An ion with a mass m and a magnitude of charge of 1e is initially at rest when it is accelerated by a potential difference of magnitude ΔV. After exiting the accelerating potential, it enters a region with a uniform magnetic field perpendicular to the ion's velocity. The ion moves in a semicircle of radius R. Next, an ion with a mass m' and a magnitude of charge of 2e is accelerated by the same potential difference and deflected by the same magnetic field. The radius of its semicircular path is R' = 4R. Find the ratio of the ion masses, m'/m.