9 November 2005
LARGE HADRON COLLIDER COMMITTEE
1. Status of the LHC Machine: Lyn Evans
2. LHCf Technical Proposal: Yasushi Muraki
3. LCG Status Report: Frederic Hemmer
Present: S. Bertolucci (Chairman), K. Borras, S. Dalla Torre, J. Engelen, M. Gonin, J. Haba, V. Kekelidze, J. Knobloch, R. Landua, M. Mangano, J. Martin, M. Martinez-Perez, P. McBride, C. Niebuhr, B. Peyaud, K. Potter, C. Rembser, D. Schlatter, S. Smith, E. Tsesmelis (Secretary), C. Vall??e
Apologies: P. Dauncey, S. de Jong
The Chairman thanked the outgoing members K. Borras, J. Martin, P. McBride and C. Vall??e for their dedication and invaluable assistance provided as members of the LHCC.
The Chairman welcomed the new members S. Dalla Torre and M. Gonin to the Committee.
The minutes of the seventy-seventh LHCC meeting (LHCC 2005-026 / LHCC 77) and the report from the CMS Comprehensive Review (LHCC 2005-027 / LHCC-G-097) were approved.
2. REPORT FROM THE CHIEF SCIENTIFIC OFFICER
The Chief Scientific Officer (CSO) reported on the LHC Project. Good progress was reported on the installation of the LHC with two sub-detectors of the QRL cryogenic line installed and tested and more than one-hundred main dipole magnets already in their final positions in the tunnel. The accelerator remains on schedule for collisions in the summer of 2007. Any refining of the LHC machine schedule will take place in the spring of 2006. He also reported that the commissioning of the Low Energy Ion Ring (LEIR), which is central to the LHC ion injector chain, has started successfully. The appointment of an LHC Physics Coordinator will be confirmed by the end of January 2006.
The next sessions of the experiment and computing Resource Review Boards will be held in mid-October. Among the issues to be discussed is the availability of the required computing resources around the world for the LHC start-up. The actual LHC running will have implications on the computing installations.
3. REPORT FROM THE ALICE REFEREES
The LHCC heard a report from the ALICE referees, concentrating on the sub-detector progress and the Space Frame load tests.
The Committee heard a report on the general progress of the ALICE experiment. All chambers of the Time Projection Chamber (TPC) have been mounted and production and testing of the front-end electronics is advancing well. The mechanical support structures and services for the High Momentum Particle Identification Detector (HMPID) have been pre-assembled at Point 2. The Muon Dipole Magnet has been commissioned in its final position and the magnetic field mapping together with the Solenoid Magnet is in progress. Design of the read-out board for the Transition Radiation Detector (TRD) has been finalized and production has started. Good progress was reported on the Time-of-Flight (TOF) detector with production of strips well-underway, and with module assembly and the production of the front-end electronics having started. The new batch of the MANAS read-out chip for the muon trigger front-end boards exhibit a good pedestal and gain distribution. Additional checks on more chips from the same batch are in progress and production of MANAS chips continues with improved control of the processing environment. Boards for the Central Trigger Processor have been delivered and the data acquisition system for early commissioning of the ALICE experiment will be moved to Point 2 at the beginning of 2006.
The referees also reported on the final Space Frame load tests. The smaller measured deformations compared with those calculated are attributed to the mechanically stronger material used in the final Space Frame construction. The exercise has provided the optimal sequence of loading the Space Frame with TRD and TOF modules.
The Committee also heard a report on the Forward Detectors. Irradiation of the V0 detector components in radiation fields shows that the light attenuation after an irradiation equivalent to 10 years of LHC operation is limited to 20% and can be compensated by an increased high voltage on the photomultiplier tubes. Spare wavelength shifting fibres will be procured. Good progress was reported on the production of the prototype and beam tests of modules and on the read-out electronics of the Forward Multiplicity Detector (FMD).
The referees also reported on the Inner Tracking System (ITS). One sector of the Silicon Pixel Detector (SPD) is complete and good progress was reported on the production and test of components, the assembly of the half-staves and sectors and the sector integration and commissioning. Concerns remain on the available manpower and support for the wire bonding phase. Production of the Silicon Strip Detector (SSD) is advancing. Production and assembly of Silicon Drift Detector (SDD) modules are also advancing well. The start of ladder assembly has been delayed due to the unavailability of ladder long cables and the critical factor in ensuring on-time completion of the detector is the sensor production rate at CANBERRA. The revised ITS schedule will be available in January 2006 once production has progressed further.
4. REPORT FROM THE CMS REFEREES
The LHCC heard a report from the CMS referees, concentrating on the general progress of the sub-systems, and the overall schedule and milestones.
