CERN/LHCC 2001-020
LHCC 53
15 August 2001
 

LARGE HADRON COLLIDER COMMITTEE

Minutes of the fifty-third meeting held on
Wednesday and Thursday, 4-5 July 2001

OPEN SESSION:
 
1.LHCb Vertex Locator Technical Design Report: T. Ruf, J. van den Brand

2.LHCb Muon System Technical Design Report: B. Schmidt, G. Carboni

CLOSED SESSION: Present: W. Bartel*, R. Cashmore, J. Dainton, M. Delfino*, J. Engelen (Chairman), A. Ereditato, J.-J. Gomez-Cadenas, M. Hauschild,
H. Hoffmann*, Y. Karyotakis, J. Lee-Franzini, B. Löhr, M. Mangano, J. May*, J. Nash, K. Potter, P. Roudeau, D. Schlatter,
K. Tokushuku, E. Tsesmelis (Secretary), G. Zech. *) Part timeApologies: D. Cassel, P. Lebrun, L. Maiani, J. Panman, H. Schellman.
1.       INTRODUCTION The minutes of the fifty-second LHCC meeting (LHCC 2001-016 / LHCC 52) were approved with the following modification: in point 9 (discussion on the LHC Computing Review), the third and fourth sentences should be replaced by: "The LHCC considers that the LHC Computing Review, which was held under the chairmanship of S. Bethke, has set out a sound model for the future LHC Computing. The LHCC also endorses the identification of a potential lack of resources ó hardware, infrastructure and related manpower ó while noting the limited maturity of the current planning and resource estimates for the production of the software, the development and support of simulation packages and the support and future evolution of analysis tools."

The Research Director for Collider Programmes reported on issues being currently considered to appraise the status of the LHC programme. The completion plans and the resources required to realise the experiments will be discussed at the next Resource Review Boards (RRBs) in October. As part of the regular reports from the LHCC to the RRBs, which provide a summary of the principal deliberations of the Committee, the LHCC is asked to provide an evaluation of the soundness and feasibility of these plans. Moreover, the LHCC `COREí group will appraise the costs required to complete the experiments. In addition, the RRBs are evaluating the required funds to cover the maintenance and operation of the LHC experiments. The LHC computing resources will be addressed in the context of the LHC Computing Grid Project. Together with the principal contracts for the LHC Machine, this information will be presented subsequently to the CERN Council, thus providing an evaluation of the whole LHC programme.

2.       REPORT FROM THE ALICE REFEREES The LHCC heard a report from the ALICE referees, covering the overall status, the milestones, the new technical coordination team and detector and integration issues.

The referees also reported on the interest of US groups to participate in the ALICE programme. The groups intend to submit a proposal to the Department of Energy for funding in view of this participation, emphasizing the uniqueness of the LHC heavy-ion programme. The proposal will be based on building an additional electromagnetic calorimeter to further the study of high-PT probes and jet quenching.

The referees also presented a progress report on the Time-of-Flight detector. The Committee noted the impressive R&D results on the detector strip performance and on the prototype of the front-end amplifier card. However, a number of issues concerning both the detector and electronics must still go through the R&D phase. An issue which needs urgent resolution is the choice between discrete front-end electronics versus ASIC. The decision would be taken by ALICE in the coming weeks and will be communicated to the LHCC. The Committee encourages ALICE to make a single choice as the baseline and to proceed with that, leaving the other option as a back-up. Due to the delays in completing the R&D phase, ALICE requests that the Addendum Technical Design Report be submitted later than originally agreed, namely in March 2002. The LHCC considers that the submission would now come late and encourages ALICE to advance it as much as possible.

3.       REPORT FROM THE CMS REFEREES The Committee heard a report from the CMS referees. The referees reported on the updated CMS milestones. The list of milestones has been updated in order to bring the overall CMS schedule in line with the new LHC Machine schedule. The list of milestones in its final form will be scrutinized in the upcoming CMS Comprehensive Review scheduled for October.4.       REPORT FROM THE LHCb REFEREES The LHCC heard a report from the LHCb referees, concentrating on the preliminary reactions to the Vertex Locator (VELO) and Muon System Technical Design Reports.

The VELO consists of a series of silicon stations placed along the beam direction at a radial distance from the beam that is smaller than the aperture required by the LHC during injection and must therefore be retractable. The detector must 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 consists of five stations using RPCs in the regions where the expected rate is relatively low and MWPCs for all other regions except for the innermost part of the first station where the expected rates will be highest. In this latter part a detector technology has still to be selected. Various technologies such as asymmetric MWPCs or triple-GEM detectors are under investigation. 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.

Following further questions and discussions, the referees will make a full report on both of these Technical Design Reports at the next meeting of the LHCC.

