Minutes
from REX integration meeting
Present: Mats Lindroos (chair), Luis Fraile,
Pierre Delahaye, Fredrik Wenander,
Ivan Podadera
1. Planning and general issues
* At the next REX
meeting Wednesday 12/5,
* The IS399 Li-run
has been postponed and will not take place in end of May. Instead a solid state
implantation run, using only the RFQ as accelerating element, is scheduled.
Praseodymium A=143 is requested as radioactive beam, together with stable
Europium (or Cesium as mass marker for beam setting up). A surface ionizer at
GPS will be used. Target to be put on the frontend
Monday 23/5.
* Two new computers
form
* The REX workpackage has been updated by
Fredrik and sent to Mats Lindroos, Charles Hill and
Richard Scrivens.
2. REXTRAP
* The emittance
measurements are still continuing. Efficiencies and emittances for rotating and
sideband cooling are studied as function of cooling time, electrode voltage and
beam intensity.
* The HV for the
REXTRAP caused some sparking last week. The sparks are believed to occur
outside the vacuum, and all insulators and the transformer were therefore
cleaned again. The reason is unclear, but the sparks are gone for the moment.
* The DDS module
(function generator for the trapping elements) was broken and repaired again.
* The spare ion
source has been assembled and a Rhenium liner has been inserted into the
graphite oven to enable ionization of Li. The tungsten wires will be exchanged
for Re wires. A mass marker with 1000 nA
hours Li (10% ionization efficiency included) will be prepared by ISOLDE
technical group.
* A brief discussion
with Jacques Lettry concerning further developments
of the REXTRAP ion source was held. The following conclusion
were reached:
1.the Li
production should be tried with above described method
2 separate mass
marker ovens should be installed
3. possibly
use a plasma source (with no gas feeding and small plasma electrode hole)
4. possibly
use a source similar to the future ISOLTRAP source which has a built in RF spectrometer
for mass separation
* A 500 um Si detector mounted behind an Al-foil has been produced.
The detector assembly is mounted on a CF100 flange and will be put after the
trap when the emittance measurements are finished. This may improve the radioactive
beam identification after the REXTRAP.
3. REXEBIS and mass separator
* A set of spare
parts for the REXEBIS HT 60 kV FuG supply has been
ordered for approximately 300 euro.
* The LqHe boil-off rate is still too high. When trying filling
Tuesday evening the dewar
was almost empty, so the solenoid had to be demagnetized. The solenoid has been
refilled on Thursday and ebeam is running again. The
Helpdesk at Oxford Instruments has been contacted, but no response received
yet.
* Beam injection
tests are scheduled for Monday-Tuesday.
* The MCPs in the mass separator were rewired to improve the
vacuum and to correct for faulty connections. Four not vacuum tight SHV
contacts have been changed for Fisher Lemo
connectors.
* The mass separator
has been pumped on. The Alcatel vacuum controller for a turbo pumped stopped
working. This reoccurring problem will be addressed by David Porret.
* One of the EBIS steerer
supplies is under reparation by Nicolas David.
Notes by Fredrik Wenander