Nuclear Instruments and Methods in Physics Research A 506 (2003) 26–34 Performance of the ARES recoil separator for ðp; gÞ reaction measurements M. Couder, C. Angulo, W. Galster 1 , J.-S. Graulich 2 , P. Leleux*, P. Lipnik, G. Tabacaru 3 , F. Vanderbist Institut de Physique Nucl ! eaire and Centre de Recherches du Cyclotron, Universit ! e Catholique de Louvain, Louvain-la-Neuve B-1348, Belgium Received 2 December 2002; received in revised form 27 February 2003; accepted 14 March 2003 Abstract In Louvain-la-Neuve, the Astrophysics REcoil Separator (ARES), was installed to measure ðp; gÞ reactions of astrophysical interest induced by radioactive beams. ARES was coupled to the CYCLONE44 cyclotron. First tests performed with an 19 F stable beam, i.e., the Hð 19 F; 20 NeÞg reaction, are reported. r 2003 Elsevier Science B.V. All rights reserved. PACS: 29.30.h Keywords: Nuclear astrophysics; Radiative capture reactions; Recoil separators 1. Introduction The Cyclotron Research Center in Louvain-la- Neuve has a long experience in the production and acceleration of radioactive species [1]. The Astro- physics REcoil Separator (ARES), was conceived and installed in Louvain-la-Neuve as a new tool to measure cross-sections of ðp; gÞ reactions of astro- physical interest induced by radioactive beams in inverse kinematics. ARES was designed to be coupled to CYCLONE44, a new cyclotron dedi- cated to the acceleration of radioactive beams in the 0.2–0:8 MeV=amu energy range [2]. Beams from CYCLONE44 have a Full-Width at Half- Maximum (FWHM) of the order of 1% of the beam energy and an emittance of the order of 28p mm mrad (horizontal) and 16p mm mrad (vertical), which is very different from the beams from electrostatic accelerators to which recoil separators for nuclear astrophysics were pre- viously coupled [3–6]. Although the purpose of a separator is to transmit reaction products, its performance will be affected by the beam char- acteristics. Another peculiarity of ARES is the fact that the hydrogen targets used to induce ðp; gÞ reactions are polyethylene ðCH 2 Þ foils [7], instead of the windowless gas targets used in other separators. ARTICLE IN PRESS *Corresponding author. E-mail address: leleux@fynu.ucl.ac.be (P. Leleux). 1 Present address: Tohoku University, Sendai, Japan. 2 Present address: CERN, Geneva, Switzerland. 3 Permanent address: IFIN-HH, Bucharest-Magurele, Roma- nia. 0168-9002/03/$-see front matter r 2003 Elsevier Science B.V. All rights reserved. doi:10.1016/S0168-9002(03)01381-0