Recoil separator ERNA:: acceptances in angle and energy

For improved cross-section measurements of the reaction C-12(alpha,gamma) O-16 in inverted kinematics, a recoil separator ERNA is developed at the 4 MV Dynamitron tandem accelerator in Bochum to detect directly the O-16 recoils with high efficiency. Due to the emission of the capture gamma-rays, the kinematically forward directed O-16 recoils are described by an angle and energy spread. Thus, the acceptances in angle and energy of ERNA must cover these spreads in order to extract reliable cross-section values. We report on such acceptance measurements over the energy range 0.7-5.0 MeV, using an O-16 pilot beam. (C) 2003 Elsevier B.V. All rights reserved.