Abstract
Abstract
The accelerator complex of China Spallation Neutron Source
(CSNS) consists of an 80 MeV H- Linac and a 1.6 GeV proton
rapid cycling synchrotron (RCS). The beam injection is one of the
most important issues for the CSNS accelerator complex. In this
paper, the injection methods have been comprehensively studied,
including phase space painting and H- stripping. By using the
design scheme of the anti-correlated painting, the beam power has
successfully reached 50 kW. However, some difficulties have been
found in the higher power beam commissioning. In order to solve
these key problems, flexibility in the CSNS design has been
exploited to implement the correlated painting by using the rising
current curve of the pulse power supply. The effectiveness of the
new method has been verified in the simulation and beam
commissioning. By using the new method, the beam power on the target
has successfully risen to the design value. Secondly, according to
the CSNS beam commissioning experience, based on the present design
of the injection system, a new idea is proposed to perform both
correlated and anti-correlated painting in the CSNS. By adopting an
additional vertical shift bump generated by four additional
alternating current (AC) magnets in the injection region, the local
orbit can be manipulated to meet the requirement of correlated
painting. The new method can not only perform the correlated
painting, but also optimize the anti-correlated painting. The
simulation study shows that the new method works well, and both
correlated and anti-correlated painting methods are well performed.