CERN/LHCC 2003-005

                                                                                                                             LHCC 62

                                                                                                                 18 February 2003

                                                                                                         

LARGE HADRON COLLIDER COMMITTEE

 

Minutes of the sixty-second meeting held on

Wednesday and Thursday, 29-30 January 2003

 

 

OPEN SESSION:

1.      Status of the LHC Project: Luciano Maiani

2.      ALICE Status Report: Juergen Schukraft (pdf) (ppt)

3.      CMS Data Acquisition and High-Level Trigger TDR: Sergio Cittolin (pdf) (ppt)

4.      Study of Possible Dangerous Events During Heavy-ion Collisions at the LHC: Graham Ross (pdf) (ppt)

 

 

CLOSED SESSION:

Present:      S. Bertolucci, K. Borras, M. Bozzo*, M. Calvetti (Chairman), R. Cashmore, A. Ceccucci, J. Dainton, K. Eggert*, J. Feltesse, F. Ferroni,
J.-J. Gomez Cadenas*, M. Hauschild, M. Jaffre, Y. Karyotakis, Y.-K. Kim, J. Knobloch, B. Löhr, M. Mangano, J. Martin, J. May*, P. McBride, J. Nash, M. Oriunno, J. Panman, K. Potter, D. Schlatter, P. Seyboth, H. Tiecke,
K. Tokushuku, E. Tsesmelis (Secretary), C. Vallée

 

                                                                                                            *) Part time

 

1.       PROCEDURE

The minutes of the sixty-first LHCC meeting (LHCC 2002-044 / LHCC 61) were approved without modification.

 

2.       INTRODUCTION

The Director for Collider Programmes informed the Committee on various issues concerning the LHC programme.

The December 2002 Council session concentrated on discussions of CERN’s long-term plan up to 2010, including an in depth review of CERN personnel and material needs and projections and approval of a loan from the European Investment Bank. Agreement on the financing and timescale of the LHC was reached between all Member States, and is considered as a major step forward.

Re-organisation of CERN manpower has gone ahead in an effort to better align the resources with the needs of the LHC Project. In particular, restructuring of the accelerator sector has been made with the magnet testing and machine installation phases in mind.

The next series of LHCC Installation Reviews for the experiments will be held in March 2003. It will be the first such review for ALICE and LHCb, while there will be follow-up reviews to those in September 2002 for ATLAS and CMS. The reviews will also include a discussion on the experiment commissioning needs, including planning for the Trigger/DAQ and calibration procedures.

The LHCC Magnet Advisory Group (MAG) will review the LHC spectrometer magnets in early February 2003. A report will be submitted to the March 2003 session of the LHCC.

A workshop on the LHC ion injector chain will be held on 26-28 March 2003 at CERN. The workshop will focus on the technical requirements for the LHC injector chain when running in heavy-ion mode.

Good progress was reported on the LHC Computing. Preparations for the Computing Resource Review Board are underway with the Project Overview Board set to meet in February 2003.

The LHCC also discussed issues arising from the Open Session. The conclusions from the recent series of workshops on heavy-ion physics at the LHC will be presented to the LHCC in the spring 2003. In addition, the study of possible dangerous events during heavy-ion collisions at the LHC was commissioned by the Director-General in an effort to inform the physics community and the general public. The study showed that “catastrophic scenarios are firmly excluded by existing empirical evidence, compelling theoretical arguments or both.”

 

3.       REPORT FROM THE ALICE REFEREES

The LHCC heard a report from the ALICE referees, which consisted of reviews on several of the sub-systems, the milestones and the next ALICE Comprehensive Review.

The referees reviewed the status of a number of the sub-systems. Good progress was reported on the ITS, TPC, TOF and HMPID. Delays in the TRD project were reported, but due to the flexibility in their installation schedule, the delays are not considered to be critical. The absorber and dipole magnet for the muon system are on track but the prototype of Station 1 of the tracking chambers was found not to work correctly. This is of concern, as the causes are not yet fully understood and the LHCC has asked for a detailed account of the status at its next session. In order to respect the ALICE `Ready-for-Installation’ date, construction of the final chambers must start by September 2003. The Addendum to the PMD Technical Design Report is in preparation. Good progress was reported on the DAQ Data Challenges. Concerns were expressed regarding the coordination between the DAQ and HLT and the ALICE Management is working to solve the problems in this area.

The LHCC took note of the ALICE LHCC milestones and noted the potential problem arising from certain milestones being missed even after a recent re-baselining.

The next ALICE Comprehensive Review will be held on 24-25 March 2003.

