摘要：HIAF Fragment Separator(HFRS)is the only beam line that connected Booster Ring(BRing)and Spectrometer Ring(SRing)in the HIAF and used to transfer both the primary ion beams and secondary radioactive *** beam passed once in HFRS so low vacuum degree was *** HFRS connects with extremely high vacuum systems of BRing and SRing,so it is related to the gradual transition of pressure,the vacuum pressure can’t be too *** into account the above situation,the vacuum degree of HFRS should be better than 1×10^(−7)mb.