Characteristic of Beam Current of Stripper Gas on 3 MV Tandem Accelerator

The experiment for determining the characteristic of beam current of stripper gas and calculation the most probability of charge state and the energy loss of ions caused by the stripper gas of 3 MV tandem accelerator has been done at JAERI Takasaki Japan. Stripper gas in a tandem accelerator is used to exchange the negative ions produced by ion source into positive ions. In this experiment, nitrogen gas was used as stripper gas, while helium and hydrogen were used as ions beam. The result of the experiment is the optimum pressure of gas stripper at 1 MV are 7.5 x 10-7 Torr (H+), 1.8 x 10-7 Torr (He1+), 5.3 x 10-7 Torr (He2+); at 2 MV are 10 x 10-7 Torr (H+); at 2.5 MV are 2.5 x 10-7 Torr (He1+), 9.0 x 10-7 Torr (He2+), and at 3 MV are 13 x 10-7 Torr (H+). The result of calculation of most probable charge state are He = 2, N = 3, P = 3, Fe = 3, and Au = 3. The result of calculation of ion energy loss caused by stripper gas are 0.8 keV for He, 7 keV for N, 11 keV for P, 12 keV for Fe, and 14 keV for Au. The result of the experiment and calculation data are used for the reference of operations setting of tandem accelerator. (author)