High-gradient X-band RF technology for CLIC and beyond
Proceedings of Science Part F128556 (2016)
Abstract:
The Compact Linear Collider (CLIC) project is exploring the possibility of constructing a multi-TeV linear electron-positron collider for high-energy frontier physics studies beyond the LHC era. The CLIC concept is based on high-gradient normal-conducting accelerating structures operating at X-band (12 GHz) frequency. We present the status of development, prototyping and testing of structures for operating at gradients of 100 MV/m and beyond. We report on high-power tests of these structures using the "XBOX" test facilities at CERN and summarize experience with operation at high-gradients. We give an overview of developments for application of the X-band technology to more compact accelerators for use e.g. as X-ray FELs and in medicine.Intra-train position and angle stabilisation at ATF based on sub-micron resolution stripline beam position monitors
Proceedings of the 5th International Beam Instrumentation Conference, IBIC 2016 (2016) 348-351
Abstract:
A low-latency, sub-micron resolution stripline beam position monitoring (BPM) system has been developed and tested with beam at the KEK Accelerator Test Facility (ATF2), where it has been used to drive a beam stabilisation system. The fast analogue front-end signal processor is based on a single-stage radio-frequency down-mixer, with a measured latency of 16 ns and a demonstrated single-pass beam position resolution of below 300 nm using a beam with a bunch charge of approximately 1 nC. The BPM position data are digitised on a digital feedback board which is used to drive a pair of kickers local to the BPMs and nominally orthogonal in phase in closed-loop feedback mode, thus achieving both beam position and angle stabilisation. We report the reduction in jitter as measured at a witness stripline BPM located 30 metres downstream of the feedback system and its propagation to the ATF interaction point.Performance of nanometre-level resolution cavity beam position monitors and their application in an intra-train beam position feedback system
Proceedings of the 5th International Beam Instrumentation Conference, IBIC 2016 (2016) 352-355
Abstract:
A system of three low-Q 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 have been used to provide an input to a low-latency, intra-train beam position feedback system consisting of a digital feedback board and a custom stripline kicker with power amplifier. The feedback system has been 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 c. 220 ns. The BPMs have a demonstrated resolution of below 50 nm on using the raw measured vertical positions at the three BPMs, and has been used to stabilise the beam to below the 75 nm level. Further studies have shown that the BPM resolution can be improved to around 10 nm on making use of quadrature-phase signals and the results of the latest beam tests will be presented.The development of C-band cavity beam position monitor with a position resolution of nano meter
IPAC 2016 - Proceedings of the 7th International Particle Accelerator Conference (2016) 3149-3151
Abstract:
We developed and tested an C-band beam position monitor with position resolution of nano meter in ATF2. The C-band BPM was developed for the fast beam feedback system at the interaction point of ATF in KEK, in which C-band beam position monitor called to IPBPM (Interaction Point Beam Position Monitor). The average position resolution of the developed IPBPM was measured 10.1nm with 87% of nominal beam charge of ATF. From the measured beam position resolution, we can expect beam position resolution of around 8.8nm with nominal ATF beam charge condition. In this talk, we will describe about the development of IPBPM and the beam test results of nano meter level beam position resolution.Compact Linear Collider drive beam phase stabilization simulations
Physical Review Special Topics - Accelerators and Beams American Physical Society 18:4 (2015)
Abstract:
The drive beam phase stability is one of the critical feasibility issues of the Compact Linear Collider (CLIC) project. This paper presents a step-by-step analysis of the error propagation through the CLIC drive beam complex using realistic rf potential and beam loading amplitude functions for the drive and main beam accelerating structures. The impact of planned stabilization systems for drive beam bunch charge and longitudinal phase is simulated and the optimal specifications for such systems are calculated and discussed.