WW mentioned that under the Meetings on Linac4 a link to Conceptual Design has been added where the history and present status of the PSB BI line conceptual design can be found. The present status, revision 3, was discussed and the remark was made that the maximum beam sizes (slides 3-4) need to be checked with the L4 beam performance working group.
BG presented the
beta-beating effect of 0.37 m long magnets with 66 mrad deflection
angle. Configurations with an RBEND, SBEND, Combined function RBEND,
Combined function SBEND, and SBEND-0.5 angle shim were simulated resulting
all exactly in the same optical effect (apart from a change of gradient sign
between SBEND-CF and RBEND-CF).
JB completed the presentation with the results of a
feasibility study of a combined function BS(1) magnet, concluding that
the manufacture of a RBEND-CF would be preferred since the coils for both
magnets would be equally complex to manufacture but yoke construction of a
RBEND would be less complicated. 3D simulations of a RBEND magnet showed
that for a 400mm long magnet a magnetic length of 370mm can be achieved.
Furthermore did JB mention that the eddy currents in the vacuum chamber can
only be simulated once the required rise and fall times for the BS magnets
are known.
CC remarked that it will be useful to see the evolution of the dipole/quadrupole
ratio during the ramp. JB proposed to calculate for this reason the magnet
performance at different excitation steps. JB also suggested to test a
prototype magnet in order to validate the simulations.
Topic for future meeting:
- Realisation of the -10mm horizontal offset of the injected beam and DVT70
moved upstream.
- L4 Beam sizes at BT injection equipment (possibility to reduce BI.SMV
horizontal aperture)