ISOLDE EXPERIMENTS COMMITTEE
 
Minutes for the twenty-first meeting on
 Monday, 12 May 1997
 

OPEN SESSION

After a few brief introductory remarks, the Chairman called the ISOLDE technical group leader, to report on progress. H. Ravn outlined the many jobs successfully completed during the 1997 shutdown period with particular reference to the beam development programme and the progress made on laser ion source development. On the negative side, he was obliged to report that manpower losses related to early retirements etc. had been severely compounded by failures of support on the part of various CERN divisions upon which the ISOLDE group relies heavily. These deficiencies are in services normally provided by the ECP and EST divisions, but a potentially even more serious situation may develop if also the LHC division finds itself unable to provide the promised support with vacuum hardware and software. H. Ravn agreed that these problems result from CERN's current obligation to save money on the personnel budget, but he pointed out that unless these cuts are compensated by outside contracts, the ISOLDE programme will sooner rather than later come to a stop. In the subsequent discussion, several comments gave voice to the serious concern of the ISOLDE community over the future of its experimental programme.
 

The ISOLDE coordinator then presented her report, describing installation work and equipment relocation in the experimental hall annexe, and presenting the schedule for 1997. Of the 630 shifts pending in the ISOLDE programme, 400 have been requested for 1997, but on account of the restrictions described above, only 200 of these can at present be allocated.
 

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

1. Proposal: Diffusion in intrinsic and highly doped III-V Semiconductors Münster - ISOLDE
    Collaboration); CERN/ISC 97-12/P89.

2. Proposal: Use of radioactive ion beams for bio-medical research Univ. of Geneva - Division of
    Nuclear Medicine - Department of Medical Biochemistry - Department of radiology - Kantonsspital
    Basle - Technical University Munich - St. George Cancer Centre/Australia); CERN/ISC 97-14/P90.
 

3. Surface and Interface studies with radioactive ions IS318) Berlin - CERN - Konstanz - Aarhus
    Collaboration); CERN/ISC 97-15/P29 Add.2.

4. Proposal: Measurement of Be7 cross sections with an implanted radioactive target and implications
    for the solar neutrino puzzle Weizmann Institute of Science/Rehovot - Intitute of Spectroscopy of
    the Russian Academy of Science/Troitzk - Johannes Gutenberg-Universität/Mainz - Haifa - ISOLDE
    Collaboration); CERN/ISC 97-17/P91.
 

CLOSED SESSION
 

Present: B.W. Allardyce, R. Ammerlaan, G. Bollen, J. Eades Secretary), D. Fick, H.Wenninger
             replacing L. Foà), D. Forkel-Wirth, D. Habs, E. Moya de Guerra, H.Nifenecker, K. Peach
             replacing G. Goggi), H. Ravn, A.Richter Chairman), G.Sletten, F-K. Thielemann.

Apologies: W. Gelletly

The minutes of the twentieth meeting were approved without change. K. Peach announced that he will in future represent G. Goggi at all ISC meetings.

In discussion of the technical group leader's report, the commmittee congratulated H.Ravn and the ISOLDE technical group on the success of all their recent efforts but especially on the remarkable progress connected with the laser ion source, which should open up new vistas in the experimental programme. On the other hand the inability of CERN to provide adequate support to ISOLDE was felt to be extremely serious. In particular it was pointed out that the 400 shift per year allocation was part of the Memorandum of Understanding between the ISOLDE group and the CERN management.
 

In reply H. Wenninger, speaking on behalf of the CERN management, agreed that the ISC was the correct forum for open discussion of these problems, and reiterated the determination of the management to support ISOLDE fully in the period before LHC becomes operational, during which the ISOLDE programme will constitute a large part of the CERN research programme. He noted that the problems seem to centre around the availability of four or five key people in the affected divisions. Consequently, a possible interim solution could be the one envisaged by H. Ravn, under which the missing manpower could be supplied via outside contracts. He thought that this would be possible but that in the longer term it would be necessary to fill the gaps by creating specific posts to be attached to the ISOLDE group. H.Wenninger and K. Peach will therefore attempt by July 1st to find resources for the interim solution and take the necessary initial steps for the longer term one.

