CAS, Inst High Energy Phys, Beijing 100039, Peoples R China
4B9B is a soft X-ray beamline in Beijing Synchrotron Radiation Laboratory, the photon energy range is 10-1000ev, photon energy of the low energy branch is from 10-60eV, mainly for angle resolved photoemission spectrum. Within years operation, some experiments were limited by the poor coumt-rate. This article analyzed the shortcomings on the design of the low energy branch, introduced a new scheme of bean-dine upgrade which need to change two focusing mirrors, meanwhile the mirror parameters was calculated and tracing results of the new beandine was presented. During SR beam time, performance of the beandine was tested. after the improvement work, which shows a much more smaller focused image on sample position, and meanwhile the count-rate of experiments with upgraded are increased by more than one order. The beandine is put into use after the upgrade.