The referees reported on the status of the Electromagnetic Calorimeter (ECAL). The delivery of crystals from the initial BCTP contract is complete and new contracts with BCTP and SIC have been signed to fulfill the total crystal requirements for the ECAL Barrel (EB) and End-cap (EC) detectors. Delivery of crystals from these new contracts has already started and the crystals are found to be of good quality. The problems associated with root porosity on some welds on the internal cooling manifolds of the ECAL have been resolved by introducing electron beam welding of the small pipes from inside the cooling block. The Supermodules already assembled will have to be retro-fitted and the schedule to fix the cooling blocks is reasonable. Good progress was reported on the EB and EC read-out electronics and on the installation of auxiliary systems. The revised ECAL schedule has no contingency left for the installation of EB+ in CMS.
Good progress was reported on the Muon Spectrometer. Production of Barrel Drift Tubes (DTs) and Resistive Plate Chambers (RPCs) is advancing well and their commissioning in SX5 has started but more resources are needed. Good progress was also reported on the construction of the End-cap RPCs RE2 and RE3 but their installation in CMS on the surface is tight. Installation of Cathode Strip Chambers (CSCs) is progressing and commissioning with cosmic-rays is well-underway. Delivery of MINICRATE electronics for the DT is now progressing well. Cabling for the RPC trigger is behind schedule due to delays in the procurement of material. Preparations of the cable chains underground is becoming critical. Installation of muon chambers in CMS is on-going, but is being managed together with the SX5 schedule changes arising from delays in the magnet preparation.
The referees also reported on the status of the CMS magnet. The magnet was successfully swiveled into the Barrel Yoke and is now installed in the outer vacuum tank. The overall magnet schedule is currently 6 weeks behind the CMS Master Schedule v34.2 and as many one-off steps are still to come, it is difficult to make more precise estimates of the schedule.
The Committee also heard a report on the Tracker. Production of components, including sensors, hybrids, modules and support structures, for the Tracker Inner Barrel (TIB), Tracker Outer Barrel (TOB), and Tracker End Cap (TEC) is progressing well. Following an investigation, problems with the Read-Out Driver (ROD) front-end electronics for the TOB have been resolved. A new critical phase is about to start at CERN with the arrival of the first TIB modules and RODs. The Tracker Integration Facility is being constructed and integration of the various Tracker components will start in November 2005. Commissioning of the Tracker will start in March 2006. The strengthening of the integration and commissioning teams should continue. Construction of the Tracker is scheduled to be finished in February 2006 with the last of the TEC Petals being assembled.
5. REPORT FROM THE LHCb REFEREES
The LHCC heard a report from the LHCb referees, concentrating on the status of the detector construction.
The referees reported on the tracking system, consisting of the Vertex Locator (VELO), the Trigger Tracker (TT), the Inner Tracker (IT) and the Outer Tracker (OT). The VELO vacuum system is progressing well and production of the detector halves is approaching the integration phase. However, production of modules and front-end electronics is on the critical path due to delays in the delivery of sensors, hybrids and pitch adapters. The VELO schedule remains tight. The LHCC took note of the planned VELO full system test and test beam run in 2006 as part of the detector?Ĵs commissioning plan. Series production of the TT modules has started and about 18 pre-series IT modules have been produced. Production of the OT modules and electronics is advancing according to schedule. Following the decision not to use CF4, due to its ageing properties, tests on the performance of the new gas mixture are on-going.
The LHCC also heard a report on the Ring Image Cherenkov (RICH) detectors. The prototype beryllium spherical mirror has been delivered and the order has been placed for the remaining seven mirrors. Transport of the RICH-2 to Point 8 is scheduled for mid-November 2005. Production of the Hybrid Pixel Detectors (HPDs) is underway and 21 tubes have been delivered and are within specification.
The referees also reported on the Muon System. Production of Multi-Wire Proportional Chambers (MWPCs) is running at all six sites and a good quality has been achieved. However, due to delays in the production, the LHCb installation schedule foresees staging of the M1 chambers. Installation of the Muon System infrastructure has started but with a delay due to the later than expected removal of scaffolding for the LHC machine cryogenics line in the UX85 experimental cavern. The LHCb installation schedule is being revised to take into account the delays resulting from the LHC machine cryogenics line. About three months delay to LHCb has been estimated and this will be recovered by shortening the LHCb global commissioning by the equivalent time to 3 months in total.
