Minutes from REX meeting 2005-02-24

 

Present: Mats Lindroos (chair), Richard Scrivens, Pierre Delahaye, Luis Fraile, Georgi Georgiev, Romain Savreux, Nicolas David, Nikolai Trofimov

 

 

General issues

 

  • The HIE-ISOLDE project is on its way. Mats sent an excel file by mail to the REX team concerning the required founding for the related tasks at REX-ISOLDE. The REX support team is asked to give comments before the 2nd of March. This concerns the upgrades to 5.4 and 10 MeV/u, but also the projects at the low energy stage such as the new EBIS cathode.
  • In next September the INTC will make the review of REX-ISOLDE. This meeting shall be determining for the HIE project at REX.
  • The NUPAC meeting (NUclear Physics and Astrophysics at CERN ) will be organized by the INTC on request of the CERN management this year. It will be a good opportunity to present the last two years of operation of REX-ISOLDE and all the related developments
  • Luis asked for a detailed list of requirements from REX this year for MD. This concerns mainly the offline beam requests. Thomas and Pierre shall meet this week together with Luis to define this program.
  • The WITCH team asked for a schedule for the tests at REX in order to define their possibilities for optimizing their setup. In the future Pierre shall help them since he’s involved in their experiment through the TRAPSPEC JRA.
  • Nathal Severijns, team leader of the WITCH experiment, reported that they are studying several solutions to avoid the magnetic field distortion at the separator during the WITCH operation.
  • Georgi pointed out that photomultipliers don’t work properly with an environment of 15 Gauss. The detector installed at the separator shall be also protected by m-metal for a correct operation.

 

 

REXTRAP and REXEBIS

 

* The Munich emittance meter has been installed. It is ready for emittance measurements but should be returned in the end of February / beginning of March. More time for these has been asked to Oliver Kester.

 

* Last week Sophie Meunier together with a Pfeiffer technician took in charge the greasing / oil change of the REXTRAP, ion source and BTS turbo / roughing pumps. It seems that the Pfeiffer turbo pumps installed in the BTS line are not correctly oriented for a correct operation. At more than 90° from the bottom position the oil of the bearing is leaking and lost into the vacuum tubes. A modification is possible to circumvent this problem. Sophie has been asked by Richard to contact Pfeiffer for an offer. This intervention should take two days and could be done around mid March.

 

* The commissioning of the new CS at the trap goes very well on tracks. A time of flight signal could be obtained. 30% trapping efficiency could be reached with non-optimized settings.

 

* The voltages of the trap electrodes are not always according to their monitor values.  Nicolas will have a look at them for a recalibration

 

* A shortcut of one of the excitation electrode at the trap has been found. The trap magnet had to be open and taken apart from the beam line. The problem was very quickly fixed by Romain, Ivan and Pierre. 1 day only was necessary to open the trap, fix the problem, and pump back.  Most probably the guilty connector was inside the injection cross-tube which made things easier. Once this cross tube was dismounted the shortcut disappeared.

 

* The power regulation of Michael O’Neil works very nicely. Mike is in principle curious to know about the ion source stability with such regulation. Later on a similar regulation should be installed at the EBIS for controlling the cathode heater.

 

* Mike had a solution for the trap ion source sparking problems at 60kV. This would be simply to install some metal tube around the connection of the ion source through the high voltage cage of REXTRAP.

 

* The alignment of the EBIS magnet was finished at the end of last week by Fredrik and Richard. An alignment of .15mm in every dimension could be reached. The probe has been returned.

 

* A rather long standing problem concerning the EBIS and LINAC cooling systems was reported by Richard.  The water pressure coming from the water station is too high. It hinders the normal operation of the cooling devices in the ISOLDE hall.

 

LINAC

 

* Nicolas is working on the beam optic supplies of the LINAC.

 

CONTROL SYSTEM

 

* Sylvestre Catin will learn about the windows-based PC from Ivan Deloose in one or two weeks. Because of Ivan’s change of position it was tricky so far for him to give a full introduction to Sylvestre.

* The development of beam line control system by Nicolaï goes very well. He reported that all the control for power supplies are already running. In the future the OP group will help Nicolaï for the development of the application software.

 

 

 

Minutes taken by Pierre Delahaye