CERN/LHCC 93-37

LHCC 7

16 June, 1993

LARGE HADRON COLLIDER COMMITTEE

Minutes of the seventh meeting held on Tuesday and Wednesday, 8-9 June 1993

Present: J.V. Allaby, J.J. Aubert (Chairman), F. Brasse (for point 2), G. Brianti, R.J. Cashmore, L. Di Lella, P.J. Dornan, P. Duinker, K. Einsweiler, F. Eisele, J. Ellis, E. Fernandez**, L. Foa, W. Hoogland, E. Iarocci*, P.G. Innocenti, K. Kajantie, V. Khovansky**, L. Leistam (for point 3), C. Llewellyn Smith, G.W. London, G. Mikenberg**, K. Potter, K. Pretzl**, K. Schubert, D.M. Sendall (Secretary), H. Wenninger (for point 3), D.O. Williams

*) Part time **) Absent for point 4

Apologies: L. Maiani, C. Rubbia, S. Yamada

CLOSED SESSION :

1. The minutes of the sixth LHCC meeting (LHCC 93-33 / LHCC 6) were approved without amendment.

2. COSTS REVIEW GROUP

F. Brasse gave a status report on the work of the group. CORE had received two official comments on their first report: one from RD2 concerning the costs of silicon strip detectors, and one from ATLAS with a correction to the manpower estimate for the accordion calorimeter.

F. Brasse summarised the status of their work with the ALICE collaboration. Detailed realistic estimates existed for most subdetectors, and CORE had not discovered any major area of disagreement. There was some concern about the problem of data storage. Overall cost estimates had been made on the basis of two scenarios, one based on the L3 magnet, and the other with a new magnet. More information and discussions are needed.

3. EXPERIMENTAL AREAS

K. Potter reported on possible use of experimental areas. He presented cost estimates with a breakdown into civil engineering, surface buildings, conventional services, and the intersection. Estimates were given for ATLAS at Points 1 and 7 with a new cavern, and for CMS in the existing Point 2 cavern or with a new similar cavern at Point 1 or 7. He also presented estimates for ALICE at Point 2 using the L3 magnet, and at another LEP area with a new magnet. Several possible overall scenarios for the three experiments were compared. The situation for specialised B experiments as presented at the 11-12 May workshop was reviewed.

The substantial cost of surface buildings was discussed. It was agreed that a different approach to assembly of the experiments might lead to savings in this area, and the collaborations are encouraged to work closely with the experimental areas group on a cost optimisation. The possibility of using an existing LEP area such as Point 6 for ATLAS or CMS was also raised. It seems unlikely that this could lead to significant savings.

4. DISCUSSION OF ATLAS

F.Eisele reported on the work of the ATLAS referees. Recent discussions with the collaboration had concentrated on the muon system, tracking, and software plans.

The committee had extensive discussions of ATLAS, and the steps that would be necessary to move towards a technical proposal. As a result of these discussions, the committee decided to recommend provisionally that ATLAS should proceed to a technical proposal, and agreed on milestones for a further review in November 1993 to be sent to the Director General for consideration by the Research Board. A copy of these is attached to the minutes (LHCC 93-41).

5. DISCUSSION OF CMS

L. Foa discussed the CMS paper on milestones (LHCC 93-36 rev.), written in answer to a number of questions from the Chairman.

The committee had extensive discussions of CMS, and the steps that would be necessary to move towards a technical proposal. As a result of these discussions, the committee decided to recommend provisionally that CMS should proceed to a technical proposal, and agreed on milestones for a further review in November 1993 to be sent to the Director General for consideration by the Research Board. A copy of these is attached to the minutes (LHCC 93-41).

6. GUIDELINES FOR TECHNICAL PROPOSALS

The committee agreed on a list of points to be covered by the technical proposals. A copy of these is attached to the minutes (LHCC 93-41).

7. HEAVY IONS

G. Brianti gave a brief presentation of recent work on lead ions for the LHC using the LEAR ring as an accumulator. It was estimated that at a modest cost luminosities of about 10**27cm-2s-1 could be reached for Pb-Pb collisions with a single experiment. A technical report will be available shortly.

The committee heard a first report from the ALICE referees (K. Kajantie, G. London, K. Pretzl). The physics interest of Pb-Pb collisions was outlined, and the prospects for LHC compared with present and planned experimental programmes at CERN and RHIC. It was suggested that the committee needed more information on the RHIC programme. The ALICE strategy and feasibility issues were summarised. It is clear that a substantial R&D effort will be needed.

In the subsequent discussion a number of questions was raised which the referees will take up with the collaboration. The committee felt that colour screening was an interesting and important area for investigation.

8. B PHYSICS

K. Schubert summarised the situation after the B physics workshop of 11-12 May. He concluded that B physics would be a vital part of the LHC experimental programme. ATLAS and CMS can do B physics, but their capabilities are limited. The selection of a specialised experiment would necessarily be based on compromises between various factors: the three approaches presented at the workshop had made different choices. A number of points were proposed for consideration by the referees.

The date of 15 October 1993 had been decided for the submission of Letters of Intent, and guidelines have been sent to the spokesmen (LHCC 93-35). The following referees from the LHCC were nominated:

P. J. Dornan, J. Ellis, E. Fernandez

9. ACCELERATOR BACKGROUNDS

K. Einsweiler reported on recent work on accelerator backgrounds and effects on SSC detectors. Neutrons are largely produced from hadronic showers in the forward regions. Preliminary results were presented on simulated neutron and photon fluxes, energy spectra and detector response. Although first attempts to protect the muon system from these backgrounds look promising, the additional shielding material required may imply some reduction in muon system coverage. Further work is required.

10. TIMETABLE AND FUTURE MEETINGS

It was agreed that insufficient progress could be made on important questions before the planned LHCC meeting on 31 August - 1 September. The meeting is therefore cancelled. The 16-17 November meeting should include open presentations of B physics Letters of Intent, plus presentations of status reports by ATLAS and CMS at the closed session.

11. DATES FOR 1993 MEETINGS

16-17 November

The LHCC received the following documents:

o The CMS Collaboration: Milestones up to June 1994 (LHCC 93-36 rev.)

o LHCC magnet advisory group: Proposed milestones for the LHC experiments magnets (LHCC 93-38)

o B. De Raad: Safety of the LHC experiments (LHCC 93-40)

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MS, 21 July 1993