Calculation of the coupled betatron motion introduced by cooler's solenoids of CSRm

TL;DR

This paper investigates how uncompensated solenoids in an electron cooler cause coupled betatron motion in the ion beam of CSRm, and introduces a new method to calculate the resulting beam envelopes.

Contribution

A new method is proposed to calculate coupled beam envelopes caused by uncompensated cooler solenoids in CSRm.

Findings

Coupled transverse motion is induced by uncompensated solenoids.

A novel calculation method for coupled beam envelopes is developed.

Results show the impact of solenoid compensation on beam dynamics.

Abstract

Several solenoids are usually installed in electron cooler device to guide the motion of the electron beam in the cooler. However, the solenoids also have influence to the ion beam in the cooler storage ring. The transverse motion of the ion beam in storage ring will become coupled, if the solenoids installed in the electron cooler are not compensated perfectly. In this paper, the coupled transverse motion due to the uncompensated cooler's solenoids of CSRm (The main storage ring in the IMP, Lan Zhou, China) is studied, and the coupled beam envelopes are calculated by a new method.