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

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CERN/ISTC 99-1ISTC 14 October 1999ISOLDE AND NEUTRON TIME-OF-FLIGHTEXPERIMENTS COMMITTEE (ISTC)Minutes of the first meeting onMonday 27th September, 1999OPEN SESSIONAfter a few words of welcome to the first meeting of the newly constitutedISTC committee, the ISTC Chairman Hubert Flocard paid tribute to his predecessor,Achim Richter, who for six years has fulfilled the post of ISC chairman with great distinctionand farsightedness. He then introduced the CERN Research Director, Claude Détraz, whoreviewed the new role and mandate of this new committee, which has been formed to examineand monitor the research programme of both the ISOLDE and (from April 1999) the neutronTime-Of-Flight (nTOF) facilities.C. Détraz outlined the new role of the ISTC as an extended committee to takeresponsibility for monitoring proposals concerning the overlapping fields of physics covered bythese two facilities. He pointed out that they will become key players in the CERN researchprogramme between 2000-2005. During this waiting period for the first LHC beams, CERN'sscientific activity will decrease for the first time in decades. This constitutes a difficult andcrucial period in the organisation's history, and the ISOLDE and nTOF programmes will play acorrespondingly greater role in the general perception of CERN in the member states andworldwide. C. Détraz thanked both old and new members of the committtee for assuming theirpart of this burden. He saw immediate tasks and difficulties confronting the ISTC on both theISOLDE and the nTOF side. The backlog of some 2 years of ISOLDE shifts must now beseriously addressed as well as the problem of bringing the High Resolution Separator, to its fullcapacity, and he suggested that the ISTC might profitably review priorities in both these matters.Concerning the nTOF side he stressed the difficulties of going from a project backed by anenthusiastic commmunity of physicists and by the CERN Research Board, to a facilityfunctioning on a day to day basis, the experimental programme of which must necessarily besubject to constant evaluation and review.N. Pavlopoulos then presented a general view of the nTOF facility, pointing out its currentthreefold aim as a research instrument for studies of stellar nucleosynthesis, nuclear technologyand dosimetry, and nuclear physics and the properties of the neutron. With a beam flux on targetof 2E1013 protons in a 24 GeV 6 ns pulse, this constitutes a prolific source of neutrons incomparison with other neutron facilites. These advantages are combined with low gamma andcharged particle backgrounds and a neutron energy resolution better than 1 percent over thewhole energy range from 1 eV to 250 MeV. A full technical design report will be presented tothe ISTC at a forthcoming meeting, together with proposals for evaluating the nTOF'sperformance.M. de Saint-Simon then presented a summary of the Audit report of the ISOLDE HighResolution Separator. This had been requested by the ISOLDE collaboration and was authoredby M. de Saint Simon himself and N. Severijns. He discussed the performance of the HRSa) in a "routine operation mode" without high order corrections, characterised by a typicalresolution M/D M = 6000,  andb) in a "high resolution mode", including high order corrections and with a massresolution of 15000, which would clearly be beneficial to many experiments.. 22The authors conclude that mode  a) should first become truly routine, and that b) which isalso strongly needed is indeed feasible. To implement these two steps, both technical andstructural components are needed. The technical ones are at hand, but the structural ones involvecareful planning, adequate technical support, a choice of priorities and clear definition ofresponsibilities.Three short status reports followed. H. Ravn, ISOLDE technical Group Leaderconcentrated on ISOLDE beam maintenance and development, with reference to the IS343 RISTtarget, which has improved the 11Li intensity by a factor of 10 to 30000/microCoulomb, and tothe booster energy increase to 1.4 GeV with a concomitant intensity increase from 3.3E13 to3.9E13 per pulse. The latter results in both gains and losses in the formation cross-sections, andtests with 600 MeV protons are planned. T. Nilsson presented the ISOLDE coordinator's reportand concluded that in spite of various technical problems, the original 1999 schedule had beenfollowed well, with the number of outstanding shifts being reduced by 115. FinallyE. Radermacher, nTOF technical group leader, briefly described the present status of the PSbeam, lead target and time of flight tube, the three parts making up the nTOF facility. Thepresent plan foresees that the installation work will be finished by April 2000.The closed meeting ended with a presentation of two new ISOLDE proposals:P113: Decay study for the very neutron-rich Sn nuclides, 135-140Sn separated by selective laserionization.P114: Investigation of the single particle structure of the neutron-rich sodium isotopes 27-31 Na.CLOSED    SESSION    Present:  B. Allardyce, J. Aystö, C. Détraz, J.