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

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CERN/INTC 2000-035INTC 59 October 2000ISOLDE AND NEUTRON TIME-OF-FLIGHTEXPERIMENTS COMMITTEE (INTC)Minutes of the Fifth Meeting onMonday 25 September, 2000OPEN SESSIONThe Chairman opened the meeting with a few brief words of welcome, after whichM. Lindroos / PS, discussed the present technical status of the ISOLDE facility. He reported thatthe HRS front-end was successfully installed in week 20, achieving a resolutionM/D M = 4200 ± 400 and that the first experiment was done with it in week 22. However,mechanical problems with the extraction electode subsequently caused the cancellation of the next(UC target) run. A recent contamination incident has resulted in a revision of the radiation safetystatus of ISOLDE. A two-year plan will require the target area being treated as a 'class A' areaand the experimental area as a 'class C' area. Furthermore a spare front-end is expected withinthe next year and a new generation of front-ends within a three-year consolidation period.M. Lindroos also described briefly the status of the neutron converter and other targets.T. Nilsson then presented a status report on the ISOLDE scientific programme. So far185 experimental and 25 test shifts of radioactive ion beams have been delivered. The GeneralPurpose Separator and PS Booster have been stable and the target performance good. On theother hand, in addition to the HRS problem mentioned above, a CeO target run has had to becancelled owing to technical problems with the robot. A further 120 RIB beam shifts arenevertheless expected on the GPS before the end of 2000, and 50 additional HRS shifts are alsoscheduled. A test of 600 MeV PS Booster operation is being discussed which may benefitseveral experiments through increased yields for some isotopes.E. Radermacher then presented a Status Report for the nTOF facility. The nTOF was readyto run on August 2, but reliability questions about the target water cooling systems and targetremote handling were raised by TIS. The requisite modifications are under way and the firstbeam is now expected at the end of October.P. Pavlopoulos, presenting the scientific status of the nTOF, pointed out that in measuringneutron cross-sections its general aims are threefold: 1) a better understanding of StellarNucleosynthesis, 2) applications in nuclear technology and Dosimetry, and 3) studies of nuclearphysics and neutron properties. He outlined the status of both the already submitted proposals,and those expected up to the September 2001 session of the INTC. An integrated intensity of2x1019 protons on target per year is the eventual aim. He indicated in addition that a TDRproviding a detailed description of the experimental hall and equipment, as well as a plan for theconstruction of these, will be submitted to the INTC for its next session. Concerning questionsabout the responsibilities for individual experiments, C. Détraz pointed out that the nTOF isintended to become a general facility, and that spokesmen will eventually be designated for eachexperiment carried out on it.D. Habs then presented a report on the status and perspectives of the REX-ISOLDEfacility, first describing the situation concerning various components of the accelerator and thenthe tests of the Ge miniball detectors, PPAC etc. that have been taking place in Cologne. A firsttest experiment at ISOLDE is now expected between 20 November and 25 November this year.This will be devoted to measuring charge breeding yields for ions and molecules and to lightmass RIB intensities, but will also include beam, target and detector tests.2A presentation was then made of the proposal:P130 (INTC 2000-029): Measurement of Moments and Radii of Light Nuclei by CollinearFast-Beam Laser Spectroscopy and ß-NMR Spectroscopy.CLOSED SESSION    Present  :  B.W. Allardyce, J. Aystö, C. Détraz, J. Eades (Secretary), H. Flocard (Chairman),K-L. Kratz, M. Lindroos, T. Nilsson, J-P. Riunaud, B. Rubio, W. Scobel, R. Voss,P. Walker, K. P. Lieb, K. Langanke, E. Migneco.Apologies   : H. Ravn, P. van Isacker, C. Rossi-Alvarez, J-P. Duraud.The minutes of the fourth meeting were first approved with the exception of thetypographical error that made 1:6000 appear as 16000 in discussions concerning the HRSresolution.The Committee first discussed the various technical and scientific progress reports asfollows:1.    nTOF Technical Report  The Committee took note of the situation reported by E. Radermacher in his open meetingpresentation and hopes that in spite of the delay related to CERN TIS division's reliabilityconcerns, full commissioning and calibration of the nTOF facility will be possible thisyear.2.    