Benchmark of ACCSIM-ORBIT codes for space charge and electron-lens compensation

Abstract

Numerical simulation is a possible approach to evaluate and to understand space charge effects in the CERN injector chain for the LHC. Several codes to simulate space charge effects have been developed, and we performed a benchmark of ACCSIM [1] and ORBIT [2] in this study. The study is highly motivated since beam losses and/or deteriorations in beam quality due to space charge effects are not negligible or sometimes considerable in the complex, especially in the Proton Synchrotron Booster. We also discuss a possibility of compensation of space charge effects by applying “electron-lens”. INTRODUCTION Beam losses and/or deteriorations in beam quality due to space charge effects are not negligible or sometimes considerable in the CERN injector chain, especially in the Proton Synchrotron Booster (PSB). A lot of efforts both from experimental side [3] and analytical/simulation side [4] have been made in order to ensure the best use of injectors toward the LHC. Historically in CERN, the ACCSIM code has been employed for space charge simulation studies. A benchmark study using the ORBIT code has been started to confirm the results from ACCSIM and to profit from the advantages of ORBIT such as the capability of parallel processing. Although this kind of benchmark has been already performed [5], it is still worth to benchmark the two codes using the specific machine parameters of the PSB in which the tune spread is unusually large (up to ~0.5 for high intensity beams and more than 0.3 for LHC type beams discussed here) and overlap with the low order resonances. We also discuss the compensation of space charge effects by applying a so-called “electron-lens”. A new module for ORBIT to introduce electron-lens has been developed. Preliminary results with the module are presented and discussed.