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

P89:. Diffusion in intrinsic and highly doped III-V Semiconductors

It was generally agreed that the short 9 shift) experiment on diffusion in III-V semiconductors would be worthwhile and productive, since there are important potential applications of such work in domains such as optoelectronic devices, and since data of this kind is in any case rather rare in solid state physics. The experiment will therefore be recommended to the Research Board.

It was also pointed out that many experiments of a similar type to the one proposed in P89 should be feasible with commercially available isotopes at any implantation facility. With the ISOLDE programme under the severe pressure outlined elsewhere in these minutes, future experiments of this nature will only be accepted if it can be very clearly shown that they are not technically possible elsewhwere.

P90: Use of radioactive ion beams for bio-medical research

The proposal is clearly application-directed and some discussion took place on when, how and where an applications facility could be realised if the suggested programme is successful. Of the three main lines of investigation proposed, that concerning 153Sm and radio-lanthanides has already registered significant progress, while on the other hand the proposed 149Tb therapy seems to be in need of a much better-substantiated justification. The remaining study PET radionuclide biodistribution in vivo) should clearly go step by step, with an interim report or publication after the first experiments have been performed showing quantitative results on local organ and tumour doses in terms of PET isotope concentration. The committee will therefore recommend to the Research Board that 10 shifts be allocated for the 153Sm and radio-lanthanide experiments and five for initial PET studies.

Concerning the 149Tb experiments the committee felt that it was not clear how this form of radiotherapy will work as its success depends critically on such factors as the range of alpha particles in tissue, the distance of the alpha particle from the cell nucleus and the fact that the branching ratio of alpha-emission in Tb is only 17%. Further detailed justification therefore needs to be presented before a proper evaluation can be made.
 

P29 Add.2: Surface and Interface studies with radioactive ions IS318)

It was agreed that the proposed surface and interface studies with radioactive ions represents a very interesting continuation of studies in this complex field already carried out competently and productively by the same group. The 15-shift request will therefore be scheduled without further recourse to Research Board approval. However, it should be understood that future studies of this kind will have to be supported by a new proposal, rather than by addenda to the existing one.
 

P91: Measurement of Be7 cross sections with an implanted radioactive target and implications for the solar neutrino puzzle

Strongly based astrophysical arguments were presented for carrying out the proposed 7Bep,gamma) 8B cross-section measurement. It was neverthelesss realised that a considerable investment of effort would be required in making the 7Be target. Evidently, a crucial point is the necessity of increasing the efficiency of the laser ion source by a factor of 10-50. The proposal was therefore accepted on condition that a) this is achieved, and b) a progress report is presented in about one year that convinces the ISC that concomitant progress has been made in Israel on the actual performance of the cross-section measurement. At that time, the experiment may be formally recommended to the Research Board.

OTHER BUSINESS

The committee took note of five Letters of Intent:

-    Development of a chemically selective laser ion source for cadmium; ISC 97-16/I22;
     T.Kautzsch et al..)

-    Spectroscopy of 100-102Pd by means of electron conversion and gamma-gamma correlation
      measurements; ISC 97-18/I23;  P.Sona et al..)

-    Nuclear spectroscopy with copper isotopes of extreme N/Z ratios ISC 97-19/I24; D. Habs et al..)

-    Study of the Ce behaviour produced in an isobaric chain during lixiviation of waste glasses;
      ISC 97-20/I25; A. Chevalier et al..)

-    Parity Non-Conservation in Nuclei: The Case of 180mHf; N.J. Stone; ISC 97-21/I 26).

Of these it was clear that P26 is likely to require careful study by the committee in the circumstances of the current manpower limitations.

The dates of the remaining ISC meetings in 1997 are:

                   29-30 September

                   08-09 December.