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We have commissioned the digital Low Level RF (LLRF) system for storage ring RF at Advanced Light Source at Lawrence Berkeley National Lab (LBNL). The system is composed of 42 synchronous sampling channels for feedback control, diagnostics, and interlocks. The closed loop RF amplitude and phase stability is measured as < 0.1% and < 0.1 degree respectively, and the real-time machine protection interlock latency is measured < 2.5 microsecond. We have also developed PLC-FPGA-EPICS interfaces to support system configurations between hybrid operation modes using two klystrons driving two RF cavities at 500MHz resonance frequency. The deployed LLRF system has been operating since March 2017.
The PIP-II accelerator is a proposed upgrade to the Fermilab accelerator complex that will replace the existing, 400 MeV room temperature LINAC with an 800 MeV superconducting LINAC. Part of this upgrade includes a new injection scheme into the booster that levies tight requirements on the LLRF control system for the cavities. In this paper we discuss the challenges of the PIP-II accelerator and the present status of the LLRF system for this project.
This paper presents a conceptual approach to phase modulation of the cavity field in storage ring RF systems. An implementation of the concept on Dimtel low-level RF controllers is also presented. The method is illustrated with the test results from a cavity simulator, as well as an electron storage ring KARA.
The first phase of the MYRRHA (Multi-purpose hYbrid Research Reactor for High-tech Applications) project, MINERVA, was launched in September 2018. Through collaboration with the SCK-CEN, IN2P3 laboratories take in charge the developments of several parts of the accelerator, including a fully equipped Spoke cryomodule prototype and a cold valves box. This cryomodule will integrate two superconducting single spoke cavities operating at 2K, the RF power couplers and the cold tuning systems associated. For control and regulation purpose, a mTCA LLRF system prototype is being implemented and will be presented here alongside with the hardware, VHDL and EPICS developments that aim to fulfil MYRRHAs ambitious requirements.
This volume contains contributions presented at LLRF2019: the 9th Low-Level RF Workshop held in Chicago, USA on September 29 - October 3, 2019.
The use of existing linacs, and in particular light source injectors, for free-electron laser (FEL) experiments is becoming more common due to the desire to test FELs at ever shorter wavelengths. The high-brightness, high-current beams required by high-gain FELs impose technical specifications that most existing linacs were not designed to meet. Moreover, the need for specialized diagnostics, especially shot-to-shot data acquisition, demands substantial modification and upgrade of conventional linacs. Improvements have been made to the Advanced Photon Source (APS) injector linac in order to produce and characterize high-brightness beams. Specifically, effort has been directed at generating beams suitable for use in the low-energy undulator test line (LEUTL) FEL in support of fourth-generation light source research. The enhancements to the linac technical and diagnostic capabilities that allowed for self-amplified spontaneous emission (SASE) operation of the FEL at 530 nm are described. Recent results, including details on technical systems improvements and electron beam measurement techniques, will be discussed. The linac is capable of accelerating beams to over 650 MeV. The nominal FEL beam parameters used are as follows: 217 MeV energy; 0.1-0.2% rms energy spread; 4-8 um normalized rms emittance; 80-120 A peak current from a 0.2-0.7 nC charge at a 2-7 ps FWHM bunch.