LARGE HADRON COLLIDER COMMITTEE
Minutes of the sixtieth meeting held on
Wednesday and Thursday, 2-3 October 2002
1. ATLAS Physics Programme for the First LHC Run: F. Gianotti / CERN
2. CMS Physics Programme for the First LHC Run: D. Denegri / CEA-Saclay
3. Status Report on the LHC Computing Grid Project: L.
Robertson / CERN
Present: S. Bertolucci, M. Bruzzi*, M. Calvetti
(Chairman), R. Cashmore, A. Ceccucci, J. Dainton, F. Ferroni,
D. Froidevaux*, J.-J. Gomez-Cadenas, M. Hauschild, H. Hoffmann*, M. Jaffre, Y. Karyotakis, B. Löhr,
M. Mangano, P. Messina*, J. Nash, J. Panman, K. Potter, L. Robertson*, W. von Rueden, P. Seyboth,
H. Tiecke, K. Tokushuku, E. Tsesmelis (Secretary), C. Vallée, I. Videau* (representing D.Schlatter),
V. Vuillemin* (representing D. Schlatter)
The report from the ATLAS Comprehensive Review (LHCC 2002-024/LHCC-G-008)
was approved without modification.
He reported on the progress of several of the hardware systems. Good progress was reported on the manufacture of the main dipole magnets. Tests on assembled magnets at CERN have been encouraging with all but one magnet reaching the nominal field. The single rejected magnet has been disassembled and analysis has shown a fault arising from cold welds on the superconducting cable which should not have been present. The problem has been understood and rectified. About 90 further dipoles are in various stages of production in industry. The primary concern is the production of the superconducting cable, but it is believed that recovery from a temporary halt at the producer and the commissioning of a second cabling machine will ameliorate the situation. In the meantime there is enough cable at CERN for about 100 dipole magnets.
Better-than-expected progress was reported on the main quadrupoles. After a successful development phase at CEA-Saclay, the series production of the magnets is now moving to industry.
He also reported on items being discussed at Council. Implementation of the External Review Committeeís proposals is currently in progress. A review of all Work Packages and associated personnel are being made in the Divisions and will be presented to Council in December 2002. The budget for 2003 is considered to be based on a reasonable plan and will also be presented to Council in December 2002.
The October Resource Review Boards will aim to formalize agreements with the funding agencies on the ALICE, ATLAS and CMS costs-to-completion. On-going discussions with funding agencies are continuing to be positive. Funds for the Maintenance and Operation (M&O) costs were agreed in April 2002 and good progress was reported for the ensuing Memoranda of Understanding.
Finally, the Director reported on the successful discussions to release funds for the ATLAS End-cap cryostat and that a new schedule for the low-voltage regulators has been developed by EP Division and ST Microelectronics.
3. REPORT FROM THE ALICE REFEREES
The ALICE Collaboration submitted an updated list of milestones in preliminary form. The referees request that the list is completed by ensuring that (a) the PS East Hall shutdown in 2005 is fully incorporated in the list of milestones, (b) the ready-for-completion dates are specified, and (c) the corresponding full planning is developed. After deliberating, the referees will provide their conclusions at the next meeting of the LHCC.
Progress was reported on the cooling of the ALICE spectrometer magnet. Without requiring work on the welds, the magnet would function at 0.2 and 0.5 T, as required for the ALICE physics programme.
A full report on the Muon Spectrometer and TRD beam tests will be given at the next meeting of the LHCC.
A recent review of the ALICE experimental beam pipe resulted in agreement on the final hardware and the residual pressure is being understood. The installation procedure of the beam pipe is to be detailed.
The first LHCC Installation Review of ALICE is planned for March 2003.
The first of the ATLAS Installation Reviews took place on 24-25 September 2002. The Review Committee addressed the projected schedules and milestones, the required resources to carry-out the installation as well as identifying any potential risks for the installation. In particular, the Committee was charged with reviewing the following issues: details of the planned activities and work packages, origin of the resources, both in terms of money and manpower, critical path items, assessment of risks, survey, alignment and safety.
The Review Committee congratulated ATLAS on their excellent presentation of the formidable challenge of installing the ATLAS experiment at Point 1 of the LHC. The Committee greatly appreciated the work put into the preparation of the review by the ATLAS Technical Coordination and were impressed by the professional approach to finding solutions and the advanced nature of many sub-detectors. Moreover, the Committee felt that the ATLAS Technical Coordination is now a well-organised team with clear lines of responsibility and a convincing methodology.
