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CLIC_DDS 1 st cell studies. Alessandro D’Elia. Updates on Vasim CERN visit. Meeting with Walter Wuensch et al. Suggested to chamfer the edges of the cell as it is mechanically not possible to have sharp edges Many discussions with Riccardo and me regarding simulations:
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CLIC_DDS 1st cell studies Alessandro D’Elia
Updates on Vasim CERN visit • Meeting with Walter Wuensch et al. • Suggested to chamfer the edges of the cell as it is mechanically not possible to have sharp edges • Many discussions with Riccardo and me regarding simulations: 1) The method of using ~ 200-300k mesh and solving zero order solution is not accurate 2) When these results were compared to HFSS10 and CST microwave, frequency was off by -30 MHz and H-field was higher by 15% i.e. 30 % more pulse temperature rise. 3) The better method is : Using surface approximation of ~2 micron and solving second order solution. • With this method now, results are consistent in HFSSv10, v12 and CST microwave. • Riccardo suggested a major change in cell geometry.
b) c) a)
Zero order soln. 180k mesh
Unphysical b) a) c)
New geometry : Riccardo Zero order slon. F=11.9682 GHz
First order soln. F=11.9897 GHz
CST HFSSv10
HFSSv10 a b
Undamped: comparison SF HFSSv10 CST HFSSv12
CLIC_G vs CLIC_DDS CLIC_G CLIC_DDS @ 4.0 mm iris radius Undamped ? Damped 1.56 1.55
The difference between and is due to the circular shape breaking when the coupling waveguide are inserted. Therefore the basic idea is to move up the coupling cell in order to minimize this effect and then, to optimize the joint curvature between the coupling and the cell to better distribute the field
H=5.0 mm H=5.0 mm H= Full width of the manifold H = 2.5 mm H = 2.5 mm Facc = 12.53 GHz Facc = 12.97 GHz
4.35 mA/V 0.6 V/m
High mesh Low mesh 2.7A/m 2.7A/m
High mesh Low mesh 2.1mA/m 1.8mA/m c b c a b a
NEXT • Check Aleksejundamped structure • Inclusion of real manifold geometry • Dipole simulations • Studying the effect of major geometric change in the manifold coupling • If everything will be successful (as we believe), review the general parameters in order to be more competitive with respect to CLIC_G (e.g. Relaxing the thermal heating and/or reviewing the beam current parameters to have higher efficiency....)