Abstract: ISOTOPIC EXCHANGE OF CARRIER IODINE WITH RADIOIODINE BY CCl_4 EXTRACTION OF IODINEYANG WEIFAN；LI ZONGWEI；SUN XIURONG MO WANTONG；ZHAO ZHIZHENG；XIE XIUJUN QIN ZHI；ZHANG LI；WU DINGOING（Institute of Modern Physics，Academia Sinica，Lanzhou，730000）ABSTRACT The isotopic exchange of the radioiodine with the carrier iodine is investigated by CCl_4extraction of iodine formed in the interactopn of 47MeV／u ~(12)C ions with ~(133)Cs.The radioio-dine is separated from the other reaction products by the CCl_4 extraction of iodine with thecarriers I~- IO and IO．The iodine is preciptated as AgI for weighing and counting. Theresults are shown that the complete exchange of radioiodine with the carrier iodine can becarried out using a procedure which consists of the oxidation of I~- to IO by NaClO in an aL-kaline solution， the reduction of the IO to I_2 with hydroxylamine hydrochloride（NH_2OH·HCl）in the acidic solution and the extraction of I_2 with CCI_4. The exchange rates of the I~-（I°），IO and IO are 85％， 92％ and 94％，respectively. Key words Isotopic exchange Extraction Cross section~(12)C ion