CERN/LHCC 95-75

LHCC 20 rev.

28 November, 1995

LARGE HADRON COLLIDER COMMITTEE

Minutes of the twentieth meeting held on Thursday and Friday,
16-17 November 1995

CLOSED SESSION :

Present: J.J.Aubert*, W. Bartel*, J.Bernabeu, R.J.Cashmore, L.DiLella, C.Dionisi, P.J.Dornan, P.Duinker, J.Ellis, J.Engelen, L.Foa, U.Goerlach, A.Golutvin, D.Hartill, H.J.Hilke (representing G.Goggi), E.Iarocci (Chairman), P.Igo-Kemenes, K.Kajantie, C.Llewellyn Smith*, N.McCubbin, H.Montgomery, K.Potter, A.Schopper, A.Schwarz, D.M.Sendall (Secretary), M.Spiro, M. Turala, H.Wenninger*, D.O.Williams, G.Wormser.

*) Part time

Apologies: F.Eisele, L.R.Evans, K.Nishikawa, K.Schubert, S.Yamada

1. The Chairman and the Director-General welcomed the new members of the Committee. The minutes of the nineteenth LHCC meeting (LHCC 95-55 / LHCC 19) were approved without amendment.

2. C. Llewellyn Smith gave a brief summary of recent developments around the LHC project. A new version of the LHC design study is now available (CERN/AC/95-05) and the machine advisory committee has held a first meeting. First meetings of the resource review boards for ATLAS and CMS took place in October. Recommendations of the LHCC will be discussed at the December meeting of an enlarged Research Board with an extended agenda. Negotiations continue with non-member states on their possible contribution to the project.

3. ATLAS status report

P.Jenni gave a report on ATLAS studies of the dependence of performance on cost and resources, and the flexibility of the design to deal with unforeseen problems.

4. CMS status report

M.DellaNegra gave a report on CMS studies of the dependence of performance on cost and resources, and the flexibility of the design to deal with unforeseen problems.

5. REPORT FROM THE MAGNET ADVISORY GROUP

P.Lazeyras presented a report on the revised design of the ATLAS air toroids. He also summarised work on the CMS solenoid conductor.

6. REPORTS FROM THE ATLAS AND CMS REFEREES

The committee heard reports by the ATLAS and CMS referees.

7. DISCUSSION OF ATLAS AND CMS

The committee discussed the status and plans of the two collaborations in the light of the referees' reports, including the dependence of performance on cost and resources. As a result of these discussions, the committee agreed on recommendations to be sent to the Director General for consideration by the Research Board. A copy of these recommendations is attached to the minutes.

8. REPORT FROM THE LDRB

H.Tiecke summarised the discussions of the LDRB meeting of 7 November. On the R&D programme, status reports have been submitted by RD8, RD39 and RD43.

Status Reports of approved projects presented at the open session

RD-8: Proposal to develop GaAs detectors for physics at the LHC (LHCC 95-57)

H.Tiecke summarised the achievements of the collaboration so far. A variety of both microstrip and pixel prototypes are working, and three firms have successfully made both detector types. Detectors with 100% charge collection efficiency are produced. Performance is very similar to silicon detectors, the same electronics is used and operation at low temperature does not cause problems. The LDRB drew attention to a few remaining areas of concern. A continued effort is required to understand the process which determines the charge collection efficiency. Preliminary data on pion and proton irradiation show a strong decrease in charge collection efficiency. Since these detectors are a baseline option for ATLAS, further study is required.

Following the advice of the LDRB, the LHCC recommends the continuation of the project for one more year (at minimal cost) with the following milestones:

- Study radiation damage in more detail, also at low dose.

- Understand the origin of the damage (in bulk or in the junctions).

RD-39: Development of superconducting microstrip detectors (LHCC 95-63).

H.Tiecke reviewed the history of the project and progress towards the goals for the past year. The collaboration is small and is partly committed to other experiments. Despite problems with wafer production, the collaboration is confident that a next generation of wafers produced with the same masks will reach the required current density. The LDRB therefore recommends a second iteration for wafer production, so that the collaboration can demonstrate that detection of charged particles is possible with this detector type. However the LDRB does not consider that this justifies an increase in manpower as requested in the Status Report. It is also understood that the cost will be small.

