Minutes from REX meeting 2005-10-07

 

Present: Mats Lindroos (chair), Didier Voulot, Pierre Delahaye, Romain Savreux, Nicolas David, Han Broere, Henrik Bak Jeppesen and Fredrik Wenander

 

 

General

 

* It was agreed that Romain Savreux’s contract is prolonged for one month, now until the end of November. That would leave him time to include yet a few features into the new REXTRAP control system. Romain will contact LPC for a temporary contract.

 

* Sylvestre Catin should come the next week to help Romain with memory upgrade and to learn about the new REXTRAP control system so he can take over the responsibility when Romain leaves.

 

* Mats will remind the Operation group of the need for two programmers from the 1st of Nov for the REX application programmes.

 

* Fredrik has started collecting work tasks for the REX shutdown work list. The list will be sent to the concerned groups within the next couple of weeks for them to fill in missing items.

 

* The Zn run had to be cancelled due to a failure in the Linac, see below.

 

 

 

TRAP and EBIS

 

* Romain continues with the documentation of the REXTRAP CS and to implement the last features.

 

* The efficiencies for the trap and the EBIS were exceptionally high when the system was setup for Zn.

 

Trap:    55%  69Ga (11-12 pA trap inj plate, only Ga in the TOF, 9.8 Hz and beam gate open)

EBIS:   10.4% for 18 ms breeding time, charge 15+

19% for 69Ga21+ at 98 ms

 

Trap:     55% 115In (30 pA on trap inj plate, beam gate open)

EBIS:    9.7% for 115In27+ (charge peak)

 

Trap:    50-60%  68Zn (10-11 pA on the inj plate)

EBIS:   12% for 68Zn21+ at 98 ms (trap cyclotron frequency not optimised)

 

 

 

LINAC

 

* The IH structure failed on Tuesday. The Grid 1 power supply burned and the predriver amplifier failed. A spare amplifier is available at CERN, but it needs modifications. In case the spare items ordered from Berdermann will not arrive, this can be used.

 

* The 200 MHz amplifier still trips. The previous problems with the parasitic resonance mode and the heating of the amplifier cavity are solved, however new problems have surfaced. There remain for example air flow problems and HV breakdown in the tube between the anode and grid 2.

 

* In a first stage the amplifier will not be sent back to CERN, but Berdermann will come here in November to look into the problem

 

* Due to lack of parts for repairing the amplifier and missing manpower (two persons ill in the RF section, lot of time invested already on the 200 MHz and LEAR requesting an urgent intervention), the Zn run had to be cancelled.

 

* Didier will arrange more stripper foils for the next run as the installed foils most likely were broken when the experimental station was vented.

 

* D. Habs will apply for a BMBF grant for the 5.5 MeV/u Linac upgrade.

 

 

Minutes taken by Fredrik Wenander