4.       REPORT FROM THE ATLAS REFEREES

The LHCC heard a report from the ATLAS referees, concentrating on a general progress report of the sub-systems, the schedules and milestones and items of concern.

Good progress was reported on the toroid magnets and LAr calorimeters, although the Barrel Toroid coils 7 and 8, the LAr Barrel Calorimeter and the LAr Endcap Calorimeters have a reduced float in the installation schedule. Installation of the general infrastructure in the underground caverns is proceeding well.

The re-baselining of the ATLAS milestones is underway. The schedule is being re-baselined to take into account the new LHC schedule, which has the machine starting up in April 2007. The exercise will be presented for approval to the ATLAS Executive Board in early February and subsequently submitted to the LHCC.

The referees also reported on concerns in the schedule. Production schedule difficulties for which delays with respect to the `Ready for Installation’ milestones, which include a 4-month float, were reported for the following systems: Barrel Toroid coils 7 and 8, the LAr Barrel Calorimeter, the LAr End-cap Side A Calorimeter, Inner Detector Side A (SCT and TRT) and the TRT Barrel.

The issues for the SCT and TRT are in regard to the DMILL process. The yield for the SCT ABCD electronics has been a concern and understanding of the problem is still lacking. This is affecting both the SCT and TRT schedules, as the latter system also uses the same process for their ASDBLR read-out electronics. Furthermore, the contracted firm has announced the end of production in DMILL in December 2003. Although production for ATLAS should fit into this schedule, close monitoring of the situation is advised.

The LHCC took note that the performance of the SCT Endcap modules after irradiation to 3´1014 p/cm2 just meets the specification. Following the irradiation campaign, the SCT End-cap has now started production with a revised schedule.

The referees also reported on the leaks found in the brass gas tubelets of the MDT chambers. Following a series of tests, ATLAS has decided to reduce the risk and replace the brass with stainless steel, thus finding an acceptable solution to the problem. The extra time needed for the studies should not delay completion of the chambers.

RPC production chambers are being tested at the GIF. A Quality Control procedure is being followed for the RPCs, but after a too-high chamber failure rate during cosmic-ray tests, a stricter quality control procedure may need to be introduced.

The LHCC took note of the Tile Calorimeter schedule. A delay of about 3 to 4 months is now expected in the production of the electronic Drawers, resulting in not all of the Barrel Drawers being commissioned or even inserted in the barrel modules before installation in the underground cavern. In addition, the production schedule and cost of components for the low-voltage power supplies need to be understood further. Finally, it was noted that some pre-assembly work on the surface would need to proceed in parallel with installation in the underground cavern and that a possible solution to avoid this is being worked-out.

The LHCC took note of the document `ATLAS Actions to the LHCC Report CERN/LHCC 2002-040’ (LHCC 2003-043/G021) submitted to the Committee in preparation to the follow-up Installation Review in March 2003.

 

5.       REPORT FROM THE CMS REFEREES

The LHCC heard a report from the CMS referees, concentrating on a general progress report of the sub-systems, the schedules and milestones, items of concern and reviews of the Data Acquisition / High-Level Trigger (DAQ/HLT) Technical Design Report and the Addendum to the ECAL Technical Design Report.

Good progress was reported on the magnet coil, the production of the ECAL Barrel crystals, the assembly of the HE calorimeter, and the production of the CSC End-cap and RPC detectors. The LHCC also took note of the plans for the ECAL test beams in 2003.

The referees reported on the Tracker. The production logistics have been set up and tested at all sites. The Collaboration is starting mass prtoduction with about 30 modules expected in February 2003. Progress was shown for the Hybrid front-end electronics and the Pitch Adapters. The preliminary plan is compatible with the overall CMS schedule but is considered to be very aggressive. Given the tight schedule, the LHCC will continue monitoring closely developments in the Tracker.

The referees also reported on the design status of the forward region in CMS. A decision on what detectors TOTEM and the CMS heavy-ion community want to install in this region is urgent, as the design and construction of the beam pipe and radiation shielding in this region must proceed.

The Committee heard a report on the referees’ preliminary reactions to the CMS DAQ/HLT Technical Design Report. The functionality of the CMS DAQ/HLT system is three-fold: a) perform the read-out of the front-end electronics after a Level-1 Trigger accept, b) execute physics selection algorithms on the events read out in order to accept the ones with the most interesting physics content and c) forward these accepted events, as well as a small number of rejected events, to the online services which monitor the performance of the CMS detector and also provide a means of archiving the events in mass storage. In addition, the DAQ has the important functionality of operating the Detector Control System (DCS) for the operation and supervision of all detector components and the general infrastructure of the experiment. The Committee is currently reviewing the CMS DAQ/HLT Technical Design Report and following further questions and discussions, the referees will make a full report at the March 2003 meeting of the LHCC with the aim of providing a recommendation at the Committee’s meeting in May 2003.

