Minutes from REX meeting 2005-07-27

Present: Mats Lindroos (chair), Pierre Delahaye, Thomas Sieber, Ivan Podadera, Luis Fraile, Georgi Georgiev

General

* A summary of the Cu run can be found in the attached document.

* The concern about who is taking over Romain’s responsibilities and control system knowledge in case he leaves in the end of September was raised. We hope to be able to keep him until the end of the run and possible find a CERN PhD position for him. Fredrik was asked to lobby within the AB division. A full documentation of the new Labview based control system for the REXTRAP should be compiled by Romain.

* The need for alignment support was once again underlined. For the extension of the Linac new coordinates are required and for the present EBIS alignment fixed points are missing since the removal of the wall to the hall extension. E. Siesling is in contact with the Metrology group and Mats will send an email to the group leaders involved.

* The new ISOLDE schedule is on the web. Some rearrangement in time and beams for the REX runs have been done.

* Thomas was asked to arrange a contract for Didier Voulot (the person taking over after Thomas) with Dieter Habs. Didier will arrive the 1^st of August and stays in Thomas group and office. Thomas leaves around the 20^th of August. The folders and documentation stays in his office.

* A diploma student should start the 1s of October to work on the beam transport for HIE ISOLDE. A beam optics specialist supervision is searched for.

TRAP and EBIS

* Nicolas David has started to look into a spare DDS unit for the RF generation for the trap.

* An upgrade of the REX Windows 2000 machines has been done by Romain.

* A new simplified and improved version of the trap control system was launched at the same time as new versions of Labview and Twincat were installed.

* Continuous instead of pulsed injection was tried into the EBIS with a promising result of 2% in one charge state (K10+). This is a significant improvement compared to previously published results at other machines. Romain hopes to also have the new scanning interface ready for a test in mid August.

* A preliminary list for jobs still remaining, and coming up for the shutdown, for the low energy part was presented. The groups involved are to be informed by latest September.

* The Profibus slave at the EBIS gun platform has stopped twice (once during the Cu run) causing the electron beam to shut down. Nicolas David is informed about the problem.

* Ivan has summarized the rotative wall measurements (emittance and injection into the EBIS) in a preliminary report. A discussion of the content and results should be hold amongst the involved.

LINAC

* The Linac was running stable during the last run with <60 kW on the 200 MHz amplifier. It is hoped that with similar operation conditions it can last until the end of the running period (October).

* An RF specialist, Werner Pirkl, had a look at the 200 MHz system and found nothing exceptional from the pickup signal. However, it was found that the capacitor, part of the amplifier cavity, could had a resonance at the operation frequency This could be the cause for the heating of the ferrite blocks. The idea is now to cut the middle plate of the capacitor into three pieces to disable the resonance mode, and then operation at 100 Hz might be feasible. The modification will be tested after the Sn run.

* There is a problem with sticking piston tuners. The malfunctioning tuner at the IH structure was exchanged for the second one installed but not in use. The 9-gap cavity was opened and the uner inspected but no obvious fault was detected.

* Oliver Kester has found two dipoles and quadrupoles at GSI that could be used for the move of the Miniball to the new hall.

* Thomas has asked Heidelberg and Munich for Linac drawings to be included in the ISOLDE drawing library, presently being updated by an external consultant. The compatibility of ProE 3D with CERN drawing programmes has to be investigated.

Minutes taken by Fredrik Wenander