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LHC. L=10 27 cm -2 s -1 with b =0.5m and ~600 bunches MAX limit due to quench (safety margin negative) and central detector limit (8 barn over ~437 are useful) . Leads to 7 10 7 ions/bunch.
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LHC • L=1027 cm-2s-1 with b=0.5m and ~600 bunches • MAX limit due to quench(safety margin negative) and central detector limit (8 barn over ~437 are useful) . Leads to 7 107 ions/bunch. • Min limit due to resolution of BPM’s (2mm at 1.5 109 charges/bunch) i.e. 1.8 107 ions/bunch at the end of coast …4 107 at the beginning of coast!!! • Means at the exit of LEIR (eff.=30%) a minimum of 5.3 108 ions for 4 bunches in LHC…The maximum of 9 108 can be overpass if b>0.5m at the beg. of the coast but…
SPS • At SPS, injection limit due to incoherent tune shift(0.07) and IBS growth rate overcome by: • Increase Br to 88 Tm (same as LHC proton, 2.4 s cycle) • 4 pairs of bunchlets created in PS(200MHz) recombined in SPS (100MHz system) • Kicker rise time ~200ns implies batch of 4 bunches separated by 100ns, new LHC filling scheme (592b/ring)…(could also be 50ns…PS investment ) • If there is no way to remove this tune shift limit then max from LEIR=9 108
LEAD SCHEME • 9 108 in LEIR 2 bunches (Lead 54+) • LEIR 4.8Tm to PS 2b. in h=1614 12… then split(4b.) to h=24 21 169 then split (4pairs of bunchlets) h=200. • PS 88Tm, stripping Lead82+ SPS stacking and accel.+ recombine pairs to 1b.(100MHz RF) then LHC. • Bunch pattern 3*(13+13+12)+1*(13+13+8)