16 August 2002
LARGE HADRON COLLIDER COMMITTEE
Minutes of the fifty-ninth meeting held on
Wednesday, Thursday and Friday, 3-5 July 2002
1. CMS Status Report: Michel Della Negra / CERN
2. TOTEM Status Report: Giorgio Matthiae / Università di Roma II
3. Report on the ATLAS RPC Detectors: Rinaldo Santonico / Università di Roma II
4. Report on the CMS RPC Detectors: Giuseppe
Iaselli / Università & INFN Bari
S. Bertolucci, M. Calvetti (Chairman), R. Cashmore, D. Cassel, A. Ceccucci,
J. Dainton, M. Delfino*, U. Dosselli*, J. Feltesse,
F. Ferroni, M. Hauschild, H. Hoffmann*, M. Jaffre, B. Löhr, M. Mangano, J. Nash, J. Panman, K. Potter,
L. Robertson*, W. von Rueden, D. Schlatter*, P. Seyboth, H. Tiecke, K. Tokushuku, E. Tsesmelis (Secretary), C. Vallée,
I. Videau* (representing D.Schlatter), V. Vuillemin* (representing D. Schlatter)
*) Part time
2. REPORT FROM THE DIRECTOR FOR COLLIDER PROGRAMMES
The Director for Collider Programmes informed the Committee on various issues concerning the LHC programme.
He reported on the June Council meetings. Council accepted the outline plan for 2003. An updated financial plan for the LHC will be submitted to Council for approval in December 2002. He also noted that CERNís application for a 450 MCHF loan to the European Investment Bank has been successful and detailed negotiations will now proceed.
Council also accepted the report from the External Review Committee. The report underlines the sound technical basis of the LHC and the ability of the CERN staff to carry-out the project. Recommendations of the External Review Committee are being implemented.
A regular annual review of the LHC Machine project is being implemented and will scrutinize the projectís work packages. Earned-value reporting is also being introduced.
Concerning the experiments, the installation reviews of ATLAS and CMS and a heavy-ion technical review will all take place in September 2002. The Collaborations are also working towards refining their costs-to-completion and the on-going discussions with funding agencies are proving to be positive.
primarily to save on costs, the SPS and PS Complex accelerators will be closed
in 2005 and a reduction of 20% to the Fellows and Associates programme is being
implemented. It was also noted that the current cutbacks in CERNís fixed-target
programme and accelerator R&D need to be addressed and that the SPC and ECFA
endorse the needs for extra resources.
3. REPORT FROM THE CMS REFEREES
The Committee heard a report from the CMS referees, concentrating on the status of the electronic systems, the ECAL, the muon spectrometer, the Tracker, integration, schedules and milestones.
CMS has adopted a common detector-wide approach to data links based on the Tracker link technology and using common transmission protocols. The Collaboration has also adopted a common approach to the low-voltage power transmission based on a 400 Hz, 400 V system with AC-DC converters located on the magnet, saving CMS about 4000 power cables, 5 months of installation and about 5 MCHF as a result.
Some progress was reported on the ECAL. Detailed specifications of the new electronics have been completed and the LHCC considers that the new electronics design is reasonable. The data links based on the Tracker link technology have been demonstrated at both 800 Mbps and 1600 Mbps and the design of the off-detector electronics is specified and responsibilities for detailed design agreed. A detailed study of all the electronics integration issues for the ECAL, including cooling issues, has been successfully completed and prototyping of the new design has commenced. CMS is preparing for submission to the LHCCís October 2002 session an Addendum to the ECAL TDR describing the changes to the projectís electronics. Finally, a system test of the M0í module at the SPS in July and August 2002 is on schedule. The Committee considers the project of the ECAL electronics to be on the critical path.
The LHCC noted the delay in the production of the Drift Tube chambers. CMS expects to meet the milestone of having 10% of the chambers constructed by the end of July 2002, which corresponds to a 2-month delay with respect to the latest V33 CMS schedule for having about 70 chambers ready by the end of 2002. The LHCC considers that the delays are recoverable. Moreover, the Committee noted the delay in the production of the Drift Tube Minicrate electronics, which consist of the read-out and trigger electronics. The Minicrates are now on the critical path for installation in the first chamber wheel.
Progress was reported on the Tracker front-end hybrids and the Committee does not consider the current problems related to the flex to be critical.
The referees reported on the V33 schedule, the latest version of the CMS general schedule, and the Level-2 milestones. The schedule and milestones are to be considered for approval at the Committeeís October 2002 session.
Finally, an integration commissioning task force has been created to take charge of the 4 sub-projects crucial for installation of CMS at Point 5. The task force will consider the magnet and sector integration tests, the testing of the CMS detector systems, the DAQ slice tests in surface building SX5 and the UXC55 infrastructure installation.
next CMS Comprehensive Review will be held on 30 September and 1 October 2002.
