Minutes
from REX meeting 2005-06-01
Present: Mats Lindroos (chair), Fredrik Wenander, Luis Fraile, Nikolai Trofimov,
REXTRAP and REXEBIS
* A
venting incident of the REXTRAP happened this weekend when a surplus of gas was
let in via the leak valve. This affected the vacuum in the trap ion source, the
trap, the BTS and the mass separator. As the Simatics
system for the vacuum is still not fully automatic, the pumping down had to be
carried out manually.
* A
mass scan of the target for SeCO has been done at the
ISOLDE off-line. Significant amounts of stable Se from the mass marker and Mo
are seen in interesting regions, and this can cause saturation problems and
identification problem inside the trap.
* R.
Savreux and I. Podadera are
continuing with the emittance measurements. During evenings and nights the beam
is left to WITCH.
*
The electrical noise on the last drift tube inside the EBIS was found to come
from mechanical vibrations. Even with the motor-generator switched off they are
present, so if careful injection optimization has to be done the air
ventilation (major source for vibrations) has to be switched off.
LINAC
* 30 Hz period
time, as used last year for the Se, is not feasible this year due to power
restrictions in the 100 and 200 MHz amplifiers even with only 500 us RF
on-time. A longer breeding time with 20 Hz repetition rate was decided on. A
higher charge state could be reached and the desired energy of >2.8 MeV/u more easily reached by the amplifiers.
* Thomas has
improved the beam spot on the Miniball target and
achieved a transmission of 80%, to be compared to 85-90% last year. The
possible reasons for the lower transmission were discussed.
* Also the second
mobile Colutron MCP broke when it was vented. It
seems to be an inherent design fault. Thomas will modify them and use our own MCPs.
* The broken
transformers for the two 100 MHz amplifiers should soon be sent back to
Controls system etc
*
The BD FEC still keeps on stopping and has to be rebooted. More seriously, a
re-registration of missing dll-files had to be
carried out again in the beginning of this week. S. Catin
is following the problem.
*
Nikolai reported on a series of meetings within the CO/PO/BD/OP groups
concerning the plan of action and time schedule for the new CS for REX. No real
conclusions reached. The writing of the application programmes
is neither fully sorted out.
*
Even if the change to the CS for the beam optics will not take place in June
some hardware tests will anyway we carried out by N. Trofimov
et al. and then the system will be reverted.
*
Thomas will discuss with Jose Marques concerning the implementation of the RF
controls in the new CS to check what the RF group requests’ concerning extra
diagnostics are.
*
Fredrik agreed on writing an answer to B. Frammery’s
proposed plan of action for the implementation of the new control system.
Minutes
taken by Fredrik Wenander