Speaker
Mr
Mathieu Omet
(Graduate University for Advanced Studies)
Description
In order to operate the superconducting cavities at the International Linear Collider (ILC) near their maximum gradients, cavity input (PK) and cavity loaded Q (QL) have to be controlled individually (PKQL control). In this scope a fully automated PKQL operation procedure was developed and demonstrated at cavity gradients of 16 MV/m and 24 MV/m with Q_L values of 9e6 and 3e6 at the linear electron accelerator at the Superconducting RF Test Facility (STF) at the High Energy Accelerator Research Organization (KEK). During a long-time operation with beam (6.4 mA, 615 μs) the vector sum gradient and phase stabilities during the beam transient were ΔA/A_RMS= 0.009% and Δϕ_RMS=0.009° with cavity gradient stabilities of ΔA/A_(cav1,RMS)=0.041% and ΔA/A_(cav2,RMS)=0.031%.
Since in ILC the cavity gradient spread will be±20% around 31.5 MV/m the required range of loaded Q values is 3e6 to 1e7. High loaded Q operation at QL = 2e7 with a 6.1 mA beam was demonstrated at STF. The stabilities were ΔA/A = 0.008%RMS and Δφ = 0.014°RMS.
Furthermore a near klystron operation within 5% of saturation, which is an ILC requirement, was performed at STF with a 6.2 mA beam. The stabilities were ΔA/A = 0.010%RMS and Δφ = 0.009°RMS.
An FPGA-based klystron linearization algorithm for amplitude including an in the I and Q plane circular limiter was developed, implemented, and successfully tested at New Muon Laboratory (NML) at Fermi National Accelerator Laboratory (FNAL).
Primary author
Mr
Mathieu Omet
(Graduate University for Advanced Studies)
Co-authors
Dr
Brian Chase
(FNAL)
Dr
Shinichiro Michizono
(KEK)
Dr
Takako Miura
(KEK)
Dr
Toshihiro Matsumoto
(KEK)
