Abstract: SET-UP OF A SMALL INSTRUMENT USING TXRF WITH HIGH SENSETIVITYTian Yuhong;Wang Ruiguang;Wang Zhiguo;Liu Kai;Zheng Suhua（Department of Physics,Yantai University,Yantai 264005）1）（Institute of Modern Physics, the Chinese Academy of Sciences,Lanzhou 730000)Abstract:An analytical instrument using total reflection X-ray fluorescence (TXRF）technique with a small size and high sensetivity is developed．The X－ray tubes with Cu,Mo and W anodes are employed respectively as exciting source.Two double total reflection units with special optical path are designed．Minimum detection limits（MDL）at 0. 007ng,0．004ng and 0．08ng are reached in the condition of 6mA exciting beam and 25kV Cu anode,45kV Mo anode and 50 kV anode respectively.Keywords:Two double total refelection Two exciting source Analytical instru ment using TXRF