Minutes from REX meeting 2005-02-09

Present: Pierre Delahaye, Mats Lindroos (chair), Luis Fraile, Fredrik Wenander, Romain Savreux, Nikolai Trofimov

General issues

* The Miniball steering committee will decide when Miniball can be operational at ISOLDE, the tentative date is mid May.

* A technical stop of 1-2 weeks for REX-ISOLDE is planned in June/July for the implementation of the new control system for the Linac. The time needed is mainly dependent on the installation work required by the PO group.

* Luis requested input from the REX team concerning what development and tests that are needed for the beams to be scheduled this year. Some difficult beams were identified, such as: Se (molecular beam with high contamination), 138Xe (long breeding time), 11Li and 11Be (lifetime, cooling and injection efficiencies and contamination from the EBIS). If possible these should be tested in advance.

* The informal beam inquiry from Bo Cederwall in KTH, Stockholm, was shared amongst the REX team and we see no immediate problems for REX with the beams requested.

* Fredrik should contact Joakim Cederkall concerning his suggestion to support with mass resolution tests in the REXTRAP and take care of the commissioning of a beta detector and possibly installation of a tape state after the EBIS.

* Maria Jose Garcia Borge has been informed about the development plans for the 11Li beam. If possible the REXTRAP will try to increase the cooling efficiency using Ar as buffer gas. Thomas Sieber says that 100 Hz operation of the linac can be possible earliest in June, more realistic in July/August.

* The AB/CO group has arrange an industrial support contract for the REX PCs. The person in charge is Sylvester Catin. Mats has also agreed to pay Ivan Deloose 2-3 hours to introduce him to the ‘old’ control system.

* The manpower needed to write the application programmes for the new control system is not solved, and no easy solution is at hand. From the 1/10-2005 some support could come from the OP group, but Nikolai pointed out that the need is immediate. He also underlined the need for continued maintenance and support, over a longer time period than 2 years.

* One REX PC was brought to the PC shop with broken power supply.

* An updated version of the REX homepage is soon to be launched. Comments to its content and layout are still welcome to Fredrik.

REXTRAP and REXEBIS

* The Munich emittance meter is under installation after the REXTRAP. Hopefully the trap can startup on Friday.

* Romain Savreux is continuing working on the REXTRAP control system. The system will be tested during the emittance measurements foreseen for the next couple of weeks.

* A power regulation unit for the oven has been built by Michael O’neil. It should keep the emitted current from the local trap ion source constant. The evaluation will take place during the emittance measurements.

* The oil for the REXTRAP roughing pumps will be changed on Thursday. Also for the REXEBIS.

* A solution for the modification of the REXEBIS collector cross is found. The alignment should be finished this week.

* The cooling tube inside the EBIS bore was deformed. The reason could be ice building up due to insufficient water flow. The tube had to be cut up and removed and the baking band and insulation redone. A new cooling tube was rapidly produced and sent by MSL, Stockholm. It has now been reinstalled and the baking band is under installation.

* The B-field alignment of the EBIS has been time-consuming and difficult. The straightness reached previously can not be repeated, it is approximately a factor 2-3 times worse. If this affects the performance of the electron beam is difficult to answer. Richard Scrivens has spent a significant amount on time on this together with Fredrik.

* An inquiry to the different support groups about the progress of the shut-down work for the low-energy part of REX was launched. The AB/PO is ahead of schedule, while other groups still have to start their tasks.

* There will be no LHe delivery between the 23/2 and the 28/3. That means the EBIS has unfortunately to be warmed up during that time, and 4 days of cooling down time has to be added.

* A diploma student, Klaus Allinger from LMU Munich, will come to CERN in the spring to work on electron cathode and gun upgrades for the REXEBIS.

* Richard Scrivens will be asked to supervise the shutdown work while Fredrik is absent.

LINAC

* 100 Hz operation can be possible earliest in June. More realistic July/August (perhaps after the break we plan to have for LE lenses controls tests).

* The 200 MHz system is now in Munich for repair. Berdermann agreed that there are design problems with the rf-cavity (anode capacitor). He will modify the weak parts until mid February, reassembly and test at CERN is in the end of February.

* 4 spare MCPs are back from repair. They will be in the rf-cupboard.

* Nicolas David has installed the new Danfysik Power supplies for the Magnetic Lenses in the Target area. He will ask Sylvestre Catin for help for modification of database and control application.

Next meeting will take place 16:00 the 23/2-2005, in ISOLDE visitors room, build 26-1-022.

Minutes taken by Fredrik Wenander