ATOMIC CHARGE STATES IN CARBON OF 10- TO 40-MEV IONS; APPLICATION TO TANDEM ACCELERATORS

Abstract

The distribution of charge states of ions of F¹⁹, Cl³⁵, and Br⁷⁹ emerging from thin carbon foils at energies of 10 to 40 Mev have been measured. Atomic charges of 7, 9, and 11 electron units for the three elements respectively are produced at 10 Mev with an intensity of greater than 15% of the incident beam. These results show that a tandem accelerator with 10 Mv on the terminal can deliver good ion beams at the following energies (the values in parentheses require two-stage stripping resulting in a further reduction in beam intensity by a factor of 5 to 10): 80 Mev (95 Mev) F¹⁹ ions, 100 Mev (125 Mev) Cl³⁵ ions, and 120 Mev (160 Mev) Br⁷⁹ ions. The measurements show that heavy ions from a tandem accelerator can be injected into a cyclotron and stripped to give appropriate magnetic rigidity for acceleration to very high energies; for example, a 90-in. diameter magnet with a field of 14 kilogauss will yield [Formula: see text] Cl or Br ions.