Speaker
Description
Fast Neutron-induced Gamma-ray Spectrometry (FaNGaS)
Niklas Ophoven1,2*, Zeljko Ilic2, Eric Mauerhofer1, Tsitohaina H. Randriamalala1, Egor Vezhlev1, Christian Stieghorst4, Zsolt Révay4, Thomas Brückel1,3, Jan Jolie2, Erik Strub2
1Jülich Centre for Neutron Science, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
2Mathematisch-Naturwissenschaftliche Fakultät, Universität zu Köln, 50923 Cologne, Germany
3Lehrstuhl Für Experimentalphysik IVc, RWTH Aachen University, 52056 Aachen, Germany
4Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Lichtenbergstraße 1, 85748 Garching, Germany
*E-mail: n.ophoven@fz-juelich.de
Keywords: Inelastic scattering, Fast neutron, Cross section, Gamma ray, Detection limit
Prompt Gamma Neutron Activation Analysis (PGNAA) based on cold or thermal neutron capture is a powerful technique for non-destructive elemental analysis of small and thin samples. However, due to limited penetration and attenuation effects, PGNAA is not suited for a precise investigation of large objects. The feasibility to analyse large samples by measuring prompt gamma rays from fast-neutron-induced reactions was already demonstrated several decades ago [1]. The FaNGaS (Fast Neutron-induced Gamma-ray Spectrometry) instrument, installed at Heinz Maier-Leibnitz Zentrum (MLZ) in 2014, advances this technique in nuclear analytical chemistry and makes it available for a broad community of industry and research [2-8]. Using the intense fission neutron beam delivered by the research reactor FRM II (Forschungs-Neutronenquelle Heinz Maier-Leibnitz) to investigate fast-neutron induced prompt gamma-ray emission, it offers new possibilities for the chemical analysis of large or small samples as a complementary method to conventional thermal- or cold-neutron based PGNAA. The predominant reaction channel of fast neutrons at FaNGaS is the (n,n’γ) inelastic scattering reaction, currently with only one existing database: the “Atlas of Gamma-rays from the Inelastic Scattering of Reactor Fast Neutrons”, published in 1978 by Demidov et al. [9]. This data compilation is valuable and a relational database has been recently developed based on this Atlas [10]. However, it was yet never validated and previous measurements with FaNGaS show the need for a critical and meticulous validation [3-6,8]. Apart from building up a comprehensive catalogue of (n,n’γ) reactions another main objective is a continuous optimization of the instrument to achieve a further peak-to-background reduction.
In this talk the experimental set-up and technical specifications of FaNGaS will be given. Relative intensities and partial gamma-ray production cross sections of fast-neutron-induced prompt gamma rays derived from the measurement of various elements will be presented along with literature comparisons.
References
[1] Schrader CD, Stinner RJ (1961). J Geophys Res 66:1951-1956
[2] Randriamalala TH et al. (2016). Nucl Instrum Methods A 806:370-377
[3] Ilic Z et al. (2020). J Radioanal Nucl Chem 325:641-645
[4] Mauerhofer E et al. (2021). J Radioanal Nucl Chem 331:535-546
[5] Mauerhofer E et al. (2022. J Radioanal Nucl Chem 331:3987-4000
[6] Ophoven N et al. (2022). J Radioanal Nucl Chem 331:5729-5740
[7] Bouat S et al. (2021). Nondestruct Test Evaluation 37:1-13
[8] Ophoven N et al. (2023). J Radioanal Nucl Chem (under review)
[9] Demidov A et al. (1978). Atomizdat, Moscow
[10] Hurst AM et al. (2021). Nucl Instrum Meth A 995:165095
