CERN. Geneva. ISOLDE and Neutron Time-of-Flight Experiments Committee

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CERN/INTC 2000-030INTC 425 May 2000ISOLDE AND NEUTRON TIME-OF-FLIGHTEXPERIMENTS COMMITTEE (INTC)Minutes of the Fourth meeting onMonday 15 May, 2000OPEN SESSIONThe Chairman opened the meeting with a few brief words of welcome. He also stressedthat since one nTOF and one ISOLDE proposal are already awaiting the committee's attention,and that four more are already expected for the September 25th meeting, the deadline forsubmission of proposals to this meeting will be advanced From Monday 4 to Friday1 September.M. Lindroos, PS technical coordinator for ISOLDE operations summarised the presenttechnical status of the ISOLDE  facility. He also recalled the organization and tasks of the variousPS groups and noted that J. Lettry (whose responsibility is ISOLDE targets and front ends)should be contacted for eventual questions concerning new radioactive beams and forcollaboration on target issues. T. Giles is the contact person for the HRS, now expected to beworking in low resolution (16000) mode from 11 September.Thomas Nilsson the ISOLDE physics coordinator, presented a brief summary of thestatus of the ISOLDE programme. About 5 weeks of running have been achieved since the year2000 startup. Some fine-tuning of the of the draft schedule has been necessary, but it is expectedthat most of the 380 shifts foreseen in the most recent version of the schedule for 2000 will bedelivered.E. Radermacher then presented a Status Report for the nTOF facility. Much of theequipment already has been installed or will be forthcoming in the next month. The scheduletherefore assumes that commissioning will begin between the middle and the end of June, withthe beam expected to be fully available for experimenters in August.Presentations were then made of the following proposals and progress reports:P90 Add. 1 (INTC 2000-011): Use of radioactive ion beams for bio-medical research.P34 Add. 3  (INTC 2000-023): Neutron-rich silver isotopes produced by a chemicallyselective laser ion-source (Status Report on experiment IS333 part III andRequest for Beam Time).P69 Add. 1 (INTC 2000-027): Enzymatic Mercury Detoxification: The Regular ProteinMerR - DNA Interaction and the Mercuric Ion Reductase MerA.P91 Add. 2 (INTC 2000-002): Further Measurements of the 7Be(p, g )8 B cross section withan implanted radioactive 7Be target and its implications for the solar-neutrino"puzzle".P118 (INTC 2000-006): Charge radius measurement of the halo nucleus 11Li.P120 (INTC 2000-010): Probing the structure of very neutron-rich nuclei in the sd-pfshell by combined delayed neutron and gamma spectroscopy.2P124 (INTC 2000-017): The importance of 22 Ne( a, n)25M g as s-process neutronsource and the s-process thermometer 151Sm.P127 (INTC 2000-022): Studies of electric dipole moments in the octupole collectiveregions of heavy Radiums and Bariums.P128 (INTC 2000-024): Beta-decay study of neutron-rich Tl, Pb, and Bi by means ofthe pulsed-release technique and resonant laser ionisation.P129 (INTC 2000-028): Precision mass measurements of argon isotopes.CLOSED SESSIONPresent  :  B.W. Allardyce, J. Aystö, C. Détraz, J-P. Delahaye (part time), J-P. Duraud,J. Eades (Secretary), H. Flocard (Chairman), P. Van Isacker, K-L. Kratz, ,M. Lindroos, T. Nilsson, H. Ravn, C. Rossi-Alvarez, J-P. Riunaud, B. Rubio,W. Scobel, R. Voss (for G. Goggi), P. Walker.Apologies   : W. David, K.P. Lieb, K. Langanke, E. Migneco.The minutes of the third meeting were first approved without change, and the committeeproceeded to discuss matters arising from it. The first of these was the nTOF Technical DesignReport(TDR). The external referee has summarised the points he made at the last meeting in theform of a written list of questions, to which the nTOF group has very recently replied. Whenvarious modifications to the TDR have been made and additional supporting documents havebeen presented on these questions (including safety-related issue) it is hoped that the TDR can beaccepted by the committee at the September meeting. The final evaluation of the document will bemade by the external referee in conjunction with one internal referee from the INTC. In addition,the internal referee will be in charge of conducting an evaluation of issues not addressed in theTDR, including the collimation of the neutron beam, the experimental hall, and the neutrondetection equipment.The committee noted that following a written request from Thomas RUF, SPS/PScoordinator, the situation concerning the way nTOF shifts will be scheduled has now beenclarified. Beam time requests for nTOF will be discussed between the ISOLDE coordinator andthe SPS/PS coordinator prior to the relevant INTC meeting. The ISOLDE coordinator willinform the INTC about any proton beam allocation issues arising from these discussions, andwill discuss the INTC's own recommendations once more with the SPS/PS coordinator beforethe following Research Board. Final details of allocations will be settled by the twocoordinators after Research Board approval has been given.During discussions of the ISOLDE backlog in the previous two meetings, a decision hadbeen postponed concerning REX-ISOLDE, commissioning of which contributes 150 shifts to the700-shift total. The spokesman has in the meantime informed the committee of REX-ISOLDE'sprogress, and has suggested that a reduced number of shifts corresponding to three weeks(63 shifts) now seems to be adequate. The committee accepted this new estimate, congratulatedthe team on its achievements so far, and asked the spokesman to present a progress report in oneof the remaining two meetings in 2000.Concerning the ISOLDE reports of T. Nilsson and M-Lindroos, the committee welcomedthe good news concerning the HRS (high resolution separator) which is now at the 16000resolution specified in the Audit, and congratulated PS division on its success in quicklymatching the high level of competence that was always a feature of the former ISOLDE technicalgroup.Concerning