EM Simulation of wakes in BSRT beampipe with extraction mirror
description
Transcript of EM Simulation of wakes in BSRT beampipe with extraction mirror
EM Simulation of wakes in BSRT beampipe with extraction mirror
Tool: Time domain solver of ACE3P Suite.Crosscheck with CST Particle Studio.
Andriy Nosych / CERN BE-BI-QPImpedance meeting / 25 June 2012
Simplified BSRT model is considered
Mirror front
(BSRT complete assembly)
Beam
22 mm
Mirror back (most likely coated)
Silicon
Excitation:
Single bunch with Gaussian charge distributionCharge = 1.7e-8 CBunch length: 0.3 m / 1 ns / [-4s, 4s]s = 40 mm / 130 picosecondsBunch transverse size: point
Wake potential along beam axis
Simulated mirror modifications @ ACE3P
Silicon mirror (eps = 11.9,el.cond=2.5e-4)
Silicon + coated mirror (by putting an electric boundary on back surface)
Stainless-steel mirror
Simulated mirror modifications @ ACE3P
Coated/Steel mirror have a resonant mode at around 658-670 MHz
Harmonics?
Silicon mirror (eps = 11.9,el.cond=2.5e-4)
Silicon + coated mirror (by putting an electric boundary on back surface)
Stainless-steel mirror
Crosscheck with CST Particle Studio (coated mirror sample)
Full assembly VS. Simplified assembly
Full assembly peak at: 640 MHzSimplified peak at: 655 MHz
First test run with 3-bunch train (Steel mirror sample) @ ACE3P
Peak at 670 MHz
E-field Magnitude @ ACE3P + E-field probe along white line (mirror edge)
“Old” simplified mirror support
“New” complete mirror support assembly
Mirror in
Beam-mirror: 22 mm
Mirror out
Beam-mirror: 50 mm
“Ferrite” ring (made of Steel so far, can not simulate ferrite)
Additional cavities behind mirror support.
Full electric contact between washer and body. Thus no vacuum considered behind washer.
CONCLUSIONS:
With a complete model of a mirror support, the resonating mode frequency shifts to 600 MHz.
No big difference between resonances with the mirror
“in” and “out”.
UPDATE