LARGE HADRON COLLIDER COMMITTEE
Minutes of the forty-third meeting held on
Wednesday and Thursday, 20-21 October 1999
1. Status of the LHC project: L. Maiani
2. Status of the LHC machine: L. R. Evans
3. ALICE PMD TDR (LHCC 99-32 / ALICE TDR 6): Y.
Present: B. Adeva, G. Altarelli, J.
Carr, R. Cashmore, D. Cassel, J. Dainton, J. Engelen (Chairman),
A. Ereditato, B. Foster, M. Kasemann, H. Kolanoski, G. Goggi, J. Lee-Franzini, B. Löhr,
J. May, K. Potter, A. Read, G. Rolandi, A. Rostovtsev, P. Roudeau, T. Ruf, H. Schellman,
P. Sharp, E. Tsesmelis (Secretary), G. Zech.
Apologies: W. Bartel, M. Delfino, R. Kephart, M.
The Chairman welcomed the new members of the Committee, and thanked the retiring members for their vital role in defining the LHC experimental programme.
The minutes of the forty-second LHCC meeting (LHCC 99-30 / LHCC 42) were approved without modification.
2. REPORT FROM THE ALICE REFEREES
The Committee heard a report from the ALICE referees, concentrating on the review of the Technical Design Report for the Dimuon Forward Spectrometer, which was performed with P. Borgeaud and U. Heinz as consultants. The main physics goal of this spectrometer is to perform a measurement of the Y and U family production yields via their decay into muon pairs. These measurements will provide information on the onset of a phase transition of hadronic matter in a critical region of energy density and temperature.
The referees also reported on their preliminary reactions to the Technical Design Report for the Photon Multiplicity Detector. The detector will measure the multiplicity and spatial distribution of photons and will aid in the estimation of the transverse electromagnetic energy, all on an event-by-event basis. These measurements will facilitate the study of chiral symmetry restoration, of the deconfinement transition and of matter under extreme conditions. Following further questions and discussions, the referees will make a full report at the next meeting of the LHCC.
The referees also reviewed the schedule for the remaining ALICE Technical Design Reports and reported on the project milestones of the sub-detectors, emphasizing those for the HMPID. Depending on the final lay-out of ALICE, the HMPID mechanics will be re-designed to adapt to the final space frame for the overall ALICE detector. It is thus expected that a revised baseline schedule for the HMPID will be required but it is foreseen to have minimal influence on the completion of the project.
Test beams with the PPC show an excellent time resolution and rate capability for all devices tested. Further studies to understand the operation of these chambers are under way.
3. REPORT FROM THE ATLAS REFEREES
The Committee heard a report from the ATLAS referees. An updated list of milestones was presented and the progress of the various projects was reviewed.
The referees also reported on the status of the Module-0 detectors for the muon system, covering the progress in the MDT, RPC, CSC and TGC projects. Module-0 and series production of chambers is now starting and the instigated quality assurance and control procedures will enable the early correction of any detected problems. Apart from the MDTs, no other muon system is on the critical path. A more realistic planning for the MDTs is expected after results from all Module-0 detectors are available and production of the chambers has commenced.
The referees also reviewed the LVL1 trigger status. Good progress was reported on a number of issues, including the architecture and algorithms for the muon and calorimeter triggers in the barrel and end-cap, latency envelopes, the interface between the LVL1 and LVL2 trigger levels and the trigger hardware. Several solutions to improve the LVL1 muon trigger robustness against the 100 MeV background of charged particles produced by neutrals have been included in the trigger design.
4. REPORT FROM THE CMS REFEREES
The Committee heard a report from the CMS referees. The current status of the various milestones was reviewed, including changes relative to estimates of one year ago.
The referees also reported on the tracker. An extensive MSGC test programme is presently in progress at PSI. The alternative option of an all-silicon tracker is being studied in parallel and is deemed to be well-advanced. Results from the MSGC test programme and from the study of the all-silicon tracker will be available for a decision to be made by CMS in December 1999. The choice of the latter would require the submission of an addendum to the CMS Tracker TDR early in 2000 showing the viability of the project.
