LARGE HADRON COLLIDER COMMITTEE
Minutes of the forty-fifth meeting held on
Wednesday and Thursday, 8-9 March 2000
2. CMS status report: M. Della Negra
3. Addendum to CMS Tracker Technical Design Report (LHCC
2000-016/CMS TDR 5 Add. 1):
*) Part time
Apologies: G. Goggi, M. Kasemann.
The Chairman welcomed K. Tokushuku, a new member of the
Committee, and B. Lofstedt, a consultant for the ALICE Time-of-Flight
The Chairman informed the LHCC that the Research Board, at its 145th Meeting on 17 February 2000, approved the ALICE TDR on their Photon Multiplicity Detector under the LHCC formulation which allows the Committee to monitor future progress through the implementation of the schedules and milestones listed in the ancillary document. Moreover, the Research Board took note of the LHCC recommendations concerning the proposed further programmes for RD42 and RD39.
The minutes of the forty-fourth LHCC meeting (LHCC 2000-006/LHCC 44) 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 TDR for the Time Projection Chamber (TPC). The TPC is the main tracking detector of the central barrel and together with the Inner Tracking System (ITS), Transition Radiation Detector (TRD) and Time-of-Flight (TOF) will provide the charged particle momentum measurement, particle identification, vertex determination, two-track separation and dE/dx resolution for studies of hadron and lepton signals.
The referees also reported on their preliminary reactions to the TDR for the Time-of-Flight (TOF) detector, with B. Lofstedt as consultant for the electronics. The design of the TOF array is based on gaseous multi-gap resistive plate chambers (MRPC). Particle identification over a large part of the phase space and for various particles is an important design feature. The TOF rapidity acceptance has to be large enough to cover the full central acceptance of ALICE and should cover the hadron momentum range from about 0.5 GeV/c to about 2.5 GeV/c, complementing the HMPID which is specialized for higher momenta. Following further questions and discussions, the referees will make a full report at the next meeting of the LHCC.
The referees also reviewed project milestones of the sub-detectors, emphasizing those for the Silicon Pixel and the Dimuon Forward Spectrometer. The proposal to modify the design and schedule for the third tracking station of the latter may have implications on the overall detector performance. Following the submission of a written document by ALICE and further discussion, the referees will report again at the next meeting of the LHCC.
The referees also presented the document detailing the ALICE organization (LHCC 2000-004). The Committee considers the proposed organization scheme to be reasonable.
3. ALICE PMD AND TPC COST REVIEW
W. Bartel reported on the cost evaluation of the ALICE Photon Multiplicity Detector and Time Projection Chamber TDRs. The PMD represents a relatively small sub-system of the ALICE detector. Its costing is considered to be reasonable and the required manpower is assumed to be available. For the TPC, considered as a major project, the cost estimates have a firm basis in industrial offers and in the experience gained during the prototype work. The costing is also considered to be reasonable and it fits into the overall cost of the experiment. However, some concern was expressed for the available manpower for the TPC general systems aspects. The LHCC endorses these conclusions.
4. REPORT FROM THE ATLAS REFEREES
The Committee heard a report from the ATLAS referees, including an overview of the project schedules and milestones. A revision of the ATLAS master schedule will be available in the spring and will include corrective actions already taken in order to cope with the currently-reported delays in some components.
The referees also discussed progress of various sub-systems. The barrel toroids are on the critical path and solutions are being sought to rectify this. Several choices for the mechanics of the pixel detector were made in 1999 according to schedule. The SCT detector design is finalized, the experimental programme to qualify companies is completed and detector orders have been placed. Prototypes of radiation-hard front-end electronics have been demonstrated to work and are currently under detailed evaluation before a vendor is chosen in the coming weeks. Straw production for the TRT is now in progress in Russia. The LAr calorimetry has entered the production phase. Some technical issues with industries have however affected the schedule, resulting in the LAr EM barrel calorimeter now being on the critical path.
5. REPORT FROM THE CMS REFEREES
The Committee heard a report from the CMS referees, concentrating on the preliminary reactions to the Addendum to the CMS Tracker TDR. The Addendum describes a tracker based on the chosen all-silicon option. The choice leads to a uniform technology and it is considered that such a tracker will be simpler in many systems aspects. Moreover, the reduction in costs of silicon and the associated electronics appears to make such a choice financially feasible. Following further questions and discussions, the referees will make a full report at the next meeting of the LHCC.
