The Separation Performance Research Of Superconducting Fragment Separator

This paper introduces the design philosophy and feasibility analysis of Superconducting fragment separator HFRS in High Intensity Heavy-ion Accelerator Facility(HIAF).HFRS is the most significant facility to investigate the radioactive physics in HIAF.HFRS is an in-flight fragment separator system,which contains many unique features,such as large magnetic rigidity,large acceptance,large magnet aperture,high momentum resolving power and so on.HFRS uses the Bρ-ΔE-Bρmethod to separate the exotic nuclei produced by projectile fragmentation or fission,which are used to investigate the high precision in-ring experiments or out-ring experiments.HFRS is a two-stages magnetic system containing Pre-separator and Main-separator,each of which is equipped with achromatic degrader system.This paper is mainly to investigate the separation performance of HFRS.There are two programs,MOCADI and GICOSY,used to simulate the purification and transmission efficiency of fragment.First of all,we propose the influence of degrader on separation performance.The degrader improves the purity of particles with bad transmission effect of secondary reactions,which makes the number of particles decrease.Therefore,it is important to select the best thickness of the degrader.The separation effect and purification of single-stage separator and two-stages separator are compared with each other.According to the simulation results,the separation effect of two-stages separator is better than that of single-stage separator.At same time,the effect of secondary reaction on the degrader is reduced sharply,but the separation efficiency is improved remarkably.Therefore,it is necessary for HFRS to take the plan of two-stages separator.At last,we simulate the purification of fragment in projectile fragmentation and fission with one degrader stage and two degraderstages.The simulation results show that HFRS has good achromatic and focusing properties,and it can efficiently isolate and purify light nuclides from fragmentation and a certain separation effect of heavier nuclides.The fission separation performance of HFRS is not as good as fragmentation fragments.