the nTOF status report, the committee noted that the commissioned beam isexpected in August, but saw no conflict with the September date by which adequate replies toquestions concerning the TDR have been requested.3The proposals and progress reports presented in the open session, were then discussed asfollows:P90 Add. 1: Use of radioactive ion beams for bio-medical research.The collaboration was thought by the external experts to have made a good case for theproposed continuation, which is clearly of high scientific quality. The 12-shift requestwill therefore be recommended to the Research Board.P34 Add. 3:  Neutron-rich silver isotopes produced by a chemically selective laser ion-source(Status Report on experiment IS333 part III and Request for Beam Time).After a short discussion it was agreed that the proposal is timely, technically solid, andthat the necessary competence exists with in the collaboration. The 30-shift request willtherefore be supported by the chairman at the Research Board.P69 Add. 1:  Enzymatic Mercury Detoxification: The Regular Protein MerR - DNA Interactionand the Mercuric Ion Reductase MerA.Expert opinion has been sought outside the committee for evaluating the merits of thisproposal. It was agreed to recommend to the Research Board that the 10-shifts for the testexperiment should be allocated. On the other hand, the collaboration lacks the expertisethat would guarantee to the INTC that the stated goal of understanding the Hgdetoxification mechanism can be achieved or at least approached from results of the realexperiment. After a progress report on these tests, the latter may also be supportedprovided the collaboration can find the appropriate support and additional members in thebiochemical field.P91 Add. 2: Further Measurements of the 7Be(p, g )8 B cross section with an implantedradioactive 7Be target and its implications for the solar-neutrino "puzzle".The committee supported the requested allocation of 6 shifts and recommends that theyshould be used specifically to explore the low-energy region. The committee recalled itsprevious suggestion concerning the backscattering problem (February 1998) that thecollaboration look into the possibility of using commercially available foils.P118: Charge radius measurement of the halo nucleus 11Li.The relevance of the proposed measurements on 8Li, 9Li and 11Li is clear. On the otherhand, because the technology is being stretched to the limit it was decided to recommendallocation of the 8 test shifts for 8Li and 9Li. A progress report showing success withthese isotopes should be presented before the actual 11Li experiment can be scheduled.P120: Probing the structure of very neutron-rich nuclei in the sd-pf shell by combined delayedneutron and gamma spectroscopy.Although it will be interesting to bring to ISOLDE an experiment with the CaenTONNERRE neutron detector, it was agreed that a better-focussed proposal in either theN=20 or the Z=20 regions would be better suited to the facilities offered by ISOLDE. Noshift allocation will therefore be made at the moment.P124: The importance of 22 Ne( a, n)25M g as s-process neutron source and the s-processthermo-meter 151Sm.The scientific case for this proposal seems to be well justified, although it was thoughtthat several technical questions remain concerning the background and other matters.Many of these questions will clearly depend on the results of P123 (Determination of theneutron fluence, the beam characteristics and the backgrounds at the CERN-PS TOFFacility) approved at the last meeting. This is in particular true concerning the number ofprotons that will be required to do the experiment, the beam request being presented in4weeks of running time. It was therefore decided to consider the experiment as pending,until a Memorandum is received showing whether the results of the overall performanceof the nTOF facility as revealed by P123 give suitable answers to these questions. Inaddition, the INTC would like to have some clarification concerning which of the manyauthors listed on the title page constitute the working basis of proposal P124.P127: Studies of electric dipole moments in the octupole collective regions of heavy Radiumsand Bariums.Measuring properties related to the spontaneous octupole deformation is of great interest.The INTC believes that there is a clear priority for the 229Th and 226Ra cases. Thecommittee therefore recommends that initially 24 shifts be allocated for these two cases.P128: Beta-decay study of neutron-rich Tl, Pb, and Bi by means of the pulsed-release techniqueand resonant laser ionisation.The proposed study of neutron-rich nuclei near Z=82 should be relevant forunderstanding nuclear structure at extreme isospin values and it was decided to allocate26 shifts for an initial exploration. If necessary, an addendum may be presented on thecompletion of these.P129: Precision mass measurements of argon isotopes.The well-written proposal on high precision mass measurements in argon isotopesinvolves a well-tried technique, and all the necessary expertise is clearly present in thecollaboration. The committee was therefore in favour of approving the 17 shiftsrequested.OTHER BUSINESSTwo new Letters of Intent have been received:I32: Doping Properties of Ferromagnetic Semiconductors investigated by the HyperfineInteraction of Implanted Radioisotopes.I33: Production of polarized radioactive beams with laser ion sources (Feasibility test).The production of polarised radioactive beams (I33) was thought to be sufficientlyinteresting for a feasibility test to be approved, subject to the coordinator being able to find timeamong his reserved shifts. The committee also took note of the interesting goals of I32 andencourages further studies.The next ISC meeting is on 25 September 2000.J. EadesINTC Secretary, Tel. 76 74273John.Eades@cern.chINTC Secretariat:  Monique Budel (Bldg. 14/4-022); Tel. 76 74270Monique.Budel@cern.ch

Minutes of the fourth meeting on Monday 15th May 2000

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