Compensation of orbit distortion due to quadrupole motion using feed-forward control at KEK ATF
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment Elsevier 895 (2018) 10-18
Abstract:
The high luminosity requirement for a future linear collider sets a demanding limit on the beam quality at the Interaction Point (IP). One potential source of luminosity loss is the motion of the ground itself. The resulting misalignments of the quadrupole magnets cause distortions to the beam orbit and hence an increase in the beam emittance. This paper describes a technique for compensating this orbit distortion by using seismometers to monitor the misalignment of the quadrupole magnets in real-time. The first demonstration of the technique was achieved at the Accelerator Test Facility (ATF) at KEK in Japan. The feed-forward system consisted of a seismometer-based quadrupole motion monitoring system, an FPGA-based feed-forward processor and a stripline kicker plus associated electronics. Through the application of a kick calculated from the position of a single quadruple, the system was able to remove about 80% of the component of the beam jitter that was correlated to the motion of the quadrupole. As a significant fraction of the orbit jitter in the ATF final focus is due to sources other than quadrupole misalignment, this amounted to an approximately 15% reduction in the absolute beam jitter.Stabilization of the arrival time of a relativistic electron beam to the 50 fs level
Physical Review Accelerators and Beams American Physical Society 21:1 (2018) 011001
Abstract:
We report the results of a low-latency beam phase feed-forward system built to stabilise the arrival time of a relativistic electron beam. The system was operated at the Compact Linear Collider (CLIC) Test Facility (CTF3) at CERN where the beam arrival time was stabilised to approximately 50~fs. The system latency was \(350\)~ns and the correction bandwidth \(>23\)~MHz. The system meets the requirements for CLIC.Stabilization of the arrival time of a relativistic electron beam to the 50 fs level
Physical Review Accelerators and Beam American Physical Society 21 (2018) 011001
Abstract:
We report the results of a low-latency beam phase feed-forward system built to stabilize the arrival time of a relativistic electron beam. The system was operated at the Compact Linear Collider (CLIC) Test Facility (CTF3) at CERN where the beam arrival time was stabilized to approximately 50 fs. The system latency was 350 ns and the correction bandwidth > 23 MHz. The system meets the requirements for CLIC.Performance of nanometre-level resolution cavity beam position monitors at ATF2
9th International Particle Accelerator Conference (IPAC'18) Joint Accelerator Conferences Website (2018)
Abstract:
A system of three lowQ cavity beam position monitors (BPMs), installed in the interaction point (IP) region of the Accelerator Test Facility (ATF2) at KEK, has been designed and optimised for nanometre-level beam position resolution. The BPMs are used to provide an input to a low-latency, intra-train beam position feedback system deployed in single-pass, multi-bunch mode with the aim of demonstrating intra-train beam stabilisation on electron bunches of charge ~1 nC separated in time by 280 ns. In 2016 the BPM resolution was demonstrated to be below 50 nm using the raw measured vertical positions at the three BPMs. New results will be presented utilising integrated sampling of the raw waveforms, improved BPM alignment and modified cavities to demonstrate a vertical position resolution on the order of 20 nm.IP feedback ground motion simulation studies for the ILC
IPAC 2017 - Proceedings of the 8th International Particle Accelerator Conference (2017) 1983-1985