 

6.   CMS ADDENDUM TO THE ECAL TECHNICAL DESIGN REPORT

The Committee heard a report on the referees’ reactions to the CMS Addendum to the ECAL Technical Design Report – Changes to the CMS ECAL Electronics (LHCC 2002-027 TDR 4-Add. 1). The major change proposed in the Addendum to the ECAL TDR is to move the generation of the trigger primitives and the Level-1 data pipelines from the off-detector electronics onto the detector. This implies a) a lower granularity in transmitting the trigger data off-detector; and b) the digitised data, temporarily stored in the on-detector pipelines, can be shipped off-detector only upon a Level-1 accept with the possibility of multiplexing 25 channels in the same data link. This new readout scheme implies a decrease in the number of data links and the quantity of the off-detector electronics by about a factor 8. The other relevant change in the on-detector electronics is the use of low-voltage regulators that allow AC power at 400V to be transmitted directly to the on-detector electronics. This results in a reduction of the number of cables from 1400 to about 10.

The LHCC considers the new system architecture to be elegant and much better optimised to fulfill the detector requirements in terms of data throughput. It is based on a single new ASIC, the FENIX chip, implemented in the IBM 0.25 mm CMOS process. Development of a prototype Front-End (FE) board, very close to the final version, has been completed and will be used as part of a full system test of the new electronics with 400 channels in beam during 2003.

Although the Addendum to the ECAL TDR does not propose any change in the Very Front-End (VFE) electronics of the Floating-Point Pre-Amplifier (FPPA) and ADC, it proposes the development of a fall-back solution, as the VFE is considered to be the most critical item in the whole ECAL electronics. Therefore, the ECAL project has undertaken the development of a fall-back solution based on a Multi Gain Pre-Amplifier (MGPA) and a 12-bit 40 MHz ADC, both of which are implemented in the IBM 0.25mm CMOS process.

The LHCC considers that the risks in the development and production of the new VFE components are not greater than those associated with the production of the FPPA chips, and its major concern with this way forward is the need to make a timely decision which does not jeopardise the overall ECAL schedule and in particular the time windows for the calibration of modules in 2004.

The choice between the FPPA and the MGPA should made by October 2003. In monitoring progress in the immediate future, the LHCC will have this concern very much in mind. The overall ECAL construction schedule is now very challenging and is a source of great concern to the LHCC. The collaboration is urged to take all possible steps to ensure that no further delays accrue. The LHCC will monitor progress closely in the usual fashion using the V33 milestones.

 

7.   TOTEM STATUS REPORT

     The Committee heard a report from Karsten Eggert, concentrating on the status of the experimental design and progress towards the Technical Design Report.

   As approved in the Technical Proposal, TOTEM plans to measure the inelastic and elastic cross-sections in order to provide the important measurement of the total p-p cross-section at the LHC and to calibrate the luminosity monitors. Both these measurements require short runs at relatively low luminosity and with special machine optics. The experimental set-up consists of T1 and T2 telescopes and Roman Pots either side of the interaction point in the warm region of the LHC machine.

Good progress was reported on the development of the RPC and CSC detectors for the T1 telescope. Tests in beam show that the detector technologies proposed for the T1 telescope are adequate to achieve the physics goals stated in the Technical Proposal. Two options are being considered for the T2 telescope: a detector similar to T1 and a silicon tracker. The T2 telescope is being designed with the possibility of running simultaneously with the proposed CASTOR calorimeter in CMS and with an experimental beampipe suitable also to CMS. Furthermore, the design of the silicon-based detectors for the Roman Pots is also continuing. Cold silicon (both microstrip and edgeless diodes), 3D detectors and microstations are being evaluated for this region.

Given the limited resources, both in terms of manpower and funds available within the TOTEM Collaboration, the LHCC recommends that TOTEM continue with the development of their experimental apparatus by concentrating on building a detector capable of meeting the approved goals of the TOTEM Technical Proposal while fitting-in to the CMS and LHC Machine environments. The detector, together with a description of the various responsibilities, schedules, costs and funding, are to be presented in the TOTEM Technical Design Report to be submitted to the LHCC by the end of 2003, namely with a one-year delay on the original date of submission.

