[FFA_CEBAF_Collab] [EXTERNAL] Re: FFA at CEBAF WG mtg. this Friday, June 24 at 11:00 am

[Jay Benesch]

Colleagues,

One reason I've been pushing 4 EM at 1200 MeV and four FFA passes to ~20 
GeV is current capability.  At best the CMs can be pushed to ~720 uA 
total beam current.  Two halls at 45 uA each, eight passes totals 720 
uA.  If we're limited to 500 uA because a heat exchanger in the beam 
dump system is not upgraded and we can't lower cavity input Qs, 31.25 uA 
for each of two high current halls on last pass.  At 11 passes total, 
22.7 uA/hall at 500 uA total, 32.7 uA/hall at 720 uA total.  900 kW 
power limit per dump, so 45 uA at 20 GeV just works, while higher 
energies require less current.  A lot of the suggestions I've seen from 
the high current halls assume high luminosity aka beam current.

Jay