LARGE HADRON COLLIDER COMMITTEE
Minutes of the forty-fourth meeting held on
Wednesday and Thursday, 26-27 January 2000
1. Status of the LHC project: L. Maiani
2. RD42 status report (LHCC 2000-011): P. Weilhammer
3. RD39 status report (LHCC 2000-010): V. Palmieri
4. ALICE TPC TDR (LHCC 2000-001 / ALICE TDR 7): P. Braun-Munziger
5. ATLAS status report: P. Jenni
Apologies: W. Bartel, J. May, M. Mazzucato
The Chairman informed the LHCC that the Research Board, at its 143rd Meeting on 18 November 1999, approved the ALICE TDR on their Dimuon Forward Spectrometer, pending a final cost evaluation and under the LHCC formulation which allows the Committee to monitor future progress. Moreover, the Research Board concurred with the decisions of the LHCC concerning the measurement programme of TOTEM and the preparation of a TDR by TOTEM. The TDR should address the design of their detector and should take account of the agreement between CMS and TOTEM.
The minutes of the forty-third LHCC meeting (LHCC 99-38 / LHCC 43) were approved with the following modification: in point 5 (report from the LHCb referees) the second sentence should be replaced by: `The two options are Hybrid Photodiodes (HPDs) and Photomultipliers (PMTs). Originally, no commercial devices satisfying the RICH requirements were available, leading the LHCb collaboration to initiate an R&D programme with vendors.'
2. REPORT FROM THE ALICE REFEREES
The Committee heard a report from the ALICE referees, concentrating on the review of the TDR for the Photon Multiplicity Detector, which was performed with U. Heinz as consultant. The detector will measure the multiplicity and spatial distribution of photons and will aid in the estimation of the transverse electromagnetic energy, all on an event-by-event basis. These measurements will facilitate the study of chiral symmetry restoration, of the deconfinement transition and of matter under extreme conditions.
The referees also reported on their preliminary reactions to 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. 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 Strip Detector and the Dimuon Forward Spectrometer.
The referees also presented a status report on the ALICE TOF system. The TDR will be submitted in March and presented to the LHCC at its May session.
W. Bartel has provided a cost evaluation of the ALICE Dimuon Forward Spectrometer, the conclusions of which show that the cost estimates reported in the TDR are considered to be reasonable.
3. REPORT FROM THE ATLAS REFEREES
The Committee heard a report from the ATLAS referees, including a review of the overall schedule. The referees consider that there is steady technical progress, overseen by an excellent team. Sound procedures are operational to track the progress, but delays in various sub-systems have been reported with respect to the baseline schedules in the TDRs. These delays are of concern as they make the production schedules for some sub-systems tight.
The referees also reported on their recent overall review of the calorimeters. The schedule for the LAr calorimeter must be updated once the production process is well-advanced. The Tile calorimeter is considered to be progressing on schedule.
4. REPORT FROM THE CMS REFEREES
The Committee heard a report from the CMS referees. The current status of various milestones was reviewed.
The referees also reported on the decision concerning the lay-out and the technology of the Tracker. Both the barrel and forward MSGCs, to be used as the outer tracker detectors, passed their milestone test at PSI at the end of 1999. The alternative option of an all-silicon Tracker continued to be studied in parallel. Results from the MSGC test programme and from the study of the all-silicon Tracker were available for a decision to be made by CMS during the previous two months. CMS has chosen the all-silicon option. This choice leads to a uniform technology and it is considered that such a Tracker will be simpler in many system aspects. Moreover, the reduction in costs of silicon and the associated electronics appears to make such a choice financially feasible. The all-silicon Tracker differs drastically from that presented in the original CMS Tracker TDR (LHCC 98-6) and an addendum to this TDR, detailing the new design and addressing issues such as the schedule and milestones, cost and manpower, is required. This addendum will be submitted to and reviewed by the LHCC in the usual manner.