-P. Duraud, J. Eades (Secretary), H. Flocard(Chairman), K.P. Lieb, T. Nilsson, H. Ravn, C. Rossi-Alvares, B. Rubio,G. Sletten, P. van Isacker, R. Voss, P. Walker.Apologies:  W. David, K.L. Kratz, E. Migneco, W. Scobel.The Chairman opened the meeting by welcoming new members of the committee, and theminutes of the last ISC meeting were approved without change.In discussing C. Détraz's presentation to the Open meeting, the committee's attention wasparticularly drawn to the ISOLDE backlog of shifts, which is at the moment large compared to atypical annual shift allocation. It was agreed that it is appropriate to respond to this situation bydevoting part of the November closed session to a closer look at the overall nature of thebacklogged experiments. It will be useful to know how they are distributed among those readyto take data, those having used up part but not all of their allocation, those waiting for REX-ISOLDE anyway, those not yet ready to take data, etc. The Chairman will therefore consult withthe ISOLDE coordinator, Thomas Nilsson, and assign various committee members to take acloser look at these several classes.The ISOLDE HRS Audit report by M. de Saint-Simon was received as one of the keys tounblocking the shift situation mentioned above. In view of this, the committee agreed that theISOLDE technical group should concentrate on realising the first HRS mode (routine operationat relatively low resolution) as soon as possible. H. Ravn estimated that 1 MY of manpowerwould be enough to achieve this goal in time for the next year of ISOLDE operation.Concerning the presentation of the nTOF facility, the committee was impressed by thequality of the scientific programme discussed and looks forward to seeing the technical proposalat an early date, and also to the presentation of proposals for evaluating the nTOF performance.The committee also took note of the status reports of H. Ravn, T. Nilsson and E. Radermacherwith satisfaction.. 33The committee then proceeded to discuss the two ISOLDE proposals presented in theOpen session:P113: Decay study for the very neutron-rich Sn nuclides, 135-140Sn separated by selective laserionization.After a short discussion the committee expressed a positive opinion concerning thisproposal. The proposed measurements of half-lives and delayed neutron branching ratios shouldgive worthwhile information on spectroscopy of very neutron rich nuclei and on astrophysicalr-process nucleosynthesis beyond N = 82. The Chairman will therefore recommend to theResearch Board the approval of the full requested allocation of 15 shifts.P114: Investigation of the single particle structure of the neutron-rich sodium isotopes 27-31 Na.The committee was positively impressed by the proposed investigation of the singleparticle structure in neutron-rich sodium isotopes. It was agreed that the inverse kinematictechnique via neutron pickup reactions was adequate and that the experiment would makeefficient use of REX-ISOLDE in studies of the region around Z = 12 and N = 20. Theexperiment falls into two clear parts. In view of the situation regarding allocations and of the factthat a study of the four lightest isotopes should provide a good indication of the potential of themethod the Chairman will for the moment recommend to the Research Board an initialallocation of the 12 shifts requested for the first part, after which the collaboration is encouragedto present a progress report.OTHER BUSINESS:The committee noted the appointment of Piet van Duppen as the successor toGerhard Huber as Chairman of the ISOLDE collaboration.The next ISTC meeting is on 29 November 1999.The dates of the 2000 meetings are:28 February15 May25 September27 NovemberJ. EadesISTC Secretary, Tel.76 74273John.Eades@cern.chISTC    Secretariat:  Monique Budel (Bldg. 14/4-022)  Tel.76 74270Monique.Budel@cern.ch

Minutes of the first meeting on Monday 27th September 1999

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