4. REPORT AND DISCUSSION ON THE ATLAS AND CMS RPC DETECTORS
U. Dosselli reported on the deliberations of the INFN committee coordinating production of RPCs at the Italian firm General Technica. The committee was set up in 2001 to manage the RPC production of all interested groups, currently consisting of the respective groups in ALICE, ARGO, ATLAS, BaBar, CMS, LHCb, and OPERA, in an effort to streamline and coordinate the manufacture.
The LHCC noted the general progress of the production at General Technica and in particular that manufacture of chambers for the LHC is underway. The LHCC, however, re-iterated its concerns on production uncertainties given the recent changes in the bakelite material and changes at the production site. In view of this, the LHCC requests that ATLAS and CMS perform tests at the GIF of several final chambers before the end of the 2002 SPS proton run in September. Moreover, ageing tests should continue after the beam tests. A detailed schedule of when the chambers will be brought to CERN and installed in the GIF and the test plans are to be discussed with the SPS/PS Physics Coordinator and communicated to the LHCC referees. Specifications for the required gas should be discussed with the relevant staff in EP Division. A status report should be given to the LHCC referees for the Committeeís October 2002 session with a final written report to be submitted when the ageing tests are completed at the end of 2002.
LHCC also requests by September 2002 documentation resulting from a joint
meeting between the ALICE, ATLAS, CMS and LHCb RPC groups on comparing the
performance of their respective chambers.
5. REPORT FROM THE ALICE REFEREES
The Committee heard a report from the ALICE referees, concentrating on the general status of the experiment, the status of the HAL25 front-end chip for the SSD, the organization of the Trigger/HLT/DAQ, the impact of the PS shutdown in 2005 and the updated milestones.
Good progress was reported on the TPC, SDD, TRD and the Forward Dimuon Spectrometer. Problems with the low yield of the HAL25 chips for the SSD are being investigated. The LHCC took note of the document describing the impact of the re-location of the HMPID inside the L3 magnet.
The beam test of a full TPC sector will serve as a test bed for the integration of the DAQ/HLT functionalities. The referees did note that although these tests will clarify the DAQ/HLT interface to the front-end, the tests will not address the farm architecture and protocols. This latter issue will need to be addressed independently. Moreover, the Read-Out Interface (ROI) transfer is not covered by any institute and a single coordinator for the TDR has not yet been nominated. The TDR for the Trigger/HLT/DAQ is scheduled for submission in summer 2003.
The LHCC noted that the ALICE test beams have been re-organized following the decision to shutdown also the PS in 2005 and that ALICE requests an early start of beam tests in 2006.
Finally, a list of
updated ALICE milestones were reviewed by the LHCC referees. The schedule and
milestones are preliminary and the LHCC will continue its review at its October
6. ALICE ADDENDUM TO THE TIME-OF-FLIGHT TECHNICAL DESIGN REPORT
The LHCC heard a report on the ALICE Addendum to the Time-of-Flight (TOF) Technical Design Report. The Committee was impressed by the quality of the work presented in the Addendum to the TDR and congratulates the Collaboration. The Addendum to the TDR describes a detector based on Multi-gap Resistive Plate Chambers (MRPCs), whose general concept and choice of technology are well-suited for the time-of-flight measurement required to separate kaons and protons from pions and which is adequate to achieve the physics goals stated in the ALICE Technical Proposal.
In particular, tests on full-scale prototype TOF strips exhibit a performance that fulfils the requirements specified in the TDR. The detector technology, including the double-gap configuration, the choice of materials, the strip lay-out, and the module engineering are considered to be sound. The operation principle of the detector is well understood and satisfactorily reproduced by simulation. Two solutions for the front-end electronics are still under consideration: an available solution based on commercial components and a custom solution, currently under development, that is based on an ASICs design.
The ASICs solution, if successful, would greatly reduce the heat load of the detector.
Issues related to
the overall detector system aspects, primarily concerning the front-end
electronics, are still under discussion between the referees and the ALICE TOF
group, and require clarification before final recommendation of the project.
7. ATLAS COMPREHENSIVE REVIEW
Since the previous ATLAS Comprehensive Reviews in July 2001, the ATLAS 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 2007. In particular, construction of the majority of the final components is well-underway.
It is realistic to expect ATLAS to have an initial working detector for the start of LHC operation in April 2007, although detector installation can be foreseen beyond this date. However, the LHCC considers that the ATLAS plan to have commissioned an initial working detector by the end of 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, and the LAr End-cap A are considered to be critical. The LHCC observes that additional resources, both in terms of money and manpower, would aid in completing the initial detector.
Detector elements not installed by April 2007 will be staged. The staging plan consists of deferring installation of some components of the Inner Detector, the Calorimetry, the Muon Instrumentation, the Higher-level Trigger, DAQ and the radiation shielding. Their installation in a long shutdown, while requiring additional resources, would complete the ATLAS detector as described in the approved Technical Design Reports.