The referees also reviewed the CMS alignment systems. The aim of the systems is to monitor the position of the muon chambers and tracker separately and with respect to each other. Owing to space restrictions, a simplified alignment system for the tracker has been proposed. A prototype version of the CMS Link Alignment System has been installed in an experimental area of the ISR and measurements are in progress.
Studies on the operating characteristics of the I-beams of the muon barrel Drift Tubes are in progress. These studies do not delay the full-scale pre-production prototype but a final resolution is required before mass-production of the I-beams commences.
5. REPORT FROM THE LHCb REFEREES
The Committee heard a report from the LHCb referees following their recent overall review of the experiment. In general, LHCb is on schedule and seems able to build the proposed experiment. The submission of TDRs is about to start.
The progress on technologies for the RICH photodetectors was reported. The two options are Hybrid Photodiodes (HPDs) and photomultipliers (PMTs), with no commercial device being available to satisfy the requirements of the RICH. A panel has been nominated to prepare a recommendation - based on performance, costs, resources and risk ó which will be submitted to the LHCb Technical Board for a final decision to be taken by the collaboration in December 1999.
The referees also reported on the status of the calorimeter, including the milestones leading up to the submission of the TDR. The first combined test beam of the preshower, ECAL, HCAL and electronics was performed in October 1999.
Good progress was reported on the tracking detectors ó Vertex Locator (VELO), the Inner and Outer Trackers and the muon chambers ó and no major concerns were expressed. Irradiation tests of VELO provided encouraging results and further studies are in progress. Tests of MSGCs for the Inner Tracker are continuing and an option based on silicon is being investigated. Comparison of straw tubes and honeycomb chambers for the Outer Tracker is in progress. Work on the muon chambers has concentrated on background studies, design of the lay-out and beam tests, all leading up to the technology choice in January 2000.
LHCb has made substantial progress on the trigger, highlighted by advances in the choice of LVL0 technologies. Work is under way on assessing various DAQ architectures and on addressing the LHCb front-end electronics. Physics simulations have explored the sensitivity of the trigger to various structure function parameterizations.
The referees also reported on the design of the dipole spectrometer magnet. In the LHCb Technical Proposal, the magnet was superconducting but the collaboration investigated in parallel a version using resistive coils. LHCb has produced a design concept for such a resistive magnet which is well-adapted to the experiment. The Magnet Advisory Group (MAG) fully endorses this design concept, as detailed in the document LHCC 99-35. The LHCC takes note of the recommendation from MAG.
6. ALICE DIMUON FORWARD SPECTROMETER TECHNICAL DESIGN REPORT
The LHCC has completed its scientific, technical, and initial cost evaluation of the ALICE Dimuon Forward Spectrometer TDR submitted in August 1999. The Committee was impressed by the quality of the work and congratulates the collaboration. The TDR describes a powerful spectrometer for the measurement of forward dimuons in ALICE.
The spectrometer design and the tracking technologies proposed are adequate to perform a detailed study of heavy quarkonia production in conjunction with other detectors in ALICE, in particular those measuring centrality.
The Committee has no major concerns; however, an ancillary document (LHCC 99-37) 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. It is recommended that ALICE conducts an independent review of the engineering design. Written reports should be made available to the LHCC through its referees.
The LHCC recommends general approval of the ALICE Dimuon Forward Spectrometer Technical Design Report, pending a final cost evaluation. The LHCC considers the schedule given in the TDR and the revised 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.
7. REPORT FROM THE TOTEM REFEREES
The Committee heard a report from the TOTEM referees, concentrating on the integration of TOTEM into CMS and the LHC machine lay-out. The Committee takes note that the present LHC machine lay-out is compatible with the TOTEM total cross-section measurement and can provide the necessary high-b optics. In addition, the Committee takes note of the agreement between CMS and TOTEM on the boundary conditions for the integration of TOTEM into CMS.
The Committee also discussed the TOTEM Technical Proposal submitted in March 1999. The Committee is convinced that the TOTEM Technical Proposal can lead to a successful total cross-section measurement. Accordingly, with the aim of TOTEM measuring the total cross-section and providing the CMS luminosity calibration, the LHCC recommends approval of the TOTEM Technical Proposal (CERN / LHCC 99-7 / P5) leading to such a measurement.