The referees also presented the list of updated milestones. The referees consider that the updated schedule does not provide sufficient time for the installation, integration and testing of the experiment in the underground area. To do so by mid-2005 would require considerable extra investments, mainly in manpower.
The referees also discussed progress in the Level-1 trigger and ECAL. The TDR for the former is expected to be submitted in the autumn. CMS performed an internal review of the ECAL. Additional investments, particularly in ovens for crystal growing in China, are required in order for the ECAL to be ready in mid-2005. The Committee asks for an updated schedule by the next meeting of the LHCC.
6. REPORT FROM THE LHCC ELECTRONICS BOARD
P. Sharp reported on the work of the LEB, covering a number of topics discussed at the January meeting. Further details can be found in the LEB minutes. The LEB reviewed the RD12 project addressing Timing, Trigger and Control (TTC) issues. Impressive progress was reported. The project has satisfied the requirements of the LHC experiments and it is likely that the system will be adopted. The LEB recommends that work should continue in the form of a common project and that support should be provided for the duration of the LHC.
The LEB reviewed the RD48 project (ROSE) on radiation-hard silicon. The collaboration has made very good progress. Good results have been achieved with oxygen diffusion, with which many manufacturers and collaborating institutes agree. The proposed milestones for the project include continuing work with the manufacturers to optimize this process, implementing qualification procedures for test diodes and providing assistance to the LHC experiments to monitor silicon detectors. The collaboration should complete these studies and report at the LEB Workshop in September 2000.
The LEB also reviewed the RD49 project on radiation-tolerant electronics. The collaboration has made exceptional progress, particularly as many examples of successful 0.25 m m CMOS designs for the LHC have been produced. Progress has been reported on COTS (Components off the Shelf) issues but further coordinated activity between the machine and experiments is required. The LEB recommends continuing support for developing the 0.25 m m CMOS technology and for COTS as common projects.
The next workshop on electronics for LHC experiments is planned for Krakow on 11-15 September 2000.
The future functions of the LEB include the promotion of common approaches and solutions, the review of common projects, the review of strategic issues such as maintenance and the assistance to the LHCC in matters pertaining to electronics for the LHC.
7. PROPOSAL FOR NEW REVIEWING PROCEDURE OF THE LHCC
The Chairman presented the proposal of implementing a revised LHCC reviewing procedure. The proposed format will include the introduction of annual comprehensive reviews of each experiment and will be tailored to facilitate the exchange of knowledge and experience between the referee teams. The new procedure is expected to commence with the July session of the LHCC and the detailed schedule is under discussion.
8. ALICE TIME PROJECTION CHAMBER TECHNICAL DESIGN REPORT
The LHCC has completed its scientific, technical, and cost evaluation of the ALICE Time Projection Chamber TDR submitted in January 2000. The Committee was impressed by the quality of the work presented in the TDR and congratulates the collaboration. The technology and design of the TPC are well-suited for the measurement of charged tracks and adequate to achieve the physics goals stated in the ALICE Technical Proposal.
The Committee has no major concerns. An ancillary document (LHCC 2000-022) 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 Time Projection Chamber 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.
9. REPORT FROM THE LHCb REFEREES
The Committee heard a report from the LHCb referees, including a presentation of the general status and milestones. The collaboration expects to meet the installation milestone of mid-2004. The LHCC referees will continue monitoring the list of project milestones and it will be the focus of their meeting with the collaboration in May.
The referees also reported on the muon system. Progress was reported on the lay-out of the muon system, the impact of the low-energy background on the muon trigger performance and on the muon chambers, and the development of the front-end architecture. The WPC/CPC technology has been adopted for the outer part of station 1 and the inner parts of stations 2 to 5. Additional studies are required before a choice of technology is made for the outer parts of stations 2 to 5 (both WPC/CPC and RPC are viable) and for the inner part of station 1.
The referees also reviewed the progress on the calorimeter and the trigger. For the former, the Committee encourages the collaboration to continue the design of the Scintillator Pad Detector (SPD), leading to the submission of the Calorimeter TDR for LHCC session of October 2000. The TDR for the Level-0 and Level-1 trigger systems is on schedule to be submitted at the end of 2001, while that for the RICH will be submitted for the LHCC meeting of October 2000.
