CERN/LHCC 2002-006
LHCC 56
29 January 2002  
LARGE HADRON COLLIDER COMMITTEE

Minutes of the fifty-sixth meeting held on

Wednesday and Thursday, 23-24 January 2002



 
 
 
 

OPEN SESSION:             1.    LHCb DAQ and Experiment Control Technical Design Report: (LHCC 2001-040 / TDR 7) B. Jost

             2.    Status of the LHC Project: L. Maiani

             3.     RD39 Status Report: T. Niinikoski

            4.     ALICE Status Report: J. Schukraft
 

CLOSED SESSION:

Present:     W. Bartel, S. Bertolucci, J.-J. Blaising*, M. Calvetti (Chairman), R. Cashmore, D. Cassel, J. Dainton,
                  M. Delfino*, B. Di Girolamo*, A. Ereditato, F. Ferroni, M. Hauschild, H.-J. Hilke*, M. Jaffre,
                  H. Hoffmann*, Y. Karyotakis, B. Löhr, M. Mangano, J. May*, J. Nash, J. Panman, K. Potter*,
                  L. Roberston*, D. Schlatter, H. Tiecke, K. Tokushuku, P. Szymanski*, E. Tsesmelis (Secretary), C. Vallée

                                                                                                    *) Part time

Apologies: A. Ceccucci, P. Lebrun, L. Maiani, P. Seyboth

 
          1. INTRODUCTION The minutes of the fifty-fifth LHCC meeting (LHCC 2001-039 / LHCC 55) were approved with the following modification: in point 2 (report from the ALICE referees), the second sentence in the second paragraph should be replaced by `The LHCC considers that before a formal recommendation can be made, further discussions with ALICE on outstanding questions, such as the interpretation of test beam results, the effectiveness of linking tracks between the TRD and TPC and the exact detector configuration to be constructed given that currently only half the costs are covered, is necessary.í

The Research Director for Collider Programmes reported on issues being currently considered to appraise the status of the LHC programme. He also referred to the technical difficulties would may result in changes to the LHC schedule. Any revision to the schedule will be made by March 2002. Currently, there are two main concerns: the procurement of the superconducting cable for the dipole magnets and the civil engineering at Point 5 and elsewhere. Finally, he reported that detailed reviews of the installation of the ATLAS and CMS experiments will be set up later in the year.
 

2. REPORT FROM THE ALICE REFEREES

The Committee heard a report from the ALICE referees, concentrating on their reactions to the TDR for the Transition Radiation Detector (TRD). The TRD, in conjunction with the Inner Tracking System (ITS) and the Time Projection Chamber (TPC), will provide electron identification in heavy-ion running in the central barrel region at momenta in excess of 1 GeV/c. In addition, the TRD will be used to trigger on high-pt (> 3 GeV/c) particles, thus providing not only enriched samples of ° particles, but also the capability to select jets. Thus, the TRD will contribute to charm and beauty physics, to the topological trigger function for the High Momentum Particle Identification Detector (HMPID) and to the measurement of jets in the heavy-ion programme as well as in the ALICE proton-proton physics programme.

W. Bartel reported on the cost evaluation of the ALICE Transition Radiation Detector. He reported that its costing is reasonable and that it fits into the overall cost of the experiment. The cost estimate is based on quotes from industry and from prototype work and it includes spare parts. The manpower required for the project is at the level of that available in the Collaboration.

P. Szymanski presented the ALICE requirements for test beams at CERN. He presented information on the use of test beams for the ALICE sub-detectors and provided the experimentís long-term requirements. ALICE carries out their beam tests principally in the T10 zone of PS East Hall and also at the X5 (including the Gamma Irradiation Facility), H4 and H6 areas at the SPS. Test beam activities for the coming years are required for the completion of the sub-detector development, system tests and the calibration and quality control of the sub-detector series production. Test beams at the PS East Hall and at the SPS are requested for the years up to and including 2005, with the peak request being for 2004. Assuming that the provision of the higher-priority proton beams are adequate, the request also includes tests using heavy-ion beams at the SPS of between one to three weeks in each of the years 2003 to 2005. Following further questions and discussions, the LHCC will provide its recommendations concerning the ALICE test beam programme at its next session.

The referees also provided a status report of the ALICE Trigger. Progress in the past year has been made on finalising the lay-out of the forward detectors, which will provide the inclusive triggers, and updating the central trigger specifications, which has led to a User Requirement Document approved by the ALICE Technical Board. The next steps include an update to the milestones of the Central Trigger Processor and the preparation of a User Requirement Document for the Local Trigger Unit. A combined TDR with the DAQ will be submitted in 2003. The LHCC also requests ALICE to present at the March Comprehensive Review information on the status of the High-level Trigger and an overview of the functionality of an integrated trigger, DAQ and high-level trigger system.