The LHCC considers that the initial working detector, in time for start of LHC operation in April 2007, 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 Higgs and SUSY searches at a luminosity of order 1033 cm-2 s-1 but the B-physics programme will be significantly reduced.
- The LHCC has no major concerns regarding the Pixels and SCT, although it will continue monitoring progress particularly for the CuNi cooling pipes of the barrel SCT. The Committee expressed its deep concern on the problems with the wire-joint and gas mixture of the barrel TRT and urges ATLAS to continue evaluating the identified options and to report back to the Committee in October 2002.
Good progress was reported on the LAr calorimeters. The major outstanding
problem areas are related to the timely completion of the End-cap A calorimeter,
the negative voltage regulators and the funding profile for the tungsten rods of
The LHCC considers that good overall progress was reported for the Tile
Calorimeter. The outstanding issues of the tooling for the pre-assembly phase
and the timely availability of electronic components for the Super Drawers will
continue to be monitored by the Committee.
The LHCC noted the good progress on the MDT, CSC and TGC detectors and considers
that the ATLAS plans to overcome the outstanding problems are reasonable. The
Committee did express serious concerns regarding both the mechanics and
electronics of the RPCs and invites ATLAS to submit additional detailed
documentation to forthcoming meetings of the LHCC for further review of the
project. Documentation for October 2002 should consist of the status of the
ageing tests at the GIF, the conclusions from the joint meeting with the other
LHC RPC groups and the report on Quality Control and Assurance, while a final
report on the RPC ageing tests is to be submitted by the end of 2002.
Good progress was reported on the Level-1, Higher-level Triggers and the DAQ and
the Committee expressed no major concerns. The Committee noted the change in the
project management structure and expects similar progress in the future.
The LHCC considers that good progress has been reported on the ATLAS computing
and software project. The primary concerns are the delays in moving towards the
new modular object-oriented ATHENA framework and the lack of a priority list of
goals for the Data Challenges.
- The LHCC considers that the detector proposed by ATLAS to be commissioned in time for the start of LHC operation in April 2007 is capable of searching for the Higgs and SUSY at the 10 fb-1 luminosity level, although installation of staged items will be necessary for
The LHCC noted progress in the construction of the barrel and end-cap toroid
magnets, although the schedule for their installation remains critical. The
Committee considers that it is realistic to expect ATLAS to install an initial
working detector for the start of LHC operation in April 2007, although detector
installation can be foreseen beyond this date.
Given the limited resources, both in terms of manpower and funds available within the TOTEM Collaboration, the LHCC recommends that TOTEM continues with the development of their experimental apparatus by concentrating on building the baseline detector capable of meeting the approved goals of the TOTEM Technical Proposal. The baseline detector, together with a description of the various responsibilities and costs, are to be described in the TOTEM Technical Design Report to be prepared by the end of 2002.
The LHCC also
encourages TOTEM to continue their efforts in integrating with CMS and the LHC
Machine. In particular, mechanical integration with CMS should be such that the
overall envelopes are respected and that the TOTEM detectors can be installed
and removed rapidly and with minimal impact on the CMS programme and detector.
Moreover, integration and compatibility of the TOTEM Trigger/DAQ with that of
CMS would provide the added value of combined runs with the latter. Finally,
discussions with the LHC Machine on the location of the Roman Pots should
10. REPORT FROM THE LHCC WORKSHOP ON ION PHYSICS AT THE LHC
P. Seyboth reported on the recent LHCC workshop on ion physics at the LHC. He reminded the Committee that a technical review of heavy-ions at the LHC and its injectors will be held later in 2002 and that in view of this the LHCC held a one-day workshop on 28 June, 2002 to collect and consolidate the requirements from the ALICE, ATLAS and CMS experiments concerning their desired running conditions ? luminosities, energies, type of collisions, e.g. ion-ion (both Pb-Pb and lighter species), p-p, and p-N.
The conclusions and recommendations from the workshop are given below:
- Due to the complementary detectors and nature of the respective physics searches, participation of ALICE, ATLAS and CMS would be of great benefit and value to the LHCís ion physics programme.
- As experience at RHIC shows, an early exploratory Pb run of a few days duration in 2007 is considered to be very desirable. This would already allow many measurements to be made including the particle multiplicity, energy density, and thermodynamic properties of the Pb-Pb collisions.
- An extended Pb-Pb run should follow in 2008 and in subsequent years with the aim of collecting about 1 nb-1 of integrated luminosity to
13. DATES FOR LHCC MEETINGS
Dates for 2002:
The LHCC received the following documents
- Cost evaluation - TDR on the ALICE Time of Flight Detector (LHCC 2002-021).*
Emmanuel Tsesmelise-mail: LHCC.Secretary@cern.chTel. 78949, 164057