sketching basic kicker system parameters w. bartmann, t. fowler, b. goddard, t. kramer
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Sketching Basic Kicker System Parameters
W. Bartmann, T. Fowler, B. Goddard, T. Kramer
Motivation• Increase number of kicker modules such that each
module only contributes a kick below system endangerment thresholds.
• Investigate a segmented system to: • Limit beam perturbations by pre-fired kicker(s)• Subsequently avoid asynchronous beam abort.• Limit the consequences of missing modules
during beam extraction. • Ease the feasibility of (several) redundant
modules (hot spares).
Summary of 1st assumption (last meeting)
• Total required FCC MKD kick: 0.15mrad (25T.m) (for layout with Quad-window)
• Available beam line length: ~100m; b=500m• Max. acceptable kick on circ. beam: 2.75σ → 0.75µrad• 200 modules are needed for an individual module
kick of <0.75µrad.
Probably too high – should be reduced to 1σ to stay on the safe side.
Reduce to 150m.
Relation between max. acceptable kick, max. kick per module and beta
0 100 200 300 400 500 600 700 800 900 10000
Possible system configuration
• Assuming design based on LHC MKD like magnet.• For b=150m and max. perturbation of 1s a max. kick of 0.52µrad/module is allowed.• Total system would consist of 290 +10 spares = 300 modules. • B.dl = 0.0862T.m per module; module kick: 0.517µrad• Module length 30cm -> 87m mag. length; total physical length ~125m• Module length 26cm -> 75.4m mag. length; total physical length ~112m
1 6 7 12
Reference for assumptions: LHC MKD system
Distances between magnets:• Chamber head: 46 mm (LHC MKD)• Usually 120 mm between magnets but: • 400 mm for vacuum pump between every 2nd magnet
(~3 m) and 275 for valve every 5th magnet (~8m)
Kept the same as 1st assumption - to be evaluated with vacuum specialists.
• B-field: 0.29 T • Inductance L for squared aperture of 36mm: Lm= 0.4µH• Current: I= 8.3 kA• Required Voltage: 5.25 kV (t.b.c) • Generator main capacitance: 1.02 µF
Parameters (per module)
B.dl [T.m] 0.0862
k [µrad] 0.517
Length [mm] 300
Aperture (h) [mm] 36
Still to be done• Basic design of pulse generator
• Switch and main capacitor circuit • Freewheel circuit• Droop compensation ( 350µs!) • Switch trigger circuits
• Integration aspects• 3D Magnet size • Vacuum System • Switch (stack) size • Capacitor sizes
• Etc …