A 2.3 GHz BANDWIDTH STRUCTURE FOR CLIC_DDS Vasim Khan

Spectral function 96 cells 4-fold interleaving 192 cells 8-fold interleaving 24 cells No interleaving 48cells 2-fold interleaving

96 cells 4-fold interleaving 192 cells 8-fold interleaving 24 cells No interleaving 48cells 2-fold interleaving ∆fmin = 65 MHz ∆tmax =15.38 ns ∆s = 4.61 m ∆fmin = 32.5 MHz ∆tmax =30.76 ns ∆s = 9.22 m ∆fmin = MHz ∆tmax = ns ∆s = m ∆fmin = 8.12 MHz ∆tmax =123 ns ∆s = m

Corrected formula for effective pulse length [1] Unloaded [1] A. Grudiev, CLIC-ACE, JAN 08 Allowed limit = 260 MV/m Allowed limit = 56 K Results based on only 3 cell simulations.

7 cell simulations.

ParametersCLIC_G (Optimised) [1,2] CLIC_DDS (Non-optimised) Bunch space (rf cycles/ns)6/0.58/0.67 Limit on wake (V/pC/mm/m) Number of bunches312 Bunch population (10 9 ) Pulse length (ns) Fill time (ns) Pin (MW) Esur max. (MV/m) Pulse temperature rise (K) RF-beam-eff (for corrected pulse length: Eff.=26.6%) [1] A. Grudiev, CLIC-ACE, JAN 08 [2] CLIC Note 764 Updated

Considering 8 fold interleaved structure ParametersStructure # 1Structure # 8 f1, f24 (GHz) , , ∆f (GHz) a1, a24 (mm)4, , 2.3 /λ0.13 N (x10 9 particels/bunch)

Pin=76.5 MW Structure # 1

73.5 MW Structure # 8

Sum RMS wake-field of an 8-fold interleaved structure Amplitude wakeSumwake wake

Cell # Random error in f (MHz) Cell # f (GHz) Random error in frequencies +/- 3.5 MHz

8 fold interleaved structure Random error in frequencies +/- 3.5 MHz

Amplitude wakeSumwake wake

Dipole simulations with fillet and high mesh Cell # 13 Cell # 24 Geometry with fillet, solution is converged and average mesh = 400 k No fillet, solution is not converged (only 3 passes )and average mesh = 50 k Geometry with fillet, solution is converged and average mesh = 400 k No fillet, solution is not converged (only 3 passes )and average mesh = 40 k Cell # 1 No fillet, solution is not converged (only 3 passes )and average mesh = 50 k Geometry with fillet, solution is converged and average mesh = 400 k

24 cell structure Dashed curve : Unloaded condition Solid curve : Beam loaded condition ∆T (K) Pin (MW) Eacc (MV/m) Esur (MV/m) Allowable limit on Esur Avg. Eacc Allowable limit on ∆T

8 – fold interleaving Structure # 1 Dashed curve : Unloaded condition Solid curve : Beam loaded condition ∆T (K) Pin (MW) Eacc (MV/m) Esur (MV/m) Allowable limit on Esur Avg. Eacc Allowable limit on ∆T

8 – fold interleaving Structure # 8 Dashed curve : Unloaded condition Solid curve : Beam loaded condition ∆T (K) Pin (MW) Eacc (MV/m) Esur (MV/m) Allowable limit on Esur Avg. Eacc Allowable limit on ∆T