Equilibrium electron beam parameters of the High Energy Photon Source

Abstract

Purpose The physics design of the High Energy Photon Source (HEPS) was finished after many times of iteration. Hereby, the typical equilibrium electron beam parameters corresponding to the proposed two baseline operation modes in the baseline design of HEPS are presented. Methods To compute the equilibrium parameters of the electron beam, the lattice parameters, RF parameters, and the parameters of the insertion devices (IDs) were determined first. Furthermore, it is more precise to use the full-current electron beam parameters in the estimations of the performance of the synchrotron light. Therefore, not only the single-particle dynamics but also the current-dependent collective effects need to be considered in the computations of the full-current, equilibrium parameters of the electron beam. Both analytic computations and multi-particle tracking simulations were carried out. Results The full-current, equilibrium parameters of the electron beams in the HEPS storage ring are presented in this paper. Moreover, the main beam parameters in the injector (the booster and the LINAC), corresponding to the two baseline operation modes of the storage ring, are also presented. Conclusion The typical electron beam parameters corresponding to the two baseline operation modes are given in detail in this paper.

Impedance of in-air undulator vacuum chamber in HEPS

“…Table 1 lists the three dominant HOMs that have shunt impedances over 1 MΩ/m. According to the parameter design of HEPS [20], the horizontal and vertical coupled-bunch instability threshold determined by the synchrotron radiation damping are 3.7 MΩ/m and 3.4 MΩ/m at the location of IAUs, respectively. Considering that several IAUs will be installed in the ring, the impedance can be easily exceeds the threshold if the vacuum chambers are assumed to be identical for different IAUs.…”

The high level applications for the HEPS Linac

“…In the first construction phase, 14 beamlines will be built [6]. Two operating modes, high-brightness mode and high-bunch-charge mode, are considered [7]. When the storage ring operates in the high-bunch-charge mode, the bunch charge in the ring is 14.4 nC.…”