The referees also reviewed the CMS HCAL, for which very good progress was reported. All mechanical and optical components of the barrel (HB) and end-cap (HE) calorimeters are considered to be advancing well. However, the referees expressed some concern over delays in the design and production of the HCAL front-end electronics.
5. ALICE PHOTON MULTIPLICITY DETECTOR TECHNICAL DESIGN REPORT
The LHCC has completed its scientific, technical, and initial cost evaluation of the ALICE Photon Multiplicity Detector TDR submitted in September 1999. The Committee was impressed by the quality of the work presented in the TDR and congratulates the collaboration. The TDR describes a photon preshower detector whose technology and design are well-suited for the detection of photons in the high multiplicity environment of ALICE.
The Committee has no major concerns. An ancillary document (LHCC 2000-013) 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 Photon Multiplicity Detector Technical Design Report, pending a final cost evaluation. 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 LHCb REFEREES
The Committee heard a report from the LHCb referees, including a presentation of the general status, the tracking of LHCb technical decisions by the LHCC referees, and the TDR schedule for 2000.
The referees also reported on their preliminary reactions to the TDR of the LHCb Magnet. The Committee considers that the TDR describes a resistive magnet which is robust, cost-effective and which is well-adapted to the experiment and encourages the collaboration to continue developing the design. The Magnet Advisory Group (MAG) fully endorses the design concept and will provide a detailed report to the next session of the LHCC.
The referees also reported on the decision regarding the RICH photon detector. The three options considered were a pad HPD, a pixel HPD and a Hamamatsu MultiAnode PMT. A thorough procedure was followed involving the evaluation of each option on the criteria of physics performance, cost and risk. Following a detailed consideration, the pixel HPD was chosen as the baseline with the MultiAnode PMT serving as a back-up solution. Milestones were set for the pixel HPD, which should be passed by the end of the year in order for this option to remain the baseline. Further developments on the PMT back-up solution will continue in parallel.
7. REPORT FROM THE RD42 REFEREE
The Committee heard a report from the RD42 referee on the collaboration's programme regarding the development of intrinsically radiation-hard CVD diamond tracking detectors. The referee summarized the progress of work and the interest for such detectors at the LHC. This R&D project was expected to be completed by the end of 1999. Progress, in particular on series production of sensor material, has been slower than expected. Good quality CVD diamond can now, however, be routinely produced and the manufacturer will meet with interested parties at CERN in March 2000.
The referee recommends that the R&D project should be completed during 2000 with particular emphasis on beam tests of existing pixel detectors equipped with electronics adequate for LHC experiments. A final status report should thereafter be submitted to the LHCC. The Committee agrees to the continuation of the project on this basis.
8. 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 liquid nitrogen temperatures. The referee summarized the operation principles of irradiated and non-irradiated silicon detectors, the interest of the LHC machine and experiments in the techniques being developed by RD39, recent encouraging test beam results and plans for further work.
Symmetric Al/p+/n/p+/Al implanted silicon detectors, operated at 130 K, exhibit very good position resolution and radiation hardness at 1015 n/cm2. RD39 has also shown that low-mass liquid nitrogen cooling is feasible.
The referee recommends that the collaboration should carry out their proposed further programme of work and report again to the LHCC. The Committee agrees to the continuation of the project on this basis.
9. TEST BEAMS
T. Ruf showed the 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. The former two schedules have been discussed and agreed with the users, while the LPI schedule will be discussed at the beginning of February. He also mentioned that a discussion for reducing the SPS energy during 2000 from 450 GeV to 400 GeV is in progress.
10. ANY OTHER BUSINESS
The Chairman reminded the Committee that a change to the reviewing procedure of the LHCC is being discussed, with the aim of introducing periodic reviews of the experiments in their entirety and of facilitating the exchange of knowledge and experience between the referee teams.
The Director of Research for Collider Programmes thanked B. Kephart, who is retiring as member of the LHCC, for his vital role in defining the LHC experimental programme and for coordinating the LHCC refereeing activities for ATLAS.
11. DATES FOR 2000 MEETINGS
8- 9 March
5- 6 July