Tagged neutron inspection system (TNIS) based on portable sealed generators S. Pesente a, * , G. Nebbia a , M. Lunardon a , G. Viesti a , S. Blagus b , K. Nad b , D. Sudac b , V. Valkovic b , I. Lefesvre c , M.J. Lopez-Jimenez c a Dipartimento di Fisica, University of Padova and INFN Sezione di Padova, Via Marzolo 8, I-35131 Padova, Italy b Department of Experimental Physics, Rud - er Bos ˇkovic ´ Institute, Bijenic ˇka c.54, 10000 Zagreb, Croatia c EADS-SODERN, 20 Av. Descartes, 94451 Limeil-Brevannes, France Available online 22 August 2005 Abstract A prototype of portable sealed neutron generator has been recently built to deliver 14 MeV neutron beams tagged by a YAP:Ce a-particle detector. In order to produce simultaneously multiple neutron beams to irradiate complex samples, a study of the position sensitivity of the a-particle detector has been performed. Possible applications in non-destructive analysis and future developments of the tagged neutron inspection system (TNIS) concept are discussed. Ó 2005 Elsevier B.V. All rights reserved. PACS: 29.25.Dz; 29.40.Mc; 82.80.JP; 89.20.Bb Keywords: 14 MeV tagged neutron beams; Non-destructive analysis 1. Introduction Non-destructive assay by fast neutrons, origi- nated in the late eighties [1,2], is a technique widely employed in several fields [3]. As an example, the detection of hidden explosives [4] is achieved by determining the elemental ratio of C, N, O nuclei from the intensity of the characteristic c-rays pro- duced in fast neutron induced reactions. This tech- nique, known as fast neutron analysis (FNA), can be used to detect explosive in landmines or to in- spect unexploded ordnance (UXO) [5]. One important limitation of the fast neutron inspection techniques is the fact that the neutron source and the c-ray detectors are placed as close as possible to the inspected object to increase the detected signal. In this situation, the signal-to- noise ratio depends on the fraction of neutrons that reach the sample and on the solid angle sub- tended by the c-ray detector. The spectra are thus 0168-583X/$ - see front matter Ó 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.nimb.2005.07.127 * Corresponding author. Tel.: +39 049 8277134; fax: +39 049 8277124. E-mail address: silvia.pesente@pd.infn.it (S. Pesente). Nuclear Instruments and Methods in Physics Research B 241 (2005) 743–747 www.elsevier.com/locate/nimb