Minutes from REX meeting 2006-04-26

 

Present: Mats Lindroos (chair), Didier Voulot, Fredrik Wenander, Pierre Delahaye, Han Broere, Sven Sturm, Karsten Riisager, Luis Fraile and Nikolai Trofimov

 

 

REX low energy part

 

* REXTRAP delivered successfully stable potassium beams for WITCH.

 

* Pierre and Sven are preparing REXTRAP for experiment IS437 using CaF to avoid contamination with 38K.

 

* A second cathode failed in the new EBIS gun as well. This is a concern for the coming runs. A third spare cathode is available and some more have been ordered. The problem is not well understood yet. The old gun will be reinstalled when the new cathodes arrive.

 

* The ISOLDE scheduled machine development run and Linac emittance measurements in May will have to be cancelled.

 

* A new bore cooling tube have been ordered from Stockholm (2 weeks delivery time vs 6 weeks at CERN).

 

 

REX linac

 

* A major vacuum leak occurred on the 9-gap cavity following tests with RF power. The leak was found on the metal seal between the middle frame and the lower shell. This could be completely fixed by tightening the bolts some of which were relatively loose. Spare seals will be ordered and ready to install. Tests will be carried out with RF power.

 

* The Bruker power supply was moved to allow for better shielding of Miniball from the cavities. Concrete blocks will be added to the existing lead screen.

 

 

Move into the extension

 

* Minimove phase I (shifting the experiments into the hall extension without modification of the beamlines after the switching magnet) has been accepted by EATC. The start date for the project is 15th of May.

 

* The full installation will come latter as part of HIE Isolde.

 

* A short presentation of Minimove Phase I will be given by D. Voulot in the next meeting.

 

 

New control system

 

* The response time of the different elements has been tested. The time for the power supplies to establish a new value is generally good (real time feel). The time for the read back value to come up is quite poor (up to 2s) however this is not a concern for operation.

 

* A fault has been detected on the separator magnet power supply causing slow stabilization. Nicolas David is looking into the problem.

 

* The main concern for response times is for the mass scanner application. This application is in principle ready. Tests should be carried out shortly.

 

 

Next meeting in two weeks.

 

 

 

 

Minutes taken by Didier Voulot