In agreement with this advice, the LHCC recommends the continuation of the project for one more year (at minimal cost) with the following milestones:

- Produce a new wafer with existing masks.

- Demonstrate that the principle works (with minor modifications to test equipment).

Reports on other projects

RD-42: Development of Diamond Tracking Detectors for High Luminosity Experiments at the LHC.

On the request of the LHCC the collaboration had submitted an addendum to their Status Report (LHCC 95-58), to clarify their plans on working with pixels. Presently available electronics cannot yet deal properly with small signals. The understanding of pixel related problems, such as edge effects and charge sharing, is under study within the collaboration.

Following the advice of the LDRB, the LHCC recommends the continuation of the project for one more year with the following milestones:

- Continue optimisation of the Chemical Vapour Deposition (CVD) process to

a) increase charge collection distance,

b) obtain larger area detectors for tracking,

c) understand pixel related problems (edge effects, etc.)

- Demonstrate radiation resistance against neutrons up to 10**15 /cm2

- Increase pion/proton dose to 10**15 /cm2

- Encourage some optimisation of existing readout electronics (use RD20 as a start).

RD-43: Research and development of a hadron calorimeter for high magnetic fields

No written status report was submitted, and the work within RD43 is now fully embedded in the CMS programme. The LDRB therefore considers the RD43 project as such to be finished, and the work will in future be covered by the LHCC referees.

The LHCC agreed with these conclusions.

Further discussions had taken place of work on Resistive Plate Chambers by ATLAS and CMS. This has resulted in a list of comments and questions which will be sent to the collaborations and to the LHCC Chairman and referees.

9. REPORT FROM THE LERB

F.Bourgeois reported on the first workshop on electronics for LHC experiments held in Lisbon in September. He summarised the aims and format of the workshop, which had been well attended and of a high standard. Notes on the panel discussions are now available (LHCC 95-72). F.Bourgeois summarised the views of the LERB on the topics covered in the various sessions.

On the R&D programme, a status report has been submitted by RD23

Status Reports of approved projects presented at the open session

RD-23: Optoelectronic analogue signal transfer for LHC detectors (LHCC 95-61)

F.Bourgeois gave an overview of the achievements of the project. Despite a number of technical problems the project is progressing well with clear plans for the coming year. Following the advice of the LERB, the LHCC recommends the continuation of the project for one more year (at minimal cost) with the following milestones:

- Link performance assessment

6 transmitters and 2 digital receivers demonstrator

- Technology assessment

Asymmetric Fabry-Perot Modulator (AFPM) growth

AFPM 8 channel package

compact hybrid transceiver

- Cost assessment

The LERB drew attention to the need for a review of the optical links under consideration for data transfer between the on-detector electronics and the first readout level of the data acquisition system. The LHCC took note of the need for such a review.

10. REPORT FROM THE LCRB

J.Harvey summarised the discussions of the LDRB meeting of 7-8 November. On the R&D programme, status reports have been submitted by RD41 and RD44.

Status Reports of approved projects presented at the open session

RD-41: Object oriented approach to software development for LHC experiments (LHCC 95-60)

J.Harvey gave an overview of the goals of the project, the achievements relative to the milestones, and current plans. Following the advice of the LCRB, the LHCC recommends the continuation of the project for one more year with the following milestones:

- Establish detailed and quantitative criteria for the assessment of project management techniques, Object Oriented methods, languages and tools; apply these evaluation criteria to those products studied as part of the RD41 project.

- Based on the experience obtained in developing the prototypes of the ATLAS and CMS reconstruction tasks, make a critical assessment of the advantages and disadvantages of using the Object Oriented approach for the development of reconstruction software for HEP experiments.

RD-44: GEANT 4: an Object-Oriented toolkit for simulation in HEP (LHCC 95-70)

J.Harvey gave an overview of the successes of the project, which had achieved the milestones set at the time of approval; he then reviewed some current issues. Following the advice of the LCRB, the LHCC recommends the continuation of the project for one more year with the following milestone (to be reached by early 1997):

- Release a first version of GEANT4 with geometry, tracking and electromagnetic physics at least equivalent to GEANT3 for the simulation of events in LHC detectors.

The LCRB also considers that a version with high energy hadronic physics should be released as soon as possible in 1997, and that user support for the first version of GEANT4 should be limited to physicists collaborating closely with RD44 on the evaluation and testing of the release.

