Transverse bunch-by-bunch feedback system for time-resolved experiments at PLS-II

Abstract

A description of the upgraded bunch-by-bunch feedback system for time-resolved experiments at Pohang Light Source II (PLS-II) is provided. The bunch-by-bunch feedback system has been upgraded to increase the single-bunch current in the hybrid fill pattern of the PLS-II facility. The project is part of the SPring-8 and PLS-II collaboration. The main features of the upgrade are to employ a single 500 MHz analog-to-digital converter (ADC) instead of the previous four 125 MHz interleaved ADCs for 500 MHz rate, to replace a single-loop two-dimensional feedback with two independent one-dimensional feedback loops, to implement the tune measurement function with a single bunch, and mainly to implement single-bunch and stretcher control. The realization of a 400 mA hybrid fill pattern including a 10 mA single bunch demonstrates the precision of the upgraded bunch-by-bunch feedback system.

Wideband Diagnostics for Online Measurement of Temporal Information of Beams in a Storage Ring

“…It enables the observation of not only static structures of molecules or atoms but veiled dynamic properties of matter. Particularly, contemporary research on complex fillpatterns [1], [2] in an electron storage ring has propelled to the forefront in investigations of MHz time-resolved experiments [3] with a temporal resolution of tens of picoseconds and sophisticated techniques with a hundred femtosecond resolution [4]- [6] while serving high brightness users simultaneously. For these fast time-resolved applications, it is crucial to quantify the temporal distribution of electron bunches which has a duration of tens of picoseconds with 2 ns spacing.…”