Development of a high efficiency annular detector system for RIB experiments at NSC

7Be radioactive ion beam (RIB) has been successfully extracted by the in-flight separation technique (J. Phys. G. Nucl. Part. Phys. 24 (1998) 1371) [1] using the recoil mass spectrometer (RMS) HIRA (Nucl. Instr. and Meth. A 339 (1994) 543) [2] at NSC. Many experiments measuring elastic scattering and transfer reactions using low intensity 7Be beam have been performed. To compensate for low beam intensity, a new, compact geometry, large-area, high-efficiency detector system has been developed. The detector setup consists of two position-sensitive silicon annular strip detectors, a large-area two-dimensional position-sensitive silicon detector and a transmission-type gas ionization detector. The silicon detectors give the energy as well as the position of the implanted particles and the gas ionization chamber gives the differential energy loss for particle identification.