NUCLEAR PHYSICS IN-BEAM COMMISSIONING OF A RECOIL MASS SPECTROMETER T.B. SAVA 1,3 , D. BUCURESCU 1 , G. C ˘ ATA-DANIL 1,2 , I. C ˘ ATA-DANIL 1 , D. DELEANU 1 , D. FILIPESCU 1 , D. GHIT ¸ ˘ A 1 , T. GLODARIU 1 , M. IVAS ¸CU 1 , N. M ˘ ARGINEAN 1 , R. M ˘ ARGINEAN 1 , C. MIHAI 1 , V. MOS ¸U 1 , A. NEGRET ¸ 1 , G. PASCOVICI 4 , S. PASCU 1 , L. STROE 1 , N. V. ZAMFIR 1 1 Department of Nuclear Physics, National Institute for Physics and Nuclear Engineering “Horia Hulubei”, Atomis ¸tilor 407, RO-077125, POB-MG6, M˘ agurele-Bucharest, Romania, EU E-mail: tiberiu@tandem.nipne.ro 2 Faculty of Applied Sciences, University ”Politehnica” of Bucharest, Splaiul Independent ¸ei 313, RO-060042,Bucharest, Romania, EU 3 Faculty of Physics, University of Bucharest, Atomis ¸tilor 405, RO-077125, M˘ agurele-Bucharest, Romania, EU 4 Institute for Nuclear Physics, University of Cologne, DE-50937 Cologne, Germany, EU Received February 2, 2011 A review of electromagnetic separation for the low-energy fusion-evaporation recoils produced on a thin 12 C target by a 44 MeV beam of 19 F delivered by the IFIN- HH tandem accelerator is presented. The mass, velocity, energy and angular distribu- tions of these recoils were studied using a spectrometer composed of a velocity selector (Wien filter), a 60 ◦ analyzing dipole magnet and two magnetic quadrupole doublets. Focal plane secondary beam diagnostic was performed using a 4×2 matrix of photo- voltaic Si-PIN detectors and a pseudo-time of flight (ToF) technique using 5 MHz RF from the beam pulsing system. A complete description of the experiment preparations, running and the results interpretation is made. Key words: recoil spectrometer, electromagnetic separation, low energy recoils. 1. INTRODUCTION Studying nuclei away from the valley of stability is a central theme in present nuclear structure physics. For proton-rich nuclei, fusion-evaporation reaction involv- ing stable beams and targets is a usual technique to access isotopes towards the proton drip line. For a proper selection and identification of such isotopes a residue detector is very advantageous. The present paper presents a type of instrument that is used for separating and analyzing recoils resulted from fusion-evaporation reactions produced with ion beams delivered by the Bucharest FN Tandem accelerator [1]. For these recoils we were interested in determining their mass distribution, evaluating velocity distribu- tion using a Wien filter [2], energy spectra and some aspects of angular distribution properties. The test case is represented by the slightly inverse kinematics reaction of 19 F (44 MeV) bombarding a 200 μg/cm 2 12 C foil. The aim of the experiment (c) RJP 56(Nos. 9-10) 1094–1107 2011 Rom. Journ. Phys., Vol. 56, Nos. 9-10, P. 1094–1107, Bucharest, 2011