Minutes from REX meeting 2006-08-30
Present: Mats Lindroos
(chair), Didier Voulot, Christian Dutriat and Matteo Pasini
Li run
* REX is set up for 8Li run. Efficiencies are OK for the low energy part
(~20% trap, 13% EBIS) and for the linac (75-85%). Some radioactive beam was
delivered overnight but the yield is very low (100 times lower than expected).
* Stripper foils are used to get rid of the 16O contamination. An extra
very thin (4ug/cm^2) C foil has been installed between the RFQ and buncher. It is
expected that this extra foil will increase the Li/O ratio: charge distribution
and energy loss should favour Li over O.
First tests on Monday night showed an increase of 8x in Li/O ratio with
this extra foil (for a 6x decrease in absolute Li intensity). Unfortunately
beam intensity is too low to operate with this double stripping arrangement. So
only the standard 25ug/cm^2 stripper foil at the linac output can be used for
data taking.
* The linac RF is performing exceptionally well: 3.15MeV/u at 50Hz/900us
with very few interruptions. Also the instabilities expected at these low
levels (A/q=2.666 -> RF power below 30kW in the IHS) have not been seen.
Installation
* Mechanical
design is now finished and construction of the different supports and beampipes
is now starting.
* An
updated budget for Minimove phase1 is attached to the minutes. The final budget
will be over the planned 156kCHF and more likely around 200kCHF. This is mainly
due to: extra pumping group, cost of mechanical design/construction and cable
trays. Most of the cabling is already included in the power supplies cost.
* An
updated schedule will be prepared. So far, installation of alignment points and
painting of floor lines are planned for next week and following (week 36-37),
installation of cable trays, power, cooling water and compressed air pipes are
planned for the second half of September (week 38-39). The refurbished magnets
and their support frame will be ready before end of October (week 43).
* New
diagnostic boxes of the REX type will be produced by
General
* REX
weekly meetings will be held from now on together with Isolde technical
meetings on Tuesdays at 11:00.
Minutes taken by Didier Voulot