Status of studies for the transfer line between Linac4 and the PS booster (South Hall project). Purpose: Transport the beam from Linac4 to the booster and meet PSB injection requirements so that beam can be captured in the ring with small losses.
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Status of studies for the transfer line between
Linac4 and the PS booster(South Hall project)
Transport the beam from Linac4 to the booster and meet PSB injection requirements so that beam can be captured in the ring with small losses.
Exact beam parameters (transverse and longitudinal) for matching into PSB still to be specified.
e rms long. = 0.174 deg MeV
Transverse matching as per 50 MeV injection ax =0. bx = 2m
ay=0 by= 4.22 m
=~200keV (keeping same RF in booster)
Technique: initial Trace3D design followed by multi-particle simulations (PATH, later cross-check with IMPACT) using beam distribution from Linac4 output.
G. Bellodi - Linac4 TDC meeting 04/04/06
Energy spread increase due to space charge saturates after ~18 m
Need to reduce energy spread of the bunch to <200 keV with one or more debuncher cavities.
D Phi < 50deg to avoid RF nonlinearities
2) Buncher cavities :
First one to be positioned at a distance of 20-30 m from Linac4 output (see plot)
Voltage required: V~ DW/cos(Df)~= 900 keV/cos(40o)=1.2 MV
Solution suggested by M.Vretenar is to use 4-cell cavities:
Max 0.3 MV per cell
1.2 MV total
Power limit 80kW
One cavity (@ full voltage) would probably just be sufficient for debunching, but second one (though at much lower voltage) would help to keep a larger margin to play with in meeting injection requirements on energy spread.
Studied at 65mA, in first approximation no strong sensitivity on beam current.
Keep bore diameter <40 mm Focus beam in the cavity
L = 7.2m