The vertical drift chamber as a high resolution focal plane detector for heavy ions

Abstract

A vertical drift chamber in the focal plane of a magnetic spectrometer has been tested with 12C(129 MeV), 14N(176 MeV) and 16O (140 MeV) ions. An experimental position resolution of ≤ 0.5 mm was measured,corresponding to an intrinsic detector resolution of about 0.1 mm (fwhm). The angle of the ion trajectory with respect to the focal plane was measured to within ∼ 10 mrad, which corresponds to an intrinsic detector resolution of about 7 mrad. The angle measuring capability of the counter permits the measurement of angular distributions across the spectrometer opening and the correction of the counter data for magnet aberrations. Details of the electronics and gas handling systems and the detector performance with heavy ions are presented.