2017 CAS Erice case study: Design of a beam dumping system for FCC Nuria Luca Georges-Henry Oliver Lorena Vincenzo

100 km FCC Layout 8.8 GJ stored in each beam. Requirements for a dumping system: Fast Reliable 1.5 km for extraction available. Injection team provided the injection kicker rise time (280 ns < 12e buckets) and filling pattern: 1 batch (with margin) = trise, inj+full buckets = 12empty+90bunches Possible no. of batches in max number of buckets (considering 80% filling factor) = 10667/(12+90)= 104 Total nr. of bunches = 104 x 90 = 9360 Parameter EBeam 50TeV Max. Bunches 9360* Proton/Bunch 1.1e11 Stored energy per beam 8.8 GJ *Minimum 7095 from (head-on) peak luminosity requirement of 5 x 1034 cm-2s-1

FCC horizontal dumping system Parameter βKicker 100 m σ3.3TeV@Kicker 0.25 mm βSeptum 3600 m σ3.3TeV@Septum 1.5 mm Dump line Diluting kicker Septum Collimator Kicker Collimator 500mm 25mm thick 1.5 km

FCC (horizontal) dumping system Kicker Kicker deflection: 0.133 mrad Kicker to Septum: 1050 m Opening at the septum: 2.5 cm aperture + 2.5 cm septum thickness + 10σ3.3TeV@septum+ margin = 8 cm Septum deflection: 0.9 mrad Septum to QF: 450m Septum

Abort gaps and extraction kicker functions Total space for abort gap(s) = Total nr. of buckets (100% ring circumference)– nb,min = (13351-9360) = 3991 buckets = 3991 x 25 ns ~ 100 ms  Up to 33 x 3 ms possible abort gaps Fast rise/falling time of the kickers: 1μs to 3 μs 1μs  possibility to add spare kicker modules for Field Uniformity Kicker Control corrective feedback (if erratic occurs) Short rise time reduces the lost bunches during asynchronous beam dump.  Less stress for absorbers. Flat top time from 8 μs (selective extraction of minimum 3 batches) up to 340 μs (revolution period for total abort). Field Uniformity Kicker Control

FCC dump painting the beam Dilution kickers paint the beam on the dump (spiraling out)  many for redundancy Distance d between two bunches depend on the shower behavior! d ~ 1.6mm distance spiral 3 cm [1] Rmax gives max diluter kick. Complex dump layout Different materials (liquid dump possibility) for optimal energy deposition. Segmented diluter kickers 2.5 km upstream of the dump block. Max deflection kick: 240 μrad Large beta at dump block ~ 10km  Reduction of the beam density.  What about liquid dump? [1] F. Burkart, A. Lechner

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