improved CALO timing using TED data Timing inside crate & Front End card PS / ECAL / HCAL aligned to < 1ns using TED data Fast improvement expected with a few millions events RRB October 2009

  21. Comparison of the ECAL PMT gain measured in situ with previous measurements (@ LAL and Hamamatsu) Mean: 2.3% R.M.S.: 11.4% (G(LED) – G(HAM)) / G(LED) PMT gain can be measured in situ using LED calibration system Taking into account that all modules have been measured at cosmics before the installation ECAL is inter-calibrated to ~ 10% at the start-up Several methods to reach 1% level using p0 signals have been tested with MC data RRB October 2009

  22. Muon (CERN,CF,IT,RU) Arranged in 5 SuperLayers; M1 consists of 12 double triple GEM chambers and 264 MWPC’s; M2-M5 consists of 1104 MWPCs • The installation of M1 station completed in time by July 7 • M1 commissioning is nearly completed; M1 included • in the global DAQ • HV systems operational • Commissioning of M2-M5 stations completed • Faulty readout channels fixed RRB October 2009

  23. M1 history in brief July 2009: installation completed September 2009: first data! 02 March 2009: cables and pipes… RRB October 2009

  24. Hardware level (L0) Search for high-pT μ, e, γ and hadron candidates Software level (High Level Trigger, HLT) Farm with O(2000) multi-core processors HLT1:Confirm L0 candidate with more complete info, add impact parameter and lifetime cuts HLT2: B reconstruction + selections Trigger & Online &Computing(CERN,CF,CH,DE,FR,ES,GB,IT,NL) Trigger is crucial as σbb is less than 1% of total inelastic cross section and B decays of interest typically have BR < 10-5 40 MHz L0 m L0 had L0 e, g Level -0 1 MHz ECAL Alley Had. Alley Muon Alley HLT1 High-Level Trigger 30 kHz Global reconstruction Inclusive selections m, m+track, mm, topological, charm, ϕ HLT2 & Exclusive selections 2 kHz RRB October 2009 Storage: Event size ~35kB

  25. L0 trigger rechecked following improvements in the MUON, CALO and DAQ • The integration of M1 underway. • L0×HLT1×HLT2 tuned to give an output rate below 2 kHz • (for MC data produced at nominal LHCb conditions @ 2×1032). • HLT farm has been increased to 550 processing units sufficient to • receive 1 MHz trigger rate at nominal event size. • The readout network expanded to nominal capacity. Completion of the farm • to reach its full CPU power will be decided in the beginning 2010. • New MC09 data sample prepared to mimic 2010 conditions. A total of 109 • min. bias and 100’s billion signal events run on the GRID. • Many improvements in the production system. • MC09 is being used to tune the trigger settings to the start-up and • first physics. Trigger is capable to efficiently select charm in addition • to the core B-physics programme. RRB October 2009

  26. Cost and Funding Overall cost remains unchanged at 75 MCHF The underfunding in 2005 of 2.6 MCHF for the DAQ CPU Farm, has been covered through extra contributions (BMBF Brazil, France, MPI Germany, Spain, UK, US and CERN) Budget forecast for M&O Cat. A for this year is correct for all the items except Online and Power estimates Collaboration Matters • Two new applications for Technical Associates: • - Catholic University of Rio de Janeiro, Brazil • - Tier-1 centre CCIN2P3, Lyon, France • Final decision is expected at the next CB in December 2009 • Guy Wilkinson (University of Oxford) elected as the next Physics • Coordinator starting from January 2010 RRB October 2009

  27. Physics goals in 2010 Early measurements - Calibration signals and minimum bias physics: 108 events Key channels available in min bias data with simple trigger: - Ks ππ 95% purities achievable using - Λ  pπ kinematical & vertex cuts ~ 40 mins @ 1031 With 2 kHz random trigger - J/ψ trigger on single muon with pt cut (600k ev./pb-1)  one muon unbiased for PID studies and momentum calibration - J/ψ physics & production cross-sections: ~ 1-5 pb-1 Measure diff. cross-section for prompt J/ψ and bb production cross-section (from secondary J/ψ) in region inaccessible to other experiments Λpπ RRB October 2009

  28. Physics goals in 2010 • Analysis commissioning in hadronic modes Detailed studies of Dhh (rehearsal for Bhh) - Separate Kπ, KK, ππ and DCS Kπ - Vertex and mass resolutions - Lifetimes Accumulate samples of BD(Kπ)π (“ADS” control mode) - Study background environment - Look for any evidence of B+ / B- asymmetries • Charm physics: 20 pb-1 and upward • ( Exciting possibilities even with low luminosity) • An example: flavour tagged D0KK events for measuring yCP • y = τ(D0  Kπ) / τ(D0  KK) – 1 • and corresponding CP asymmetry • LHCb can collect ~ 105 flavour tagged KK events with 20 pb-1 (same statistics • as BELLE with 540 fb-1 ). Similar data sets for many related channels: • D0ππ, KKππ, KSππ, KSKK, D+ KKπ … RRB October 2009

  29. Prospects for most competitive measurements in 2010 Bs μμ With data sample of ~200 pb-1 LHCb should be able to improve Tevatron sensitivity for Bs μμ and ϕs (present ‘central’value from Tevatron would be confirmed at 5σ level) ϕs RRB October 2009

  30. Conclusion • LHCb is ready for data taking • First data will be used for calibration of the detector and • trigger in particular. First exploration of low Pt physics • at LHC energies. Some high class measurements in • the charm sector may be possible with 50 pb-1 • With ~ 200 pb-1 data sample LHCb will reach Tevatron • sensitivity in a few golden channels in the beauty sector RRB October 2009

  31. RRB October 2009

  32. Calorimeter hardware status RRB October 2009

  33. M2-M5 channel map: 2008 vs 2009 A few missing logical channels in 2009 map due to wrong settings (too high threshold) M3 M4 M2 M5 2008 Noise rate per logical channel 2009 G. Graziani RRB October 2009

More Related