The LHCC agreed with these conclusions.

RD-45: A Persistent Object Manager for HEP

J.Harvey gave an overview of the successes of the project to date and outlined some current problems. This was an interim report as requested by the DRDC at the time of approval. The DRDC had set as a first milestone to be completed after 6 months: "a requirements specification for the management of persistent objects typical of HEP data together with criteria for evaluating potential implementations".

The LCRB accepts that for this milestone, input from the ATLAS and CMS computing models is required, and it therefore cannot be met until late 1996. However progress made by RD45 can be very useful as input to the process of designing the computing models.

Therefore the following complement to the first milestone is proposed:

- Produce a statement of probable capabilities for an HEP persistent object management system based on commercial Object Oriented Database Management Systems and large-market mass storage systems.

The LHCC agreed with these conclusions.

Proposal presented at the previous meeting

P-61: High energy physics processing using commodity components (LHCC 95-46/P61)

J.Harvey gave an overview of the goals and motivation of the project, noting that very little resources had been requested.

The LCRB believes that the possibility of building batch processor farms with commodity components such as PCs and Windows NT has great potential, and is of great interest for the HEP community. However, it felt that the rather general description of the work programme contained in the proposal did not provide enough information for a complete evaluation of the project.

The LCRB therefore proposes to invite the P61 collaboration to provide an addendum containing this additional information, such that a final recommendation can be made at the time of the next meeting in January 1996.

The LHCC agreed with these conclusions.

Reports on other projects

RD-38: CICERO: control information system concepts based on encapsulated real-time objects

J.Harvey also reported on discussions of RD38. In view of the comments of the LHCC in March (LHCC 95-23) the LCRB had asked the referee to monitor progress and make a report. A response had also been received from ATLAS and CMS expressing their concerns. The reactions of the LCRB to this are set out in a memorandum to the LHCC Chairman (LHCC 95-80).

In view of this, the LCRB recommends that the RD38 project should be brought to a conclusion, and that members of the RD38 team should be encouraged to become involved in the slow control activities of the LHC collaborations. The generic slow control expertise gained in RD38 should now be transferred into activities specific to LHC.

Given the large amount of industrial collaboration which exists, an orderly wind-down of the project is essential. The LCRB therefore recommends that the RD38 project, through the appropriate management of the participating institutions, ensures that the existing commitments to industrial collaborators are brought to completion by the time of the final status report (anticipated in March 1996)

The LHCC agreed with these conclusions.

The LCRB also informed the LHCC that slow controls were foreseen to be an area for common projects, and suggests that this issue should be considered when a first iteration of the individual detector requirements is available.

The LHCC took note of these views.

11. REPORT FROM THE LHC-B REFEREES

The committee heard a report from the LHC-B referees covering physics performance, organisation, and responses to the requests formulated at the September meeting of the LHCC. Preliminary reactions from CORE and the LERB and LCRB were presented.

Based on the LHC-B Letter of Intent, the LHCC will be pleased to recommend that the collaboration should proceed to a technical proposal following receipt of an acceptable plan, with agreed milestones, for the R & D necessary to prove the viability of the experiment. The schedule for the technical proposal will be set when the feasibility of the critical elements, particularly the particle identification and trigger / DAQ, has been successfully demonstrated.

12. TEST BEAMS

A.Schopper summarised the expected situation for 1996, where a number of scheduling problems remain to be resolved and to be discussed in the SPSLC. ATLAS, CMS and ALICE have made first estimates of their longer-term requirements (LHCC 95-59, 95-67, 95-69). These show a potential overload of test beam facilities, and will need further discussion with the referees.

13. REFEREES

Following the changes of LHCC membership, the referees are now as follows:

ALICE: U.Goerlach, N.McCubbin

ATLAS: A.Golutvin, P.Igo-Kemenes, H.Montgomery (Co-ordinator), M.Spiro, A.Schwarz

CMS: R.J.Cashmore (Co-ordinator), C.Dionisi, L.Di Lella, J.Engelen, G.Wormser

LHC-B: J.Bernabeu, P.J.Dornan (Co-ordinator), J.Ellis, D.Hartill

14. DATES FOR 1996 MEETINGS

1-2 February

28-29 March

30-31 May

4-5 July

29-30 August

31 October - 1 November