The referees also provided updates to the status of the sub-systems and reviewed their milestones. In particular, the status of the Time-of-Flight detector was reviewed. Although progress has been made on the chamber material and mechanics, further development of the front-end electronics is needed in time for the submission of the TDR. The submission of the TDR has been delayed and will now be sent to the LHCC for the May 2002 session of the Committee.

Moreover, discussions are in progress with new groups from the United States and Japan with a view to join the ALICE Collaboration.

The next LHCC Comprehensive Review of ALICE will be held in March 2002.
 

          3. REPORT FROM THE ATLAS REFEREES
    The Committee heard a report from the ATLAS referees, concentrating on the discussions concerning test beams, the review of various sub-systems, the costs-to-completion and the schedule.

    B. Di Girolamo presented the ATLAS requirements for test beams at CERN. He presented information on the use of beam tests for the ATLAS sub-detectors and provided the experimentís long-term requirements. The SPS H6 and H8 beams are the primary ATLAS test beam zones, while a number of tests are also performed at the SPS Gamma Irradiation Facility. Test beam activities for the coming years are required for a) the calibration and performance checks of the calorimeters, b) the muon alignment and trigger studies, c) the completion of the Inner Detector components and d) the combined operations of a number of sub-systems as a means of pre-commissioning the ATLAS experiment. Priority is given to the years up to and including 2004, for which 15 to 20 weeks of SPS operation are required per year to carry out the above programme, although the tests could also be accommodated within 15 weeks. Requests for further SPS running with the 25 ns bunch structure were also made. Following further questions and discussions, the LHCC will provide its recommendations concerning the ATLAS test beam programme at its next session.

    The referees also reported on the status of the TRT and SCT. Tests on the glass tube joint of the Barrel TRT, which separates the wires of the straws in two halves, showed that after an irradiation to a charge equivalent to about 1 month of high-luminosity operation, much of the glass has been etched-away resulting in HV-breakdown of the straw. Production of the wire joints and their stringing has been stopped. ATLAS is looking for replacement material for the wire joint and is also investigating an alternative gas mixture. First results will be available in February and a decision on the solution will be made in May. Promising results with the new hybrid electronics were shown for SCT end-cap module which had been previously exhibiting higher-than-expected noise. A decision on the final electronics will be made in February. The LHCC will continue monitoring the progress on both these issues.

    The Committee also heard a report on the ATLAS LAr calorimeters. Good progress was reported on the electrode production, the cryostats and preparations for the calorimeter integration. Concerns still remain over the presampler production facility and the challenging FCAL schedule. Series production of the on-detector electronics is starting and the installation procedure of the calorimeters in the ATLAS experiment is being developed.

    Concerning the schedule, a new version (Version 5) is being prepared and will include a revised detailed installation sequence of each sub-detector. The official Version 5 will be made available after discussions with the ATLAS sub-detectors and after the new LHC schedule has been released. A draft will be available for the ATLAS Comprehensive Review in July.

    The LHCC continues to monitor the ATLAS cost-to-completion. A financial plan to complete the detector is being developed and ATLAS appears to be making progress in ensuring a viable funding strategy.

    Finally, at the last session of the LHCC, the Committee requested ATLAS to provide a plan for the case in which the required supplementary funding will be only partially available for the initial detector. ATLAS is now preparing scenarios.
     

          4. REPORT FROM THE RD39 REFEREE
    The Committee heard a report from the RD39 referee on the programme of the Collaboration concerning the operation of solid-state detectors at low temperatures in a high radiation background environment. The referee summarised the theoretical and experimental results that RD39 has achieved on the operation of such detectors and also described the proposed programme for future work.

    The LHCC takes note of the collaborative work between RD39 and the experiments COMPASS, NA60 and TOTEM. The LHCC will review these common efforts in an upcoming meeting of Committee.

    The LHCC recommends that the Collaboration prepares a plan for the coming two years emphasising a) the basic research and device physics and b) the sensor design and operation together with the read-out chain. The plan should include information on the division of responsibilities within the Collaboration and the required budget for each of the participating institutes.
     

          5. ALICE TRANSITION RADIATION DETECTOR TDR
    The LHCC has completed its scientific, technical, and cost evaluation of the ALICE Transition Radiation Detector TDR submitted in October 2001. The Committee was impressed by the quality of the work presented in the TDR and congratulates the Collaboration. The technology and design of the Transition Radiation Detector are well-suited to provide electron identification as well as triggering for high momentum particles and are adequate to achieve the physics goals stated in the ALICE Technical Proposal.

    An ancillary document (LHCC 2001-038) contains items that the LHCC has noted for further evaluation 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 an independent review of the engineering design. Written reports should be made available to the LHCC through its referees.