 

8. TEST BEAMS

The SPS and PS Coordinator reported on the test beams.

He presented the first drafts of the SPS and PS East Hall user schedules for 2003. He noted that beam time is still available at the latter. The differing requests for the PS East Hall T9 area from ALICE (TPC beam tests), MICE (Muon Induced Cooling Experiment for their TPC beam tests), LHCb (storage and assembly space) and ATLAS (storage space for production muon chambers) need to be resolved soon. Following some cuts in requests for proton beam-time at the SPS, no major outstanding problems exist for the proton run. However, conflicts between NA49, NA57 and NA45 and the LHC experiments ALICE and CMS for use of the Indium heavy-ion beam were noted. The Research Board will decide on the heavy-ion programme in February 2003.

Finally, he reported on the structure in the new Accelerators & Beams Division and the consequences of the restructuring for the test beams. Due to the reduction in the number of staff and the on-call service, together with eliminating the dedicated secondary beamline operators, a slower response in case of problems is to be expected.

9.    LHCb COMPREHENSIVE REVIEW

The first of the LHCC Comprehensive Reviews of LHCb took place on 27-28 January 2003. The LHCC referees addressed the following areas: Vertex Locator and Inner Tracker, Outer Tracker, RICH Detectors, Calorimeters, Muon System, Tracking Performance, Trigger, Computing and Software, Physics Performance and the topics of Management, Technical Coordination, Integration, Schedules and Costs.

Since the approval of the Technical Proposal in 1998, the LHCb Collaboration has made very significant progress towards the realisation of an experimental set-up ready to record proton-proton collisions at the LHC and the LHCC expects LHCb to have a working detector installed in time for the beginning of LHC operation in April 2007.

In particular, all detector technologies to be used, except for the RICH photodetector, the TT station, the inner part of the M1 muon chamber and the full-length Outer Tracker, have successfully gone through the R&D phase and construction of the final components has either started or is imminent.

The re-optimisation of the LHCb detector has led to a more elegant experiment and with the same physics performance as specified in the Technical Proposal. The LHCC awaits submission of the LHCb Re-optimisation Technical Design Report and related Trigger Technical Design Report in September 2003.

The LHCC noted as a major concern the delay in the choice of photodetector for the RICH. The Committee encourages focused studies of the Hybrid Photo-Diode (HPD) and Multi-Anode Photomultiplier (MAPMT) options with the aim of the final decision to be taken in September 2003.

The principal conclusions and concerns of the LHCC are summarised below. They will allow the Committee to follow up the outstanding issues and to monitor future progress of this project in forthcoming sessions of the LHCC prior to the next LHCb Comprehensive Review one year hence.

§   Good progress was reported on the Vertex Locator (VELO). The LHCC considers that the interface of the VELO secondary vacuum to that of the LHC machine is the most critical issue but is being handled satisfactorily. The LHCC recommended general approval of the Inner Tracker Technical Design Report. Although the Committee has no major concerns, it noted that the signal-to-noise ratio of the long ladders is marginal and that also the physics performance will be re-visited in view of the LHCb detector re-optimisation.

§     The LHCC noted that the Outer Tracker has been reduced to three stations in the re-optimised LHCb set-up. Preparation for production of the chambers and the read-out electronics is progressing well. Certain further studies related to the evaluation of the full-length chambers and the detector’s ageing characteristics remain outstanding.

§ The RICH detectors are progressing well. Re-engineering of the RICH-1 detector is approaching completion. The major concern remains the delay in the choice of photodetector. The Committee encourages focused studies of the Hybrid Photo-Diode (HPD) and Multi-Anode Photomultiplier (MAPMT) options with the aim of the final decision to be taken in September 2003.

§    No major concerns were raised for the LHCb calorimeters. Construction of the ECAL and HCAL calorimeters is progressing well and the start of the SPD and PS construction is imminent. Although the electronics schedule is tighter, the main components are close to their final design and have already undergone extensive prototyping.

§     The LHCC recommended general approval of the Addendum to the Muon System Technical Design Report. The Muon System is moving into its production phase, albeit with a tight production schedule. The choice between Triple GEM and MWPCs for the inner regions of the first muon station M1 will be made in the summer 2003.

§    The LHCC noted the impressive progress made in recent months in studying the tracking performance of the re-optimised LHCb detector. The tracking resolutions (vertex, proper time and mass resolutions), together with the overall physics potential are similar to those described in the Technical Proposal, but with the results having been obtained with a more realistic Monte Carlo.

