A large focal plane tracking detector for low energy high mass ions.

For measurements with low energy radio active or stable beams it is important to reconstruct trajectories for ions in large solid angle spectrometers. In this paper we describe a large area (106 x 420 mm _) tracking secondary electron detectors, Se D. In Se D, the electrons emitted by an aluminized Mylar foil are captured by an electromagnetic field and focused on an electron gaseous detector to give a time and 2-D position resolution (sigma) of typically 130 nsec and 0.8 mm.