Pulsed sextupole injection for Beijing Advanced Photon Source with ultralow emittance

TL;DR

This paper designs a pulsed sextupole injection system for Beijing Advanced Photon Source with ultralow emittance, analyzing two options and their effects on injection efficiency considering position-dependent dispersive effects.

Contribution

It presents the physical design and magnetic parameters of a novel pulsed sextupole injection system tailored for ultralow emittance storage rings, including optimal optical conditions.

Findings

Two injection options with different drift space configurations are feasible.

Pulsed sextupole induces position-dependent dispersive effects impacting efficiency.

Optimal optical conditions are identified for both injection configurations.

Abstract

In this paper we present the physical design of the pulsed sextupole injection system for Beijing Advanced Photon Source (BAPS) with an ultralow emittance. The BAPS ring lattice is designed in such a way that two options of pulsed sextupole injection are allowed, i.e., with septum and pulsed sextupole in different drift spaces or in the same drift space. We give the magnetic parameters of the injection system and the optimal condition of the optical functions for both options. In addition, we find that the pulsed sextupole induces position-dependent dispersive effect and causes non-ignorable effect on the injection efficiency in a storage ring with a relatively small acceptance, which should be well considered.