    Recommendation:

    The LHCC recommends general approval of the Technical Design Report of the ALICE Transition Radiation Detector. However, the Committee takes note of the current funding situation as described in the ALICE MoU, which makes available funds corresponding to about 58% of the total detector surface area. The LHCC, therefore, recommends construction of the `Short Asymmetricí version as described in the TDR which consists of three out of the five azimuthal rings. 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.
     

          6. REPORT FROM THE CMS REFEREES The Committee heard a report from the CMS referees, concentrating on the review of the test beams, Tracker, ECAL and Muon Detector, and the schedule, milestones and cost-to-completion.

E. Tsesmelis presented the CMS requirements for test beams at CERN. He presented information on the use of beam tests for the CMS sub-detectors and provided the experimentís long-term requirements. The SPS H2 and H4 beams are the primary CMS test beam zones, while a number of tests are also performed at the SPS X5 and Gamma Irradiation Facility. Test beam activities for the coming years are required primarily to carry-out performance checks and quality control of the detector components from the series production and to calibrate the calorimeters. According to the current schedule, beam time will be requested up to and including 2006, with the peak request being for 2004. The years 2005 and 2006 are needed to complete the calibration of the ECAL. Requests for further SPS running with the 25 ns bunch structure were also made. Following further questions and discussions, the LHCC will provide its recommendations concerning the CMS test beam programme at its next session.

The referees also reported on the status of the Tracker and the Pixels. Tests of the Tracker with the 25 ns bunched-beam gave rise to two effects: HIPS and Pinholes. The former effect is related to the large deposition of charge in several channels following a nuclear interaction in the sensor leading to the saturation in the APV baseline while the latter concerns the pinhole effects of the sensor AC coupling capacitor of the APV. CMS is evaluating these effects and will report back to the LHCC in upcoming meetings. Moreover, it was reported that the hybrid is late and the current design appears to be difficult and expensive to mass-produce in industry. A new strategy includes the use of encapsulated chips, which offer a better reliability and easier manufacture. Although, this will cause a delay of about six months in the start of production, the LHCC considers that it is a reasonable way to proceed in order to ensure a reliable hybrid.

The referees also gave a status report on the ECAL. Good progress was reported on the production of the ECAL crystals and the APDs. The problems with the noise in the FPPA read-out electronics have been identified to be related to stray impedance. In order to keep to the overall CMS schedule, the next submission of the FPPA, now scheduled for September 2002, must be the final one. In the meantime, working groups on the ECAL electronics have been set up to review the overall electronics of the sub-detector. Moreover, work is underway to prepare the first supermodule for beam tests in the summer, albeit not with the final electronics. Finally, the LHCC had a preliminary discussion on the ECAL calibration strategy leading to the absolute energy scale. Further discussions with CMS on the calibration strategy are scheduled before and during the next meeting of the LHCC.

The referees also presented the status of the Muon Detectors. Questions still persist concerning the production rate of the Drift Tube chambers and the schedule, quality control and logistics of the RPC production.

The LHCC continues to monitor the CMS milestones and cost-to-completion. A more detailed report on the schedule and milestones, taking into account changes to the overall LHC schedule, will be presented at the next LHCC meeting. A financial plan to complete the detector is being developed and CMS appears to be making progress in ensuring a viable funding strategy.

Finally, at the last session of the LHCC, the Committee requested CMS to provide a plan for the case in which the required supplementary funding will be only partially available for the initial detector. CMS is now preparing scenarios.
 

7. REPORT FROM THE LHCb REFEREES

The Committee heard a report from the LHCb referees, concentrating on the review of the test beams, the Data Acquisition and Experiment Control TDR, progress on re-optimizing the detector and the status of several of the sub-systems.

H.-J. Hilke presented the LHCb requirements for test beams at CERN. He presented information on the use of beam tests for the LHCb sub-detectors and provided the experimentís long-term requirements. The SPS X7 beam is the primary LHCb test beam zone, while a number of tests are also performed at the PS (T7 and T11) and at the SPS Gamma Irradiation Facility. The beams are used for final prototype and pre-production tests of detectors and electronics, for quality assurance of the detector series production and system tests. The preliminary conclusions from the review of the LHCb test beams indicate that LHCb prefers any cuts in the CERN accelerator operation to be spread over the future years but if the accelerators are to be closed for a full year, then it should be in 2005. Following further questions and discussions, the LHCC will provide its recommendations concerning the LHCb test beam programme at its next session.

The referees, with the support of J.-J. Blaising as a consultant, also reported on their preliminary reactions to the LHCb Data Acquisition and Experiment Control (DAQ/ECS) TDR. The TDR describes a DAQ/ECS system to provide facilities for collecting data from the detector and for configuring and supervising the operation of the detector. In addition, the system must satisfy a wide spectrum of requirements coming from the need to communicate with other systems, such as the trigger. Following further questions and discussions, the referees will make a full report at the next meeting of the LHCC.