The Committee also heard a report on the Trigger and Data Acquisition. LHCb has successfully verified the power, cooling, control and monitoring of the computing farm and benchmarked the trigger algorithms for the Level-1 and Higher Level Trigger (HLT) during the real-time trigger challenge in July 2005. The LHCC took note of the LHCb proposal to read out all detector components with a trigger Level-0 rate of 1 MHz by combining the Level-1 trigger and HLT to one software trigger level. An Addendum to the LHCb Online Trigger Technical Design Report will be submitted and presented to the LHCC.
6. REPORT FROM THE LHCf REFEREES
The LHCC heard a report from the LHCf referees. In its Technical Proposal, the LHCf Collaboration puts forward a measurement of photons and neutral pions in the very forward region of the LHC in an effort to provide information for the elaboration of the cosmic-ray spectrum in the high energy region and for the determination of the primary composition of cosmic-rays. The measurements may also be used to calibrate Monte Carlo event generators, especially in the forward region. The LHCC considers that the physics goals of the experiment are valuable. The referees noted specific issues relating to the physics measurements, backgrounds, detector design and performance, and integration with the LHC Machine. Following further discussions with the LHCf Collaboration, the referees will make a further presentation at the next session of the LHCC.
7. REPORT FROM THE FP420 REFEREE
The LHCC heard a report from the FP420 referee. In its Letter of Intent, the FP420 Collaboration puts forward an R&D proposal to investigate the feasibility of installing proton tagging detectors in the 420 m. region at the LHC. By tagging both outgoing protons at 420 m. a varied QCD, electroweak, Higgs and Beyond the Standard Model physics programme becomes accessible. A prerequisite for the FP420 project is to assess the feasibility of replacing the 420 m. interconnection cryostat to facilitate access to the beam pipes and therefore allow proton tagging detectors to be installed. The LHCC acknowledges the scientific merit of the FP420 physics programme and the interest in its exploring its feasibility.
8. REPORT ON THE COMPUTING TECHNICAL DESIGN REPORTS
The LHCC heard a report from the LCG referees focusing on the review of the Computing Technical Design Reports.
Following the submission of the five computing Technical Design Reports (ALICE, ATLAS, CMS, LHCb, LCG) in June 2005, the LHCC, together with external experts, held a joint review of the documents on 7 and 8 October 2005, concentrating on the computing models, resource requirements, manpower, milestones and management. The review process is still on-going and its final report will be available for the November 2005 LHCC session. The following represent preliminary observations from the review:
?? The Technical Design Reports contain reasonable conceptual designs of the computing systems. These models, however, remain essentially untested but much will be known by September 2006 as many system tests, including tests of large-scale distributed analysis, are planned to be completed by then.
?? The Review Committee supports the first steps of the transition of the LCG towards a global LHC ?Ĳcomputing centre?Ĵ.
?? The balance amongst the experiments for resources outside of CERN will be difficult to achieve. An estimate of the missing resources for each experiment has been made. ALICE is missing about 50% of the required resources from outside of CERN. The LHCC does not see any significant difference in the fundamental computing needs between ATLAS and CMS. The difference in their requests depend mainly on the details of the computing models in the use of disk versus tape. This is a concern and must be resolved.
?? The Review Committee urges the computing management to proceed with caution and to re-evaluate the resources planning regularly so that most computing resources are purchased only when needed.
?? A plan is needed to support the computing and software infrastructure after the funding for Enabling Grids for E-sciencE (EGEE) and other GRIDs comes to an end. This should be included in the Memorandum of Understanding process.
?? Planning for computing needs to be linked more strongly to the physics needs of the experiments.
?? The Service Challenges (SCs) form the backbone of conditioning plans for the World LCG. The SC-3 is underway but is one month behind schedule and much work remains to be done.
?? All experiments have included a CERN Analysis Facility in their computing models. This facility will be important for calibration and alignment and for early user analysis and a strong management of the systems will be required.
9. TEST BEAMS
The SPS and PS Coordinator reported on the test beams.
Progress was reported on the repair of the PS main magnets. The first of such magnets have been repaired and re-installed into the PS machine. The plan is to now repair 20 magnets by the end of 2005 and then six-to-eight magnets per year from 2007 onwards.
The Coordinator also showed the accelerator schedule for 2006 as approved by the Research Board in September 2005. The PS is scheduled to run for physics from 22 May to 5 November while the SPS will run from 15 June to 5 November. The accelerator complex will then be put on stand-by in view of the LHC Injection Tests at the end of November and beginning of December.
10. ATLAS COMPREHENSIVE REVIEW
Since the previous ATLAS Comprehensive Review in July 2004, the ATLAS Collaboration has made very significant progress towards the realisation of an experimental set-up ready to record proton-proton collisions at the LHC in 2007. In particular, construction of the majority of the final components is either well-underway or completed, installation of the technical infrastructure in the underground caverns is well-advanced, installation of the first sub-detector elements of the ATLAS experiment in the underground cavern has been successful, and commissioning of the ATLAS experiment has started successfully. The procurement of the front-end electronics has in general been successfully completed.
It is realistic to expect ATLAS to have an initial working detector for the start of LHC operation in 2007, although detector installation can be foreseen beyond this date. However, the LHCC considers that the ATLAS plan to have installed and commissioned an initial working detector by the end of June 2007 is challenging, as a number of systems no longer have any contingency in the schedule, originally included as a safety margin for their installation. The LHCC observes that additional resources, both in terms of money and manpower, would aid in completing the initial detector.
Detector elements not installed by the LHC start-up in 2007 will be staged. The staging plan consists of deferring installation of some components of the Inner Detector, the Calorimetry, the Muon Instrumentation, the Higher-level Trigger, DAQ and the radiation shielding. Their installation in a long shutdown, while requiring additional resources, would complete the ATLAS detector as described in the approved Technical Design Reports.
The sixth of the LHCC Comprehensive Reviews of ATLAS took place on 10-11 October 2005. The LHCC referees addressed the following areas: Inner Detector, Calorimetry, Muon Spectrometer, Trigger and DAQ, Physics, Software and Computing, Installation and Technical Coordination, Commissioning and Combined Test Beam Results and the issues of Management, Magnet Systems and Electronics.
The conclusions and concerns of the LHCC are given below. They will allow the Committee to follow-up outstanding issues and to monitor future progress of this project in upcoming sessions of the LHCC prior to the next ATLAS Comprehensive Review.
?? Construction of the Inner Detector is advancing well and several outstanding problems have been solved since the previous Comprehensive Review. The one major concern is with the corrosion in the stave cooling pipes of the Pixel detector. Solutions to this problem have been identified, but the Pixel project has some considerable risk in not being completed on time.
?? Significant progress since the last ATLAS Comprehensive Review was reported on the ATLAS Calorimeters. The major outstanding problem area is related to the timely delivery of the high and low voltage power supplies.
?? Good progress was reported on the Monitored Drift Tube (MDT), Cathode Strip Chamber (CSC), Resistive Plate Chamber (RPC) and Thin Gap Chamber (TGC) detectors and a significant number of chambers, together with their front-end electronics, have been produced. The major outstanding concern remains the timely completion of the MDT chambers and the adherence to a strict quality control procedure for the RPC chambers.
?? No major concerns were expressed for the Calorimeter Trigger, Muon Trigger, the Higher-Level Trigger and the DAQ, but the schedule to complete the Calorimeter and Muon Triggers remains tight.
?? Significant progress was reported on the Physics, Software and Computing, with no major concerns having been identified.
?? Impressive progress was reported on the installation of ATLAS sub-systems at Point 1 and commissioning of the ATLAS detector has started. The revised ATLAS Installation Schedule is realistic but tight as contingency in the time to install the detectors prior to the end of June 2007 has been significantly reduced.
?? Excellent progress was reported on the ATLAS commissioning and on the Combined Test Beam.
?? The LHCC congratulates the ATLAS Collaboration for the significant progress since the previous Comprehensive Review. Should the total Cost-to-Completion not be covered, detector elements not installed by the start-up of the LHC in 2007 will be staged.
Following changes to the LHCC membership, the new referee teams are as follows:
ALICE: P. Dauncey, M. Gonin, J. Haba (Co-ordinator)
ATLAS: F. Forti, V. Kekelidze (Co-ordinator), R. Landua, M. Martinez-Perez
CMS: S. de Jong, R. Mankel, S. Smith (Co-ordinator), R. Yoshida
LHCb: S. Dalla Torre, C. Niebuhr, B. Peyaud (Co-ordinator)
TOTEM: S. Dalla Torre
MOEDAL: B. Peyaud
LHCf: M. Mangano, C. Niebuhr
RD39: S. de Jong
RD42: V. Kekelidze
RD50: R. Yoshida
LCG: P. Dauncey, F. Forti (Co-ordinator), R. Mankel, M. Martinez-Perez
12. DATES FOR LHCC MEETINGS
Provisional Dates for 2005:
Provisional Dates for 2006:
15- 16 February
- ALICE Physics performance Report Volume II (LHCC-2005-030/TDR 13)
- Measurement of photons and neutral pions in the very forward region
- ATLAS Comprehensive Review (LHCC-2005-033/G-100)*
* restricted circulation
Tel. 78949, 164057
LHCC Secretariat: Janet Grant (Bldg. 14/4-022) Tel. 73424