1. 2017 CAS Erice case study: Design of a beam dumping system for FCC
Nuria
Luca
Georges-Henry
Oliver
Lorena
Vincenzo

2. 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

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

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

5. Abort gaps and extraction kicker functions
Total space for abort gap(s) = Total nr. of buckets (100% ring circumference)– nb,min = ( ) = 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

6. 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

7. Thank you for your attention!