10. REPORT FROM THE MAGNET ADVISORY GROUP
T. Taylor presented a report from the MAG review meeting in February. A written report will be available shortly.
For the CMS solenoid the MAG is fully-satisfied with progress on the barrel and end-cap yokes. Substantial progress was reported for the winding and conductor, although the continuous welding process needs to be demonstrated or be replaced by another technique. No major changes have been made on the winding since last year and its contract has been placed. CMS is not yet held up because of the accident which damaged the new cabling machine used for the conductor for both ATLAS and CMS. The MAG supports the request of CMS to have a bipolar power converter to allow for a controlled and relatively fast partial discharge of the magnet but a stronger justification is desirable.
For ATLAS the MAG considers that the design of the inner solenoid magnet is sound and notes that it will be the first LHC magnet to be ready. The MAG also considers that the design of the end-cap toroids is sound and that they are approximately on schedule. Progress on the B0 and B00 programmes and plans for the barrel toroid procurement were noted: whereas preparations for the testing of the B0 and B00 coils are going well, maximum effort will be needed to complete the barrel toroid engineering on time.
Since the last meeting of the MAG, LHCb has decided to change from the superconducting dipole described in their Technical Proposal to a resistive dipole. The design is sound and is documented in a TDR. The MAG recommends the resistive dipole project to the LHCC. The LHCC concurs with this recommendation.
For ALICE the MAG re-iterates its approval of the choice of a resistive magnet and of its general design. Although this is a large magnet, no fundamental difficulties are foreseen although it was noted that the magnet team requires strengthening.
11. REPORT FROM THE LHC COMPUTING REVIEW
H. Hoffmann presented a status report on the computing review for the LHC. The mandate of the work is to review the computing plans of the LHC experiments and the corresponding preparations in the IT Division with the following aims: to update and identify the requirements for computing facilities, the estimates for the corresponding resources, the software packages, the services to be provided centrally and the activities to be performed at CERN. The review will also assess the analysis software projects and the computing project management structures. The review is guided by a Steering Committee, under which three technical panels operate: the World-wide Analysis / Computing Model panel, the Software Project panel, and the Management and Resources panel. The review's immediate aim is to formulate by June preliminary recommendations for the expected software projects and for the world-wide analysis schemes and to produce preliminary resource-loaded work-plans, with milestones and objectives, reflecting a coherent picture between experiments and CERN IT Division. The results of the review will be the basis for CERN, the collaborating institutes and their funding agencies to formulate Computing Memoranda of Understanding.
12. REPORT FROM THE LHCC COMPUTING BOARD
M. Mazzucato reported on the work of the LCB, covering a number of topics discussed at the September 1999 LCB workshop in Marseille and at the LCB meeting at the end of last year. The LCB workshop and meetings have shown that much progress has been made in all aspects of computing for the LHC. Further details can be found in the LCB minutes.
The above forums reviewed the following issues: architectures of data processing systems, persistency, data analysis and simulation tools and MONARC (Models of Networked Analysis at Regional Centres). Several examples exist of the architectures and their implementation and the various design choices need to be explored and assessed. In view of this, and because of the limitation in scope of existing architectures, it is recommended that the discussion on architecture issues continues in the form of a technical forum. Moreover, an acceptable solution for LHC persistency requirements is not yet available. There is a need to continue evaluating the various solutions and to develop test beds of a reasonable scale. However, in order to proceed with the detailed design, a choice of the underlying technology is awaited. Concerning data analysis tools, the LCB strongly supports the attempt to build an object-oriented PAW. The LCB concluded that GEANT4 works very well and all experiments are working actively with it. Further collaboration in the testing phase between the experiments and the team developing GEANT4 is desirable. Finally, good progress was reported on MONARC and its effort to specify baseline models for distributed computing and regional centers. Phase 2 of the project has been completed and a work-plan for Phase 3 has been produced. The LCB congratulates MONARC for the successful completion of Phase 2.
In future, issues for LHC computing will be addressed by the Steering Committee and the three technical panels of the LHC Computing Review.
13. TEST BEAMS
T. Ruf showed the updated schedules of the physics programmes for 2000 at the PS East Hall, at the SPS and at the Lepton Pre-Injector (LPI) of the PS Complex. He also mentioned that the proposal to reduce the SPS energy as of July from 450 GeV to 400 GeV will be discussed at the next SPSC.
14. ANY OTHER BUSINESS
The Chairman thanked G. Rolandi, who is retiring as member of the LHCC, for his vital role in defining the LHC experimental programme and for co-ordination the LHCC refereeing activities for ALICE.
15. DATES FOR 2000 MEETINGS
Following recent changes of the LHCC membership, the referees are now as follows:
The LHCC received the following documents: