1) Due to the low magnetic field in the booster (according to the CDR from 0.005 T at 20 GeV to a maximum peak of 0.046 T at 182.5 GeV, with a rate of field change below 0.03 T/s), the eddy currents are not a problem
2) The geometry of the vacuum chamber could be the simplest one: circular (to avoid, for example, quadrupolar effects) with a radius of about 30 mm
3) Since the eddy currents are not an issue, we can think of stainless steel with a copper coating of 1 mm, so that, from about 2 KHz on, the skin depth is such that the beam sees only the copper
4) One simple way for the realization of the vacuum chamber could be to introduce a stainless steel strip of about 1 mm (more?). This will produce an azimuthal asymmetry in the impedance. This strip has to be studied in detail from the impedance point of view: what is the difference with respect to having all copper (in particular in the transverse plane)?
5) Every about 8 m, where there are the vacuum flanges, there could be some small insertions (of a couple of mm) that need to be evaluated from the impedance point of view.
6) Ali is developing a code to evaluate the RW impedance for any geometry and in the multilayer case. He will simulate the Booster RW impedance and the effect of the stainless steel strip
7) Together with Reinor and Ali, once we have a first evaluation of this RW impedance (and wake), we will start to run PyHEADTAIL to see the microwave and the TMCI instabilities.