The Review Committee, however, took note that the installation will be long and difficult and a great deal of work remains to be done. An ancillary document (LHCC 2002-040 / G-018) contains items that will allow the LHCC to follow up outstanding issues and to monitor future progress.
The overall ATLAS installation planning has very few contingencies and this will make the handling of any delays, including possible sub-detector construction delays, very difficult. The introduction of multi-shift working can be used to cope with some delays, but will often require additional resources and re-organisation of the funding. As far as it is possible to determine the present funding arrangements are commensurate with the presented ATLAS installation plan.
The ATLAS Technical Coordination was judged to have this difficult task
well in hand, but there is a considerable risk of schedule delays and an
extraordinary effort will be required continuously to ensure that ATLAS has a
working detector ready for LHC operation in April 2007.
The first of the CMS Installation Reviews took place on 10-11 September 2002. The Review Committee addressed the projected schedules and milestones, the required resources to carry-out the installation as well as identifying any potential risks for the installation. In particular, the Committee was charged with reviewing the following issues: details of the planned activities and work packages, origin of the resources, both in terms of money and manpower, critical path items, assessment of risks, survey, alignment and safety.
The Review Committee congratulated CMS on their excellent presentations and team spirit and was impressed with the well though out approach to the installation of the CMS experiment at Point 5.
The overall impression is that the CMS detector has been engineered from the start to facilitate installation. The concept of large slices, which can be opened without having to disconnect cables and services, gives good access to sub-detectors and hence eases both installation and maintenance.
This modular concept also allows assembly on the surface and lowering in large pieces. As a result of changes in the schedule and the late delivery of underground caverns this concept has been extended to include extensive installation and testing of detectors, which again is seen as very positive. This concept, introduced to cope with delays in the delivery of the underground caverns, also allows some flexibility to handle possible detector delays.
The Review Committee, however, considers that the installation still has a long way to go and much work remains to be done. An ancillary document (LHCC 2002-028 Rev. / G-009) contains items which will allow the LHCC to follow up outstanding issues and to monitor future progress.
The overall planning has very few contingencies and this will make dealing with any possible sub-detector construction delays very difficult. The introduction of multiple shift working can be used to cope with such delays, but will often require additional resources and re-organisation of the C&I funding.
The construction and installation of the CMS experiment has started well.
More work is needed on detector services and cabling particularly for the
inner detectors and on the final stage DAQ commissioning, but there is every
reason to believe that CMS will have a working detector ready for LHC
operation in April 2007.
The conclusions of the study indicate that the different working parameters of the two types of RPCs are for the most part now understood and arise from (a) different normalizations to standard temperature and pressure, (b) the inclusion of SF6 gas in the ATLAS but not in the CMS chambers, and (c) the one-gap (ATLAS) versus two-gap (CMS) configurations.
Ageing tests at the Gamma Irradiation Facility (GIF) are continuing and the Committee underlines the importance of successfully completing these tests. Due account of the requests for ageing tests of several final RPC detectors at the GIF should be taken in the GIF schedule.
Finally, it was concluded that, as in the case of ATLAS, streamers at
voltages moderately above the efficiency plateau knee were not observed in the
Good progress was reported on the LAr, Tile, and Hadronic End-cap Calorimeters. Concerning the Electromagnetic End-cap Calorimeters, problem areas have been encountered with the electrodes, spacers and stacking. Although the final stacking has started, the LHCC considers that it is too early to draw conclusions on any delays in the schedule and will continue monitoring the progress. Moreover, the End-cap C cryostats have exhibited a problem with the spacers between the warm and cold vessels that will require repair. The resulting delay is expected to be recovered and not to affect the overall ATLAS schedule. Significant progress was reported on the negative low voltage regulators, with several hundred samples expected at CERN in November 2002.
The LHCC heard a report on the status of the glass wire-joint problem in the TRT resulting from the reaction of the Xe/CO2/CF4 gas with the wire joint. The TRT group has continued investigating alternative gas mixtures and is now ready to move to a new baseline gas Xe/CO2/O2 coupled with a CF4-based cleaning gas. However, the LHCC noted that the new gas has not yet been completely validated as tests with the final closed gas system and irradiation studies will only be completed in at most two years. Nevertheless, the TRT group has decided to resume construction of the straw tubes while the final validation tests are performed. The Committee expressed its concern as a definitive solution has not yet been confirmed and will continue monitoring the progress closely.