The LHCb Collaboration is in the process of re-optimizing the detector by re-examining its material budget. The current number of nine tracking stations has resulted from removing the station in the middle of the magnet and one just behind the RICH-2, as they were shown not to add to the tracking performance. While maintaining the technology and design of the individual tracking detectors, re-optimization of the remaining nine tracking stations is being studied in order to reduce further the amount of material in front of RICH-2. The re-optimization also includes reducing the material in the RICH-1 mirrors and support structures, the number of stations and thickness of the Vertex Locator as well as its shielding and the material of the beam pipe. A progress report will be given to the LHCC in May, followed by the submission in the autumn 2002 of an addendum to the tracker TDRs showing the overall performance and integration of the tracking detectors.

The referees also reported on the status of the HPDs for the RICH. Tests on a prototype show that although the general properties of the HPD are satisfactory, a number of pixels did not respond to a beam of light. Reasons for the prototypeís poor performance appear to be its poor bump-bonding and packaging qualities. A new prototype is being prepared and should be available in April 2002. The LHCC considers that the delays in the HPD are potentially serious and expressed its concern. Despite these technical concerns, the RICH group remains committed to the HPD option. The MAPMT option is still considered as a credible back-up, although it is more costly and more work is needed on the digital read-out.

The referees also presented the status of the infrastructure. The civil engineering in the underground cavern is progressing well and there is good progress on scheduling work between the LHC Machine and LHCb. A major concern remains the planned LHC injection tests in 2004, the interference with the LHCb installation and the problems with radiation safety, which may have an impact on further LHC and LHCb installation.

The referees consider that progress has been made by LHCb in meeting milestones. The potentially most serious delay is that of the development of the HPD for the RICH detector.

W. Bartel reported on the cost evaluation of the LHCb Outer Tracker. He reported that its costing is reasonable and that it fits into the overall cost of the experiment. The cost estimate is based on quotes from industry and from prototype work. It includes spare parts and also an adequate provision of manpower.
 

          8. TEST BEAMS M. Hauschild reported on the SPS and PS Fixed Target Programmes, including the work on the accelerators during the winter shutdown period.

He summarized the beam requests for 2002. Based on these requests, the drafts of the 2002 fixed target programmes for the SPS and PS have been prepared and distributed to the users. No major concerns have been reported and the users have been cooperative in fitting in to the reduced running times of the machines as approved by the Research Board in November 2001.
 

          9. DISCUSSION ON LHC COMPUTING GRID PROJECT Fulfillment of the LHC Computing Grid requirements will, on the same basis as the successful construction of the LHC accelerator and particle detectors, be crucial for the success of the LHC physics programme. In view of this, it was recommended that the LHC Computing Grid Project be treated by the LHCC in a manner similar to that for the experiments with the aim of exploiting fully the physics output of the LHC. The LHC Computing Grid Project will make available to the LHCC for review, documents and reports from the project, including the Technical Design Report. As a first step, and following the appointment of referees, the Committee will analyze the relation between the detector parameters and computing requirements, including the expected experiment trigger rates as a function of the machine luminosity. The LHCC and the management of the LHC Computing Grid Project agree to the above scheme of interaction between the Committee and the Project.

10. REFEREES

Following the changes to the LHCC membership, the new referee teams are as follows:

ALICE: S. Bertolucci, J. Panman (Co-ordinator), P. Seyboth, C. Vallée

ATLAS: A. Ceccucci, J.-J. Gomez-Cadenas, M. Jaffre, K. Tokushuku (Co-ordinator)

CMS: J. Dainton (Co-ordinator), B. Löhr, J. Nash, H. Tiecke

LHCb: D. Cassel (Co-ordinator), F. Ferroni, Y. Karyotakis

MOEDAL: F. Ferroni

TOTEM: J. Nash

11. DATES FOR LHCC MEETINGS

              Dates for 2002:               - Review of the ALICE Transition Radiation Detector Technical Design Report (LHCC 2001-038).*

              - LHCb Online System Data Acquisition and Experiment Control Technical Design Report
                (LHCC 2001-040/LHCb TDR 7).

              - Cost evaluation: TDR on the ALICE Transition Radiation Detector (LHCC 2002-002)*.

              - RD39 Status Report (LHCC 2002-004).

              - Cost evaluation: TDR on the LHCb Outer Tracker (LHCC 2002-005)*

                                                         * Restricted circulation
 
 
 
 
  Emmanuel Tsesmelis
Eómail: LHCC.Secretary@CERN.CH
Tel. 78949, 164057

 
 
 
 

LHCC Secretariat: Janet Grant (Bldg. 14/4-022) Tel. 73424
                               janet.grant@CERN.CH