External Referee's Report on nTOF TDR    Following the last meeting, the external referee, G. Bauer, had prepared a list of questionsconcerning this report. His conclusion was that the collaboration had been verycooperative in answering these, and that the nTOF would certainly work at the intensityrequired for proposed and forthcoming experiments during the next year at least.Nevertheless he felt that there was still a need for a single coherent document giving acomplete description of the facility, rather than the collection of reports and paperspresented in support of the TDR (CERN/INTC/2000-004, 11 February 2000). TheCommittee therefore accepts the TDR with the proviso that such an overall document bepresented during the course of the next year. C. Détraz also pointed out that this approvalrepresents a milestone for the nTOF, since it is now well on the way to becoming a generalfacility. This means that the responsibility for operations up to a suitable point before thedetector area will shortly fall on CERN. The INTC will from that time onward concentrateon questions concerning the experimental proposals.3.     Referee's Review of nTOF Proposals   This concerned mainly the experimental proposal P123 (Determination of the neutronfluence, the beam characteristics and the backgrounds at the CERN-PS TOF Facility)presented in the February meeting regarding the commissioning of the nTOF. TheCommittee had then requested further details on the planning and implementation of thesestudies. W. Scobel has had extensive contacts with the nTOF group. The delay of thenTOF commissioning previously scheduled for June/July has provoked some rethinkingand a full TDR on the experimental hall and the experimental apparatus is now eagerlyawaited by the INTC. In the meantime, W. Scobel will raise with the nTOF group thequestions outlined in his review. It is clear that closely related questions concerningproposal P124 (The importance of 22Ne( a, n)25M g as s-process neutron source and thes-process thermometer  151Sm., discussed in the May meeting) may usefully be addressedat the same time.34.   ISOLDE Technical Report  The Committee took note of the points raised in M. Lindroos' report, especiallyconcerning the need for a spare front-end immediately and for a new generation of front-ends over a three year timescale.5.   ISOLDE Scientific Report  The Committee noted with satisfaction that the number of shifts delivered to theexperiments this year is already equal to the number delivered during the whole of lastyear, and that 50 additional HRS shifts are planned. The Committee also strongly supportsthe proposed tests with 600 MeV Booster energy, although it understood that 600 MeVoperation, if successful, can only be done when the Booster is reserved for ISOLDEalone.6.     REX ISOLDE Report on Status and Perspectives   The Committee took note of the progress made on REX-ISOLDE and looks forward toseeing results of the expected November and winter tests by the February meeting.The presentation of proposal P130 (Measurement of Moments and Radii of Light Nucleiby Collinear Fast-Beam Laser Spectroscopy and ß-NMR Spectroscopy) was thendiscussed. The Committee agreed on the importance of the Ne and Li studies. It thereforewill recommend to the Research Board that the 30 RIB and 15 stable beam shifts beallocated for these studies. However, the case for the Ar studies was not thought to havebeen demonstrated in a convincing manner yet, and will not therefore be supported.Following the Committee's earlier criticism of P85 Add 1 (Investigations of deep-level Fe-centres in silicon by Mössbauer spectroscopy) the authors have submitted a revised addendum(Investigations of deep-level Fe-centres in silicon by Mössbauer spectroscopy;INTC 2000-031/P85 Add 2). This has convinced the Committee that the proposed studies willclarify an important process that may be used in semiconductor technology, and will recommendthe 10-shift allocation of beam time to the Research Board.OTHER BUSINESSP87 Add 1 (Letter M. Hass, Spokesman IS303 - proposals 91-11/P8 and 96-31/P87):This was one of the backlogged experiments (IS303) discussed in a previous  meeting ofthe INTC. As the group now expects to bring to CERN the superconducting cryostat that wascausing the delay, and to provide the manpower to test it during the winter, it was felt that theoutstanding shifts can be reallocated, provided that the experiment is finished next year aspromised.The next INTC meeting is on Monday, November 27 , for which the deadline forsubmission of proposals will be Friday, November 3, 2000.The dates of the INTC meetings for 2001 are:February,  26-27April 23-24September 24-25November,  26-27.John EadesScientific Secretary; tel. 76 74273John.Eades@cern.chINTC Secretariat:  Monique Budel (Bldg. 14/4-022); Tel. 76 74270Monique.Budel@cern.ch

Minutes of the fifth meeting on Monday 25 September 2000

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