Ion Optics Simulation for Fragment Separator

We have developed a Monte-Carlo simulation code for unstable-nuclear beam experiments using a fragment-separator. This code primarily aims at calculating beam traces in the fragment separator BigRIPS and ZeroDegree Spectrometer (ZDS) at RIBF(RIKEN RI-Beam Factory). This code uses externally given transfer-matrices of ion optics such as an output of COSY Infinity[1]. We have applied this code to recent campaign of experiments using $^{48}$Ca at 345MeV$/$u as primary beam. In the experiments, two modes of ion optical settings , namely ``Standard'' and ``High Brho'' modes were used. The former is an ordinary used starndard setteing, which has a limit in the maximum rigidity ($B\rho<9.2$Tm). On the other hand, the ``High Brho'' setting has been developed for a secondary beam with higher rigidity, such as for very neutron rich nuclei $^{22}$C (A/Z=3.67). In this talk, we compare properties of these two optics settings and evaluate beam traces, emittances, and transmissions.\\[4pt] [1] K. Makino, M. Berz Nucl. Instr. Meth. A 558 (2005)