The Committee encourages TOTEM, in consultation with CMS, to continue developing the experimental design of their detectors in order to prepare a Technical Design Report. The TDR should describe a viable detector for the measurement of the total cross-section and for the CMS luminosity calibration. The design should be consistent with the existing agreement with CMS and should satisfy the criteria for the integration of TOTEM into the LHC machine lay-out.
8. REPORT FROM THE LHCC ELECTRONICS BOARD
P. Sharp reported on the work of the LEB, concentrating on the very successful Fifth Workshop on Electronics for LHC Experiments held at Snowmass on 20-25 September 1999. The main issues consisted of identifying problems and moving towards common solutions for all LHC experiments. It was particularly stressed that all the electronics in the LHC caverns are at risk and that a common project to co-ordinate the selection, evaluation and procurement of COTS (Commercial-Of-The-Shelf) components for the LHC is recommended by the LEB. Finally, P. Sharp argued that the LEB, by monitoring and reviewing the electronics projects, has a crucial role to play during the construction period of the experiments.
9. REPORT FROM THE STANDARD MODEL WORKSHOP
G. Altarelli presented the programme of the well-attended and very successful Workshop on Standard Model Physics at the LHC held at CERN on 14-15 October 1999. The transparencies are available on the World-Wide Web and a CERN Yellow Report is in preparation. He summarized current developments and activities, covering topics in QCD, electroweak physics, top quark physics and B physics (both b- production and decay). Particular attention was given to preparing a complete review of these topics, including the potential for experimental measurements and prospects for theoretical and experimental progress in the near future. The workshop also documented the current understanding of the benchmark cross-sections, theoretical and experimental systematic uncertainties, and also recorded the status of the available Monte Carlo tools.
10. TEST BEAMS
T. Ruf showed the updated schedules of the 1999 SPS and PS Fixed Target Programmes. The SPS proton run for this year has been completed and preparations are under way for the heavy-ion run.
He also showed the draft machine schedules of the PS and SPS for next year. Twenty-nine weeks are foreseen for the former, from 10/4 to 26/11, while 19 weeks are scheduled for the SPS proton run from 2/5 to 10/9, to be followed by 5 weeks and 4 days for heavy-ions at the SPS from 25/9 to 3/11. Based on these machine schedules, draft schedules of the physics programmes are in preparation for discussion with the users.
11. ANY OTHER BUSINESS
The Director of Research for Collider Programmes announced that a CERN computing review will take place during the course of next year. The aim of the exercise is to review the future computing requirements for the LHC, the accompanying software for the LHC experiments and the resources and management structure which needs to be put in place. The process will be carried-out by three panels.
The Chairman informed the Committee that a change to the reviewing procedure of the LHCC is being discussed, with the aim of introducing periodic reviews of the experiments in their entirety and of facilitating the exchange of knowledge and experience between the referee teams.
The Secretary informed the LHCC of the availability from the IT Division of a large-scale computer system ó the Meiko CS-2 system ó which under CERN Financial Rules (Rule 13) may be given to educational and scientific research institutes, to museums and to public bodies in Member States. Any such body interested in receiving this equipment should contact Lennart Jirden of the SPL Logistics Group. Additional information may be found at http://wwwinfo.cern.ch/pdp/pa/hepix96/node4.html.
Following the changes of the LHCC membership, the referees are now as follows:
ALICE: B. Adeva, A. Ereditato (Co-ordinator), G. Rolandi, G. Zech
ATLAS: M. Kasemann, R. Kephart, (Co-ordinator), J. Lee-Franzini, P. Roudeau
CMS: J. Carr (Co-ordinator), J. Dainton, S. Komamiya, B. Löhr
LHCb: D. Cassel (Co-ordinator), A. Rostovtsev, H. Schellman
MOEDAL: P. Roudeau
TOTEM: G. Rolandi, H. Schellman (Co-ordinator)
13. DATES FOR 2000 MEETINGS
The LHCC received the following documents
* Restricted circulation only.