A position-sensitive transmission time detector

A position-sensitive channel plate time detector for heavy ions was developed. Secondary electrons from a thin carbon foil (15 x 50 mm2) are accelerated in an electric field and then deflected by 900 onto a channel plate with a position-sensitive anode using an electrostatic mirror. This arrangement allows the foil to be perpendicular to the particle trajectories. The time resolution was found to be 150 ps, the position resolution 1.3 mm (fwhm). The device serves as start detector for the time-of-flight measurement through a magnetic spectrometer. From the position information the angle of incidence into the spectrometer is derived. (orig.)