WW reported that the BT budget allocation for
LINAC4 related work in 2008 is presently 450kCHF out of the 690kCHF
requested. TF mentioned that the activities on the distributor pulse
generator for BI.DIS, injection bumpers BI.BS and painting bumpers BI.KSW
are moved to 2009 and that APT has been updated accordingly.
WW mentioned that following the L4/PSB commissioning WG of 10
April the aperture limitations of transfer line and PSB injection
the BI.DIS aperture can be accepted. Furthermore, the L4/PSB commissioning WG
plans to look into the optics of the last part of the transfer line in order
to reduce the beam size at delicate locations (beam waist somewhere around
the entrance into the SMV - as probably at present). The
PSB Injection Geometry for the
SMV magnets shows that the ~3.5-3.8 mrad baseline kick strength
of the BI.DIS magnets, in combination with a ± 16mm beam size as
communicated by Mohammad Eshraqi, will not give sufficient clearance at the
BI.SMV magnets. A minimum ~4-4.5 mrad kick strength will be required
in order to avoid beam losses on the BI.SMV septa. These changes will also
require a performance increase of 2.2 in ∫B•dl for the BI.DVT30, BI.QNO30,
BI.QNO40 and BI.DVT40 instead of the baseline 1.9 increase. TF communicated
that a maximum 5 mrad kick strength can be produced within the baseline
pulse generator specifications. This will require a corresponding increase
in PFN voltage from approximately 23.75kV to 26.75kV which is feasible
without major upgrade, however less margin will be available on the power
supplies as the re-use of the Technix 30kV capacitor charging power supplies
used BI.DIS electronics consolidation is foreseen. JB added that this seems
all compatible with the target voltages for the magnet of 30 kV.
3rd point ("The BI.BS fall time ...."):
I understood that we agree on D=0m at the injection point as baseline, but
aim for keeping apertures compatible with a matched dispersion. Furthermore,
the total number of foil hits is increased significantly going from D=0m to
a matched dispersion. The hit density and it's dependance on the BI.BS fall
time is altered only a bit.
The
BI.BS fall
time requirements in relation to matched and mismatched
dispersion Dx, as presented by BG during the
previous meeting, were discussed. It was
decided that zero dispersion Dx at the injection point shall be
used as baseline design, but aiming to keep apertures compatible with a
matched dispersion. It was noted that the total number of foil hits is
increased significantly going from D=0m to a matched dispersion. The hit
density and it's dependance on the BI.BS fall time is altered only a bit
thus relaxation
of the BS fall times will be possible.
JB presented 1st order quantification of
eddy current effects in
pulsed laminated magnets with 0.35mm lamination thickness
indicating a 26μs eddy current time constant in the yoke. This can be
accepted in case it will be identical for all magnets. The choice of a
relatively thick lamination (~0.35mm) will thus be acceptable, having a
positive influence on the vacuum load as well as on the filling factor of
the magnet.
MH gave a status report of the BI.DIS, indicating that the special purpose tooling for coil welding by laser is being studied. A prototype coil is expected to be completed by the end of the summer and tested by the end of the year.