Minutes of the twelfth meeting on 12 September , 1994


The ISC Chairman, Achim Richter, first welcomed the new CERN Research Director, L. Foà, and
three new ISC members, D. Habs, H. Nifenecker and K.L. Thielemann, and called on H. Ravn, Isolde Technical group leader to present his progress report. This consisted of three topics: molten metal targets and their shock wave problems, performance of the on line laser ion source, and performance of the general purpose separator. Much progress has been made on the first two topics, but there were several questions about stability and intensity of the proton beam from the PS booster. These concerns were noted by the Chairman as a subject for further discussion in the closed meeting.

O. Tengblad, the ISOLDE Coordinator, then presented his report. There are now 45 approved experiments, 12 of which have been finished. A total of 795 shifts have been approved, 495 of which have been delivered. He also presented a preliminary schedule for the coming third period.

Presentations were made of the following proposals:

1. Nuclear, electrical and optical studies of hydrogen in semiconductors Konstanz - Berlin - Duisburg
     - Erlangen - Freiburg - Jena - Lisboa - Caen - Troitzk Collaboration); ISC 94-15/P65; D. Forkel.

2. Test of new PAC probes for hyperfine interaction studies at Isolde Lisboa - Berlin - CERN
    Collaboration); ISC 94-16/P66; J.G. Correia.

A status report and beamtime request was also presented on experiment IS333: Neutron-rich silver isotopes produced by a chemically selective laser ion-source Kernchemie Mainz - Russian Academy of Sciences Troitzk - Nuclear Chemistry Maryland - Isolde Collaboration); ISC 94-17/M4; K.-L. Kratz.


Present:  J.V. Allaby, B. Allardyce, J. Eades Secretary), L. Foà, D. Forkel-Wirth, D. Habs,
               R. Helbig, A. Mueller, H. Nifenecker, H. Ravn, A. Richter Chairman), K. Riisager,
               O. Tengblad, F. Thielemann, P. Van Duppen.

Apologies: E. Moya de Guerra

The minutes of the last meeting were approved, and the Chairman started the meeting with a discussion of the problems with the PSB proton beam mentioned above) and the ISOLDE control system, both of which involve the PS division.

These problems cause difficulties to some experiments, and result in a number of lost shifts and scheduling problems, especially when the PS booster must accommodate the lead-ion beam project. After some discussion, it was clear that action is needed to match CERN's limited resources to ISOLDE users' needs, and that enough advance warning must be given of possible lost shifts in experiments which are sensitive to rate and stability problems so that the Coordinator can reschedule when possible. L. Foà agreed to take the necessary action in conjunction with the leader of the PS division and will try to clarify the situation by the next ISC meeting. He pointed out that in any case the problems related to the lead-ion project are likely to be much less severe in future.

The Committee then discussed the open meeting presentations as follows:

ISC 94-15/P65: Nuclear, electrical and optical studies of hydrogen in semiconductors :

This complex solid state proposal, which covers several topics and includes many collaborating institutions requests a total of 54 shifts. Among the topics the Committee was particullarly impressed by the cadmium and arsenic studies. It was decided to recommend allocation of 30 shifts for the present, the collaboration being given some freedom in setting goals and priorities among the topics. More generally it was noted that P65 uses several large pieces of equipment and that the experimental hall is sometimes overfilled. Scheduling of the experiment will be contingent on finding a solution to these space problems, and all experimental teams are therefore asked to remove equipment which is not used in their current programmes.

ISC 94-16/P66: Test of new PAC probes for hyperfine interaction studies at Isolde :

Concerning P66, the Committee considered that the main interest of the proposal is more in the development of a new technique than the stated physics programme as is in fact clear from the title). It was decided to schedule a 10-shift test with the technically easier longer lived isotopes, without formal Research Board approval. If the test shows that the technique can form the basis of interesting physics,
a new proposal should then be presented.

IS333 ISC 94-17/M4): Neutron-rich silver isotopes produced by a chemically selective laser ion-source :

The Committee found that good use has been made of the time allocated, good physics results have been obtained, and that the collaboration is the leader in the field. The 15 shift request for further running time will therefore be recommended to the Research Board.

Other Business

In addition to the proposals discussed above the following document has been received:

Letter of Intent SPSLC 94-18/I 197). Neutron halo and antiproton - nucleus potential from antiprotonic X-rays.

The Committee took note of this letter of intent.

Concerning the II-VI semiconductor Workshop proposed at the last meeting, the Committee decided to hold this on Tuesday 6 December from 10h.30 i.e. following directly on from the next ISC meeting of 5/6 December).

The dates of the 1995 meetings were chosen as follows:

                                13/14 February

                                15 May

                                28/29 August

                                27/28 November

The next ISC Meeting is on December 5/6.