Minutes from REX meeting 2005-03-24

Present: Pierre Delahaye, Mats Lindroos (chair), Ivan Podadera, Fredrik Wenander, Romain Savreux, Nikolai Trofimov, Thomas Sieber, Nicolas David, Andreas Ekstrom, Manuela Turrion

General issues

* S. Myers has agreed to work for an increase of the ISOLDE experimental area budget from 20 kCHF to 250 kCHF for 2006. This will include technical support for shutdown work (technician hours bought on industrial support contracts), installations and general technical improvements of the ISOLDE and REX experimental area. E. Siesling and M. Eriksson will work half time as technical support for the ISOLDE hall. One full time post (50% REX operation and 50% technical support for the low energy part) has been asked for 2006. During an interim period J. Lettry’s section has agreed on giving technical support to REX.

* M. Turrion presented the new ISOLDE database for target yields, produced within the TARGISOL framework (see presentation). The idea is to also incorporate REX-ISOLDE beams and yields. Pierre and Fredrik agreed to complete the parameters to be included in the database.

* In a presentation by N. Trofimov the progress of the migration of the REX control system was presented (see presentation). It is progressing well. The manpower for the application programming is still to be resolved, but Nikolai agreed on being a supervisor for the person. Thomas and Fredrik should also test the response time of the new control system to see if it is acceptable.

* There is still some important work remaining to be carried out by the different support groups before REX can be started up. We would like this to be finished within the next 2 weeks.

REXTRAP and REXEBIS

* The REXTRAP emittance measurements have been stopped due to a broken power supply in the emittance meter. This is under repair and the measurements will resume asap.

* The controller for the borrowed (ISOLTRAP) turbo pump to the emittance meter is also broken and has been sent to Mainz for repair.

* The implementation of the new REXTRAP control system is continuing.

* A summer student from Heidelberg will arrive this summer. He should work on the mass resolving power of the trap, carrying out simulations and tests.

* The DDS module (the RF amplifier module for the magnetron/cyclotron excitation) is broken again. Michael O’neil has been asked to repair it and Nicolas David to implement preventions so it doesn’t break that easily in the future.

* The modification of the turbo pumps in the BTS to allow for the present installation angles is more difficult than expected. 90 and 45 deg angle pieces are necessary. This is a major and expensive job not budgeted for this year. The vacuum group will be asked to deal with the problem for next shut down.

* Andreas Ekström, a student of Joakim Cederkäll has arrived, and will stay for 3 months. He will mainly work on beam simulations and mechanical design of a bender-kicker after the REX mass separator to divert the beam to the mobile tape station.

* The controller one of the turbo pumps in the mass separator keeps on stopping. A solution has to be found by the vacuum group before the run starts as it will inevitable stop the beam during the coming runs.

* The special insulator in the deflector-lens package inside the EBIS that was found broken has been replaced by a temporary solution.

* The high return pressure for the demineralised was investigated. Instead of 1.5-1.7 bar the pressure is 3.1 bar. The high return pressure results in a too low flow inside the bore cooling mantle and ice build-up, with a tube deformation as a result. No single item in the hall is responsible for the high pressure but each element in the Linac contributes with 0.1 to 0.2 bar. Thomas will try to reduce the flow to the different parts. E. Siesling will launch the installation of a drain pump to be put after the EBIS water outlet to reduce the return pressure. This is however a lengthy (>2 months) procedure and an intermediate solution has to be found if the EBIS should be started before.

LINAC

* Thomas visited Munich last week to coordinate work tasks with Berdermann (Bertronix) Berdermann will arrive to CERN after Easter to repair the 200 MHz amplifier. A new design for the anode capacitor is made and pieces manufactured. Berdermann has also reprogrammed the Simatics to suppress certain interlock signals for a few seconds. This should decrease the number of unnecessary switch offs.

* Thomas also met Hegewisch (responsible for the electronics workshop at LMU). Hegewisch will modify the low power RF modules. They will be send from CERN the 8/4 and thereafter he needs two weeks for the repair. For the delay units a relay will be exchanged.

* The pulse unit is also under modification so the Linac can operate with 50 and 100 Hz.

Next meeting will take place 16:00 the 7/4-2005, in ISOLDE visitor’s room, build 26-1-022.

Minutes taken by Fredrik Wenander