5.       DISCUSSION ON THE LHC COMPUTING REVIEW The LHCC, in its role of reviewing the programme to do physics at the LHC, is also considering the requirements for the associated computing. The proposal for building the LHC computing environment, known as the LHC Computing Grid Project, involves a two-phased approach covering the years 2001-2007, as outlined in document CERN/2379/ Rev. (3 July 2001). The first phase from 2001-2004 consists of developing the model and building prototypes, work which will lead to a final proposal for a distributed Grid system and its coordinated deployment and exploitation. The second phase consists of the installation and operation of this full world-wide initial production Grid system in the years 2005-2007.

A formal project structure will be put in place to ensure the achievement of the required functionality and performance of the overall system. The LHCC underlines that the composition of the project structure should be in the full interest of the LHC programme, with the experiments being intimately involved.

The LHCC considers that this plan, which includes the required additional resources both at CERN and in the Member States and Non Member States, is reasonable and endorses it as the next step forward in proceeding with the LHC Computing.

6.       TEST BEAMS M. Hauschild presented a status report on the SPS and PS Fixed Target Programmes. He reported that the PS Complex is running well and that the SPS is on schedule in its commissioning phase after its longest shutdown in about 20 years. He also discussed the HARP proposal to run in 2002 with both proton and He++ beams. This would delay the transfer of the T9 beamline currently used by HARP to LHCb and running with He++ would exclude the parallel running of the other beamlines in the PS East Hall. In its May 2001 session, the SPSC did not recommend approval of the HARP proposal, as the Committee did not deem sufficiently scientifically interesting the collection of He++ data on Carbon/Oxygen at the low momenta available at the PS East Hall. Finally, he mentioned that a Pb heavy-ion run will be scheduled for the end of 2002, its duration being currently under discussion.7.       ATLAS COMPREHENSIVE REVIEW Since the first of the ATLAS Comprehensive Reviews in July 2000, the ATLAS Collaboration has made very significant progress towards the realization of an experimental set-up ready to record proton-proton collisions at the LHC in April 2006. In particular, construction of the majority of the final components has either started or is imminent.

The design and tests of the front-end electronics have in general been successfully completed, although in some cases the transfer of these designs into radiation-hard technologies has not yet been achieved. Back-up solutions have, however, been identified and are being implemented.

It is realistic to expect ATLAS to install an initial working detector for the first collisions of the LHC pilot run starting in April 2006 and for the physics run starting in August 2006, although detector installation can be foreseen beyond this date.

However, the LHCC considers that the ATLAS plan to have commissioned an initial working detector for first collisions in April 2006 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 schedules of the Barrel Toroid Magnet, the TRT End-cap A, the LAr EM Barrel, the LAr End-cap A, and the Muon Drift Tube chambers are considered to be critical. The LHCC observes that additional resources, both in terms of money and manpower, would aid in accelerating the current ATLAS schedule, thereby allowing a timely completion of the initial detector in 2006.

A detailed scenario to complete the initial working detector by August 2006 is being worked out by ATLAS and will be submitted to the LHCC at the end of October. The ATLAS Collaboration must develop such a detailed scenario, which should in particular address the critical schedule issues above.

Detector elements not installed by August 2006 will be staged. The staging plan consists of deferring installation of some components of the Inner Detector, the Calorimetry, the Muon Instrumentation, the High-level Trigger and DAQ and the radiation shielding. Their installation in a shutdown of a few months in 2007 after the completion of the first physics run, while requiring additional resources, would complete the ATLAS detector as described in the approved Technical Design Reports.

The LHCC considers that a completed initial working detector, in time for the first physics run in August 2006, should allow the experiment to address satisfactorily the physics searches for Higgs and SUSY at the 10 fb-1 luminosity level. The proposed staging scenarios of the detector have a minimal impact on the searches at a luminosity of order 1033 cm-2 s-1. The staged components would, however, need to be installed for the higher luminosity running.

The second of the LHCC Comprehensive Reviews of ATLAS took place on 2-3 July 2001. The LHCC referees addressed the following areas: Inner Detector, Calorimetery, Muon Spectrometer, Trigger/DAQ/DCS, Physics Studies, Computing, and the topics of Management, Technical Coordination, Integration, Schedules and Costs.

The principle conclusions and concerns of the LHCC are summarized 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.

8.       DATES FOR LHCC MEETINGS
2001:
3-4 October
21-22 November
Provisional Dates for 2002:
23-24 January
13-14 March
15-16 May
  3-  4 July
  2-  3 October
27-28 November


The LHCC received the following documents

LHCC Secretariat: Janet Grant (Bldg. 14/4-022), Tel. 73424; janet.grant@cern.ch