Minutes for the twenty-sixth meeting on
Monday 8 February 1999


After a few words of welcome to C. Détraz, CERN's Research Director from 1 January 1999, the Chairman invited the ISOLDE Technical Group Leader to present his report. H. Ravn used the opportunity to summarise those works being carried out during the present shutdown period that are of most interest to the community of ISOLDE users, devoting special attention to problems and solutions concerning the general purpose and high resolution separators, the beamlines and the REX-ISOLDE installation. He remarked that the cumulative effect over the last three years of cutbacks in funding and general support at CERN mean that only 200 eight-hour shifts will be available to users in 1999. This is to some extent offset by the fact that a board for the appointment of a mechanical engineer will take place on March 5, and that a vacancy notice for a fourth engineer has now been approved by CERN/EP.

Thomas Nilsson then presented the ISOLDE Coordinator's report and proposed 1999 schedule. He first noted that a post-shutdown separator course held in December had been well-attended and that a similar course had therefore been planned for March 1999. The above-mentioned shortfall in shifts 200 available against 300 that might technically be possible) was evident in the appearance of a period of several unscheduled weeks on the ISOLDE calendar for September and October. This is to be seen against a background of 38 approved experiments, which together have requested 460 shifts in 1999.

Presentations were then made of the following proposals and progress reports:

1. IS358: Magnetic Moment of 67Ni and 67Ni Æ 67Cu ß-Decay; J. Rikovska;
    ISC 99-6/P79 Add.1.

2. Mass measurements at ISOLDE with a Transmission RAdiofrequency spectrometer on-Line MISTRAL);
     D. Lunney;   ISC 99-3/P107 IS346).

3. Diffusion of Fluorine in high open porosity graphite; M. Menna; ISC 99-8/P108.


Present:      B.W. Allardyce, G.Bollen, C. Détraz, J. Eades Secretary), D.Habs, P. Van Isacker,
                  T. Nilsson, H. Ravn, A. Richter Chairman), G. Sletten, F.-K. Thielemann, R. Voss
                  for G. Goggi), P. Walker.

Apologies: R. Ammerlaan, D. Fick, K.-L. Kratz.

The Chairman welcomed again C. Détraz, the recently appointed CERN Research Director. The minutes of the twenty-fifth meeting were then approved after noting that "prolate-oblate deformation" should be substituted for "prolate-oblate separation" in the discussion of proposal P103.

In discussing the Technical Group Leader's and Coordinator's reports, the Committee noted with satisfaction the technical progress being made during the current shutdown, and the improvement in the situation that can be expected from the two new appointments. However, concern was expressed about the import of the decline in resources, manpower and services referred to by H. Ravn. The total of 200 available shifts for 1999 when 460 shifts have been requested is particularly worrisome. It was felt that a solution would have to be found by a concerted effort on the part of the technical group, the CERN Management and the ISOLDE collaboration Committee. C. Détraz stated that he felt it his duty to understand the origins of this problem fully, and to report it to the CERN Directorate. He remarked nevertheless that under the present circumstances, such difficult constraints are the rule rather than the exception in CERN research activities.

The Chairman drew the attention of the Committee to the possible approval by the Research Board of a new neutrino experiment LOI SPSC/I216) at the PS. This should run from 2001, and will certainly have an impact on the number of protons available for ISOLDE unless accompanied by careful management of machine resources. The CERN Management has realised this and will take the appropriate steps.

The closed meeting then continued with a discussion of the proposals and progress reports presented in the open session, as follows:

P79 Add.1: IS358: Magnetic Moment of 67Ni and 67Ni Æ 67Cu ß-Decay

The general feeling of the ISC was that previous experience of the collaboration in experiment IS358 has indicated that the most interesting of the magnetic moment studies discussed in the addendum are 69Cu and 71Cu, and that the requested 12 shifts should therefore be allocated for these high-priority cases, without further need for Research Board approval. On account of difficulties in interpreting the 59Cu case, it was felt that this measurement should not be perfomed. It was also thought that the collaboration of the two Russian physicists mentioned in the addendum would be essential for the successful operation of the laser ion source, and that the collaboration should therefore find ways of including them as fully active members.

P107: IS 346: Mass measurements at ISOLDE with a Transmission RAdiofrequency spectrometer on-Line MISTRAL)

The reaction of the Committee was in general very favourable to the proposal, which appears to be based on a solid foundation of successful operation of the MISTRAL spectrometer. Indeed the best results obtained so far indeed call for rapid publication and the Committee urges that this be done. The proposed new measurements in the N=20 and N=28 region using hot plasma ion- as well as surface ionization- sources will clearly benefit from consultation with groups making similar measurements elsewhere at lower precision e.g. GANIL). This should enable MISTRAL to select candidates for study on the basis of timeliness and usefulness. The Chairman will report to the Research Board that the Committee considered the total request of 36 shifts to be a reasonable target, but left the allocation of a suitable
first i.e. 1999) segment of this total to the discretion of the Coordinator. The collaboration will then be expected to present a progress report.

P108: Diffusion of Fluorine in high open porosity graphite

The virtue of the proposed implantation of 18Ne into graphite matrices was agreed to have been demonstrated The Committee also noted the relevance of P108 in developing the powerful fluorine beams which are required by other ISOLDE experiments. The collaboration is therefore invited to come to an arrangement with the Coordinator for scheduling the two shifts requested.


Concerning proposal P102 Self-Diffusion of Carbon and Nitrogen in the amorphous ceramics Si26C41N33 and related materials), which had been referred to an external referee after the November 1998 meeting, it was clear that a suitable case had been made for the proposed measurements. The Committee therefore will recommend to the Research Board that 21 of the requested 42 shifts should be initially allocated. These shifts should then form the subject of a progress report.

Concerning P80, Search for physics beyond the standard model via positron polarization measurements with polarized 17F) which has been the subject of a letter to the Chairman, the Committee agreed with the arguments presented for carrying out an experiment on 118Sb before the one with the 17F beam. It also welcomed the collaboration's offer of technical support on the latter. The Chairman has made this clear in a written reply to the spokesman.

The next ISC meeting is on 3-4 May 1999.