  The fusion cross section of 3He(3He,2p)4He at a center of mass energy of 30
to 50 keV has been measured by using helium-3 doubly ionized beam at a
low-energy high current accelerator facility, OCEAN. Free from molecular
interference in the beam, the measurement determines the astrophysical S-factor
with better statistical and systematical errors than previous data. By using
singly and doubly charged helium-3 ions the facility envisages to provide the
data from high energy to Gamow energy regions.