§     The particle identification performance of the RICH, Muon System and Calorimeters, with the exception of an increase in the pion misidentification which must be optimized further, is comparable to that quoted in the respective Technical Design Reports and satisfy the requirements of LHCb.

§       The trigger system is considered vital to the success of the LHCb experiment. Although the first studies of the trigger are encouraging, further detailed work is in progress leading up to the submission of the Trigger Technical Design Report in September 2003.

§       Good progress was reported on the LHCb Online System. In addition, the Committee noted the carefully designed software framework and the provision of common components and tools, developed in part with EP Division and the LCG, for the offline software. Migration of the software to C++, as well as event Monte Carlo production and the Data Challenges, are well-underway.

§    Although the physics performance study is still preliminary, event yields indicate that the physics aims given in the Technical Proposal will be met with the re-optimised LHCb detector. Further work is needed to complete the physics assessment and should include a detailed evaluation of systematic uncertainties.

§       The LHCC considers that although a significant amount of work lies in front of the experiment, it is realistic to expect LHCb to have a working detector installed in time for the beginning of LHC operation in April 2007. The LHCC also noted that the LHC Machine schedule has implications to the LHCb detector installation and the issue will be followed up in the March 2003 LHCC Installation Review.

 

10. LHCb ADDENDUM TO THE MUON SYSTEM TECHNICAL DESIGN REPORT

The LHCC completed its scientific and technical evaluation of the LHCb Addendum to the Muon System Technical Design Report. The Committee was impressed by the quality of the work presented in the Addendum to the Technical Design Report and congratulates the Collaboration. The Committee finds the MWPC detector technology proposed for the muon chambers adequate to achieve the physics goals stated in the Technical Proposal.

The Committee has no major concerns. An ancillary document (LHCC 2003-008) 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 LHCb follow the established practice of conducting independent reviews of the engineering designs. Written reports should be made available to the LHCC through its referees.

Recommendation

The LHCC recommends general approval of the LHCb Addendum to the Muon System Technical Design Report pending a final cost evaluation. The LHCC considers that the schedule given in the Addendum and the list of milestones in the ancillary document to be reasonable. They will be used by the Committee to measure and regulate future progress of the project.

 

11.   LHCb INNER TRACKER TECHNICAL DESIGN REPORT

The LHCC completed its scientific and technical evaluation of the LHCb Inner Tracker Technical Design Report. The Committee was impressed by the quality of the work presented in the Technical Design Report and congratulates the Collaboration. The Committee finds the detector technology proposed for the Inner Tracker adequate to achieve the physics goals stated in the Technical Proposal.

The LHCb Collaboration is studying the re-optimisation of the LHCb detector and this study could affect the Inner Tracker. The Inner Tracker is part of an integrated tracking system that includes the Outer Tracker. The LHCb Collaboration intends to describe the integrated tracking system in the LHCb Detector Re-optimisation Technical Design Report to be submitted to the LHCC in September 2003.

Although the Committee had no major concerns, it noted that the signal-to-noise ratio of the long ladders is marginal and also that the physics performance will be re-visited in view of the LHCb detector re-optimisation. In addition, the LHCC noted that further R&D is needed for the Trigger Station (TT). The design of the TT should be finalised in time for the submission of the LHCb Detector Re-optimisation Technical Design Report in September 2003.

An ancillary document (LHCC 2003-009) 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 LHCb follow the established practice of conducting independent reviews of the engineering designs. Written reports should be made available to the LHCC through its referees.

Recommendation

The LHCC recommends general approval of the LHCb Inner Tracker Technical Design Report pending a final cost evaluation. The LHCC considers that the schedule given in the Technical Design Report and the list of milestones in the ancillary document to be reasonable. They will be used by the Committee to measure and regulate future progress of the project.

 

12. DATES FOR LHCC MEETINGS

Dates for 2003:

 

                    26-27 March

                    21-22 May

                    2-3 July

                    24-25 September

                    26-27 November

 

 

The LHCC received the following documents

·      ATLAS actions in response to the LHCC ATLAS Installation Review Report
(LHCC 2002-043/G021).*

·      Addendum to the Muon System Technical Design Report (LHCC 2003-002/
LHCb TDR 4 Add. 1).

·      Status of the LHCb Detector Reoptimization (LHCC 2003-003/G023).*

·      Restricted circulation

 

                                                                        Emmanuel Tsesmelis

                                                                E–mail:    LHCC.Secretary@CERN.CH

                                                                Tel. 78949, 164057

 

LHCC Secretariat:    Janet Grant (Bldg. 14/4-022) Tel. 73424

                                 janet.grant@CERN.CH