Design and Development of Low-Level RF Digital Feedback Loop

Abstract

A controlled synchrotron light source is a specialized particle accelerator, typically accelerating electrons required for scientific and technical purposes. To energize charged particles to the final energy and to compensate the synchrotron radiation loss, RF power is used. To do so, RF cavities are used and power to RF cavities is fed using high power amplifiers (like Klystron for Indus-2 and Tetrode tube for Indus-1, at RRCAT, Indore, MP, India). With the advancement in the field of programmable logical devices and the Hardware description language, digital RF feedback control system using FPGAs is adopted for providing better flexibility, reliability and stability. In phase (I) and quadrature phase, (Q) scheme is used here for extracting the amplitude and phase information about RF signal. By processing information, the EM field inside the RF cavity has stable amplitude control loop (ACL) and phase control Loop (PCL). A new, FPGA-based, digital, low-level RF system, based on an analog I/Q modulator and demodulator, is proposed here for development.