Finally, the LHCC referees received a document on the ATLAS RPC Quality
Following the written submission and the first discussion in the LHCC Closed Session in July 2002 of the LCG proposal for the construction of a prototype LHC computing system, the LHCC referees had several discussions with the LCG Project team, and the Project was presented to the Open Session of the LHCC meeting in October 2002 as well as being discussed with the LCG group in the corresponding LHCC Closed Session.
The Committee considers that Phase 1 of the LCG Project is a necessary step towards the construction of the LHC computing system. The execution of the Project requires the immediate deployment of the organisation structure and of the basic infrastructure necessary for the realisation of the LHC computing network.
To this end, the use of GRID tools, the collaboration of the many Regional Computing Centres, including CERN, and the coherent development of the common software tools used by the four LHC experiments, are essential components of the project. The construction at CERN of the Tier-0 prototype allows CERN to play a central contributing role to the Project and the Committee encourages the realisation of the Tier-0 prototype at CERN.
Moreover, the construction of an appropriately sized and technologically advanced computing center, with links to the Regional Computing Centers through the Grid technology, is considered to be a necessary step in designing Phase 2 of the LCG Project, which must be ready in 2007.
The LHCC considers the LCG Project team to be very well organised and competent to undertake the task. The Steering Committee (SC2) and the Project Execution Board (PEB) of the Project, the identified objectives, and the participation of the Regional Computing Centres to the definition of the projects and in the decision making process, constitute the basis for a successful initiative.
The LHCC strongly supports the LCG Project as it considers the initiative to
be a very important strategic step toward the success of the LHC computing. The
Committee will continue monitoring the project in the future.
It is realistic to expect CMS to install an initial working detector suitable for the LHC pilot run starting in April 2007 and for the physics run starting in August 2007, although the completion of thedetector installation can be foreseen beyond this date. The LHCC considers that the CMS schedule to achieve this is challenging. The LHCC noted that additional resources, both in terms of money and manpower, would aid in accelerating the current CMS schedule, and thereby wouldensure a timely completion of the initial detector in 2007.
In the event that additional funding is not available to ensure completion of CMS in 2007 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 has been prepared. The proposed staging plan for the experiment is aimed at having a small as possible adverse impact on the Higgs and SUSY sensitivity at a luminosity of order 1033 cm-2 s-1. In these circumstances, the installation of staged components, in a shutdown after the completion of the low luminosity running, while requiring additional resources, would complete the CMS detector as described in the approved Technical Design Reports for high luminosity running.
The third annual LHCC Comprehensive Review of CMS took place on 30 September and 1 October 2002. The LHCC referees addressed the following areas: Tracker, Electromagnetic and Hadronic Calorimetry, Muon Spectrometer, Trigger/DAQ, Computing/Software, 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.
The majority of detector sub-systems are now well into the construction phase. Plans for their installation in CMS are being prepared
The construction of the large solenoid magnet, a time-critical component of the Common Projects of CMS, is progressing satisfactorily.
Progress on problems reported at the previous CMS Comprehensive Review has been clearly demonstrated. The remaining critical items are being addressed by the Collaboration in order to recover as much as possible the incurred delays.
- The LHCC considers that the Pixel Vertex Detector is
progressing well but expressed its concern at the delays in the
front-end drivers, power supplies and the front-end hybrid electronics of the Silicon Strip Tracker.
- The Committee noted the impressive progress on the
Electromagnetic Calorimeter since the last Comprehensive
Review but remains concerned about the very tight schedule for the Electromagnetic Calorimeter electronics and the
timely availability of funds for the purchase of the End-cap Electromagnetic Calorimeter crystals.
- The LHCC noted the good progress in the Trigger and
DAQ Project and awaits submission of the DAQ Technical
Design Report by the end of 2002 and a detailed commissioning and integration schedule of the Trigger and DAQ.
- The Committee noted the good progress in both the
Physics Reconstruction and Selection as well as the Computing
and Core Software projects and expressed its satisfaction with the progress.
The Committee is currently reviewing the Addendum to the ECAL TDR.
Following further questions and discussions, the referees will make a full
report on the Addendum to the ECAL TDR at the next meeting of the LHCC.
The Committee has no major concerns. An ancillary document (LHCC 2002-038 /
G-017) 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 ALICE 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 recommends general approval of the ALICE Addendum to the
Time-of-Flight Technical Design Report. The LHCC considers that 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.
The referees reported on the photodetection system for the RICH detectors. Good progress was reported on the HPD bump-bonding. The pixel chip was tested successfully at 40 MHz and the photodetector detection efficiency was measured to be over 80%. Development of the HPD will continue until the end of 2002, at which point a decision will be taken on whether to continue with the HPDs or switch to the MaPMT back-up option. Progress was also shown on the plan for developing the MaPMT option.
