31 October 2001
LARGE HADRON COLLIDER COMMITTEE
Minutes of the fifty-fourth meeting held on
Wednesday and Thursday, 3-4 October 2001
1. ALICE Transition Radiation Detector Technical Design Report: J. Stachel
2. LHCb Status Report: T. Nakada
3. LHCb Outer Tracker Technical Design Report: B. Koene
The minutes of the fifty-third LHCC meeting (LHCC 2001-020 / LHCC 53) and the LHCC report on the ATLAS Comprehensive Review were approved without modification.
The Research Director for Collider Programmes reported on issues being currently considered to appraise the status of the LHC programme. He stressed that the LHC Project is keeping to the existing approved schedule and that only technical difficulties would provide a reason to change. A plan to completion is being prepared by CERN with the aim of submitting it to the next session of Council.
The LHC computing resources will be addressed in the context of the newly-approved LHC Computing Grid Project. Les Robertson has been appointed Project Leader.
The Research Director for Collider Programmes warmly thanked the outgoing
Chairman, Jos Engelen, for the magnificent job that he has done in wisely
steering the LHC experiments in the past 3 years. M. Calvetti has been
appointed as his successor.
2. REPORT FROM THE ALICE REFEREES
The Committee heard a report from the ALICE referees, concentrating on their preliminary reactions to the TDR for the Transition Radiation Detector (TRD). ALICE claims that the TRD, in conjunction with the Inner Tracking System (ITS) and the Time Projection Chamber (TPC), will provide electron identification in heavy-ion running in the central barrel region at momenta in excess of 1 GeV/c. In addition, the TRD could be used to trigger on high-pt (> 3 GeV/c) particles, thus providing not only enriched samples of gamma particles, but also the capability to select jets. Finally, the TRD could contribute significantly to the ALICE proton-proton physics programme, and in particular to charm and beauty physics, to the topological trigger function for the High Momentum Particle Identification Detector (HMPID) and to the measurement of jets.
Following further questions and discussions, the referees will make a full report on the TRD TDR at the next meeting of the LHCC.
The referees also provided updates to the status of the sub-systems and reviewed their milestones. The ALICE Collaboration has submitted reports to the LHCC documenting the status of key milestones.
3. REPORT FROM THE ATLAS REFEREES
The Committee heard a report from the ATLAS referees, concentrating on developments since the recent Comprehensive Review. Good progress was reported on various of the sub-systems, including the TRT production, availability of passive storage space for the Tile Calorimeter modules, clean-room facilities for the Inner Detector integration, and progress on the MDT production and quality control. The referees reiterated their concern about the delays in the stacking and cold tests for the LAr calorimeters and noted that the completion of the electromagnetic Barrel and End-cap A calorimeters are critical. The referees reported on the preliminary list of milestones that will be submitted to the LHCC at the end of October.
The LHCC considers that the initial detector proposed by ATLAS to be commissioned in time for the physics run scheduled to start in August 2006 is capable of searching for the Higgs and SUSY at the 10 fb-1 luminosity level, although installation of the staged items is necessary at increased luminosities. The Committee also acknowledges that although the initial ATLAS detector requires more resources in addition to those currently available, both in terms of money and manpower, any further staging of detector elements would severely limit the ability of the experiment in its search for Higgs and SUSY.
4. REPORT FROM THE LHCb REFEREES
The Committee heard a report from the LHCb referees, concentrating on the reviews of the TDRs for the Vertex Locator and Muon System. The Vertex Locator will provide precise measurements of track coordinates close to the interaction region to be used to reconstruct production and decay vertices of beauty- and charm- hadrons, to provide an accurate measurement of their decay lifetimes, and to measure the impact parameter of particles used to tag their flavour. The VELO measurements are also a vital input to the second level trigger, which enriches the b-decay content of the data. The Muon System will provide the muon triggering and offline muon reconstruction, fundamental requirements of the LHCb experiment since muons are present in the final states of many CP-sensitive B decays.
The referees also reported on their preliminary reactions to the TDR for the Outer Tracker detector. LHCb claims that the Outer Tracker, together with the more fine-grained Inner Tracker, will perform the charge particle tracking behind the vertex region with a system of nine tracking stations. The tracking system, consisting of the Inner Tracker and Outer Tracker, must perform the following tasks: find charge particle tracks in the region between the vertex detector and the calorimeters and measure the particle momenta, provide precise measurements of the direction of track segments in the two RICH detectors, and link measurements in the vertex detector with the calorimeters and the muon detector.
Following further questions and discussions, the referees will make a full report on the Outer Tracker TDR at the next meeting of the LHCC.
The LHCb Collaboration is in the process of re-optimising the detector by re-examining its material budget. The current number of nine tracking stations has resulted from dropping the station in the middle of the magnet and one just behind the RICH-2, as it was shown to not affect the tracking performance. While maintaining the technology and design of the individual tracking detectors, re-optimisation of the remaining nine tracking stations is being studied in order to reduce further the amount of material in front of RICH-2. The re-optimisation also includes reducing the material in the RICH-1 mirrors and the Vertex Locator RF shielding. The Collaboration will submit to the LHCC in the autumn 2002 a detailed document reporting on the design and performance of the re-optimised detector. As a result, submission of the Inner Detector and Trigger TDRs are now delayed by one year. The LHCC considers that the delay is not critical.
The referees also provided updates to the status of the sub-systems and reviewed the TDR milestones.
5. COST REVIEW OF THE CMS LEVEL-1 TRIGGER TDR AND THE LHCb VERTEX
LOCATOR AND MUON SYSTEM TDRs
W. Bartel reported on the cost evaluation of the CMS Level-1 Trigger TDR and the LHCb Vertex Locator and Muon System TDRs, analyzed together with S. Quinton and D. Ressing.
He reported that the costing of the CMS Level-1 Trigger TDR is considered sound. The cost estimates are based on quotes from industry and from prototype work. They include spare parts for the electronics and also an adequate provision of manpower.
In addition, the costing of the LHCb Vertex Locator and Muon System TDRs is also considered to be sound. The costing includes spare parts for the electronics and Si sensors in the case of the Vertex Locator and is based on quotes from industry and prototype work as well as payments for similar devices by the HERA-B experiment at DESY.
6. REPORT FROM CORE ON ATLAS AND CMS COMPLETION COSTS
On behalf of the LHCC CORE Committee, W. Bartel reported on the ATLAS and CMS costs to completion.
ATLAS is well-advanced in the construction of the detector and nearly 60% of the total budget has been either spent or is firmly committed. Similarly, CMS has either spent or firmly committed 55% of the total budget. Although both experiments are experiencing cost increases as well as a deficit in their funding, the LHCC considers that both ATLAS and CMS are following strict budgetary control and should be commended. The conclusions of the review will be presented to the October sessions of the Resource Review Boards (RRBs).
It was noted that the costs for commissioning and integration (C&I) and maintenance and operation (M&O) are preliminary and that they are currently under discussion by a separate group. Moreover, the computing costs were not included in the present evaluation and the costing for the magnets was reviewed by the LHCC Magnet Advisory Group (MAG).
7. REPORT FROM THE LHCC MAGNET ADVISORY GROUP
T. Taylor presented a report from the LHCC Magnet Advisory Group (MAG) review meeting held on 1 and 2 October 2001. A written report will be available shortly.
The ALICE and the LHCb dipole magnets are both on track and the reported costs are within the budget estimates. For both magnets, orders have been placed for the conductor, and the coil and yoke manufacture.
The MAG is fully satisfied with the progress on the CMS yoke and end-caps as exhibited by the well-advanced state of the assembly on the surface at the CMS area at Point 5. Substantial progress was reported on the conductor and coil, highlighted by the successful demonstration of the continuous welding process. The MAG commends the Collaboration for exercising strict budgetary control, as the magnet project was shown to be almost within budget with about 85% of the costs having been already committed.
Concerning ATLAS, the MAG noted the successful testing of the B0 prototype coil of the barrel toroid magnets and noted the substantial progress on these magnets, which were a matter of severe concern in 2000. A technically sound solution has now been identified, albeit at an increased expense. The MAG also noted the sound progress on the central solenoid magnet and congratulates the group for completing the first spectrometer magnet for the LHC experiments. However, the end-cap toroids are now late and the accrued delays are becoming critical. ATLAS is discussing with the commercial supplier of the cold mass ways to ensure the delivery of this time-critical piece. Although the cost of the ATLAS magnets has increased from the 1996 estimates, strict cost management has been exercised by ATLAS, thus minimizing the cost overrun, which could otherwise have been very substantial.
8. TEST BEAMS
M. Hauschild presented a status report on the SPS and PS Fixed Target Programmes.
He also showed the draft machine schedules for 2002 as presented to the Research Board. The PS East Hall physics programme is scheduled to run for 198 days, from 27 March to 4 November, while 133 days are foreseen for the SPS proton run, from 18 April to 30 August, and 38 days for the SPS Pb-ion run from 25 September to 4 November. The schedule includes a number of machine development periods at both the PS and SPS and also about a two week stop to both machines at the end of August. In spite of this, the total number of running days is comparable to that achieved in recent years since some time can be recovered. However, as reported at the recent session of the Research Board, the CERN Management is considering ways of recuperating for physics the two week PS shutdown period.
Finally, he showed the preliminary requirements of the LHC experiments for test beam time in the coming years. The Research Director for Collider Programmes stressed that the experiments will have to submit further documentation in the future to the LHCC and the SPS/PS Coordinator justifying their intended future test beam programmes. The LHCC urges all collaborations to make every effort to be realistic in their requests and to allow sufficient advance warning in case of difficulties that may affect their ability to utilize assigned beam time.
9. LHCb VERTEX LOCATOR TECHNICAL DESIGN REPORT
The LHCC has completed its scientific, technical, and cost evaluation of the LHCb Vertex Locator TDR submitted in May 2001. The Committee was impressed by the quality of the work presented in the TDR and congratulates the Collaboration. The technology and design of the Vertex Locator are well-suited for reconstructing b- and c-hadron decay vertices, for separating these decay vertices from the production vertex, for accurately measuring decay lengths, and for measuring the impact parameters of particles used to tag their flavour. The detector is thus adequate to achieve the physics goals stated in the LHCb Technical Proposal.
The Committee has no major concerns. An ancillary document (LHCC 2001-028) contains items of lesser concern as well as a list of agreed milestones for monitoring the progress of the project. The LHCC review was not an engineering review, although some engineering aspects of the project were presented and discussed with the referees. The LHCC recommends that LHCb follows the established practice of conducting independent reviews of the engineering designs. Written reports should be made available to the LHCC through its referees.
The LHCC notes that the LHCb Collaboration is undertaking an extensive re-optimisation of the lay-out of the LHCb tracking system, which may have consequences for the Vertex Locator. Any design changes will need to be presented to the LHCC before construction of the Vertex Locator commences.
The LHCC recommends general approval of the LHCb Vertex Locator Technical Design Report. The LHCC considers the schedule given in the TDR and the list of milestones in the ancillary document to be reasonable. They will be used by the Committee to measure and regulate the future progress of the project.
10. LHCb MUON SYSTEM TECHNICAL DESIGN REPORT
The LHCC has completed its scientific, technical, and cost evaluation of the LHCb Muon System TDR submitted in May 2001. The Committee was impressed by the quality of the work presented in the TDR and congratulates the Collaboration. The technology and design of the Muon System are well-suited for triggering on muons from b-hadron decays, by identifying muons and linking tracks in the muon system with the correct tracks in the tracking system. The detector is thus adequate to achieve the physics goals stated in the LHCb Technical Proposal.
The Committee has no major concerns. An ancillary document (LHCC 2001-029) contains items of lesser concern as well as a list of agreed milestones for monitoring the progress of the project. The LHCC review was not an engineering review, although some engineering aspects of the project were presented and discussed with the referees. The LHCC recommends that LHCb follows the established practice of conducting an independent review of the engineering design. Written reports should be made available to the LHCC through its referees.
The LHCC notes that the LHCb Collaboration is undertaking an extensive re-optimisation of the lay-out of the LHCb tracking system and expects the impact of this on the muon identification, trigger and measurement to be presented to the Committee.
The LHCC recommends general approval of the LHCb Muon System Technical Design Report. The LHCC considers the schedule given in the TDR and the list of milestones in the ancillary document to be reasonable. They will be used by the Committee to measure and regulate the future progress of the project.
11. CMS COMPREHENSIVE REVIEW
Since the first of the CMS Comprehensive Reviews in October 2000, the CMS Collaboration has made very significant progress towards the realisation of an experimental set-up ready to record proton-proton collisions at the LHC in April 2006.
It is realistic to expect CMS to install an initial working detector suitable for the first collisions of the LHC pilot run starting in April 2006 and for the physics run starting in August 2006, although the completion of the detector installation can be foreseen beyond this date. The LHCC considers that the CMS schedule to achieve thisis challenging. The LHCC notes that additional resources, both in terms of money and manpower, would aid in accelerating the current CMS schedule, and thereby would ensure a timely completion of the initial detector in 2006.
In the event that additional funding is not available to ensure completion of CMS in 2006 as described in the Technical Design Reports, the installation of some components of the Tracker, HCAL, Muon System, and TRIDAS will be deferred in a staging plan which is presently being prepared. Staging of one or both of the ECAL end-caps is also being considered. In these circumstances, and following a shutdown of a few months in 2007 after the end of the first physics run, the CMS detector as described in the approved Technical Design Reports would be complete.
The proposed staging plan for the experiment is aimed at having a small adverse impact on the Higgs and SUSY sensitivity at a luminosity of order 1033 cm-2 s-1. However, the possible omission of the ECAL end-caps would lead to a major deficiency in the low-mass Higgs search in the favoured H->gg channel. The Committee strongly supports the Collaboration in its efforts to re-optimise the funding profile and to secure additional funding so as not to stage the ECAL end-caps. The LHCC wishes to stress to the CMS Collaboration the importance of having full coverage in acceptance with the ECAL from the start of the first LHC physics run. One of the primary strengths that CMS brings to LHC physics is the high quality of its EM calorimetry, and the excellent sensitivity that it has to the low-mass H->gg decay channel. It would be highly inappropriate if this strength was not exploited from the beginning of any discovery window for Higgs that is likely in 2006.
The second annual LHCC Comprehensive Review of CMS took place on 1-2 October 2001. The LHCC referees addressed the following areas: Inner Detector, Calorimetry, Muon Spectrometer, Trigger/DAQ/DCS, Physics Studies, Computing, Test Beams and the topics of Management, Technical Coordination, Integration, Schedules and Costs.
The principal 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 forthcoming sessions of the LHCC prior to the next CMS Comprehensive Review one year hence.
Provisional Dates for 2002:
The LHCC received the following documents