Given the results obtained with the ageing tests at the Gamma Irradiation Facility (GIF) and the requirements of the LHCb muon spectrometer for physics, the LHCb Collaboration has decided to abandon the RPC technology and replace it with MWPCs throughout the detector.
The LHCb Inner Tracker Technical Design Report will be submitted in time for the November 2002 meeting of the LHCC. The Technical Design Report for the re-optimisation of the LHCb detector was scheduled for submission by the end of 2002, but LHCb requests to postpone its submission to September 2003. The request has resulted from the delay in performing the detector studies with new software that is not finalized. Still pending is also the design of the RICH-1 shielding and the TT tracking station. The LHCC will continue monitoring the progress of the re-optimisation of the LHCb detector and has requested the LHCb Collaboration to make a presentation of the status at the next Open Session of the LHCC.
The referees also reported on the properties of the Outer Tracker gas. The preferred gas mixture is Ar/CF4/CO2 (75/15/10). Although no traces of silicon were found in the system, concern remains on the possibility of etching by the CF4 gas. A possible change of gas to the back-up solution Ar/CO2 (80/20) will not change the detector design and the Outer Tracker group will continue studying both options.
Good progress was reported on the magnet and calorimeters.
A new list of milestones, which is compatible with the April 2007 start-up, was presented. Differences with the previous version of the milestones were noted and the LHCC requests a written summary explaining and justifying the new dates.
The first of the LHCC Comprehensive Reviews and Installation Reviews of
LHCb are scheduled for January and March 2003, respectively.
The LHCC considers that progress by ALICE to secure the 6.9 MCHF cost-toócompletion is positive and the Committee supports the plan being implemented by the Collaboration. The Committee noted and accepted the contingency plans, consisting of deferrals in the PHOS and DAQ systems, to address a potential short-fall of up to 1.2 MCHF of the 6.9 MCHF in the cost-to-completion, and encourages the Collaboration to continue exploring ways to secure the required funds so that the contingency plan is not required to be put into force.
Moreover, the LHCC noted that the additional resources needed to cover the construction and C&I of the initial ATLAS detector have been estimated to be about 68 MCHF. The present plan is based on the availability of 47 MCHF. The LHCC considers that the plan of ATLAS is reasonable and encourages the Collaboration to continue discussions with the funding agencies before implementing this further staging of the Higher-Level Trigger/DAQ as this would leave no margin in the Level-1 Trigger, severely affecting the B-physics programme and reducing the high-PT physics potential.
CMS reported a short-fall of 63 MCHF for the completion of the initial detector. The LHCC considers that the plan to secure the remaining outstanding 12 MCHF is reasonable and encourages CMS to continue discussions with the funding agencies before implementing the scenario of staging 50% of the DAQ (limiting the Level-1 Trigger rate to 50 kHz) and some of the end-cap RPC chambers in addition to the already staged fourth end-cap muon station and third forward pixel disks.
In all cases, the LHCC noted that the non-availability of the total
costs-to-completion would lead to a clear reduction in physics capability,
which must be rectified if the full potential of the LHC is to be realised.
Since the May 2002 LHCC meeting, the RD50 Collaboration has organized its programme into two major research lines ó Materials Engineering and Device Engineering - and appointed the respective project conveners. In addition, the Collaboration has developed a work plan, together with a set of milestones, for the first year.
The LHCC noted that RD50 has been approved to study radiation hard
semiconductor devices for future very high luminosity colliders and not to
develop the final detectors. The Committee requests that documentation be
submitted detailing the individual research areas and their goals, together
with the associated resources and the collaboration members specifically
responsible in each area.
He summarised the test beam activities of the LHC experiments at the SPS and PS, including the prolongation of the SPS proton run by 8 days, and noted that the SPS beam time in 2002 was sufficient and used efficiently.
The draft of the 2003 PS and SPS schedules were presented. The SPS Fixed Target Programme starting on 19 May consists of 1 week of LHC-type bunched beams and a 15-week nominal proton run. The proton run will end on 7 September and will be followed by a 5.5-week Indium run. The exact schedule of the LHC-type beams has not yet been decided. The PS machine schedule is similar to 2002 and will run for a total of 171 days.
The LHCC stressed the importance of taking due account of the requests for
ageing tests of several final RPC detectors at the Gamma Irradiation Facility
Dates for 2003:
LHCC Secretariat: Janet Grant (Bldg. 14/4-022) Tel. 73424