Prompt gamma-ray neutron activation analysis (pgnaa) System by using a 740 GBq 241Am-Be neutron source
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Date
2003
Journal Title
Journal ISSN
Volume Title
Publisher
National Nuclear Center of the Republic of Kazakhstan / Institute of Nuclear Physics
Abstract
A PGNAA system consisting of a 740 GBq 241Am-Be neutron source and a gamma spectrometer with a n-type Ge (REGe) detector was installed at ANRTC to measure the prompt gamma-rays produced by the interactions of thermal neutrons in the samples for the analysis of light elements such as B, P, S and Cl, and some trace elements with large cross sections (Cd, Hg, Sm, Gd, etc.).
In the irradiation system, a 55 cm diameter cylinder tank filled with water moderator comprises the neutron source placed in a polypropylene tube that was coaxially positioned in the lead rings (internal diameter: 9 cm and outer diameter: 21 cm) in order to reduce the gamma rays emitted directly from the source such as
0.0596 MeV (241Am) and 4.43 MeV (0.6 gamma per neutron) from the excited state of 13C* via the 9Be(α, n)12C reaction in the source. The moderator tank was shielded with paraffin in all sides against fast neutrons. The thickness of paraffin at the front side of the tank is 28 cm and 18 cm at other sides. The neutron irradiation
system was also shielded by using chevron lead bricks of 18 cm thickness. The background-prominent gamma rays, which is especially the 2.223 MeV gamma ray from the 1H(n,γ)2H reaction formed in hydrogenous materials used for neutron moderation was reduced remarkably in view of the permissible gamma dose for
overall irradiation room. The neutrons thermalized in moderator travel through the hole with 6 cm diameter for sample irradiations. The detector was shielded with Li2CO3 powder against thermal neutrons to avoid radiation damage and surrounded by additional lead bricks to reduce gamma-background. The measurements are
carried out for the efficiency calibration of the detector by using the standard sources. The features of the PGNAA system with an isotopic neutron source are described and its analysis capability is discussed in this paper.
Description
TENMAK D.N.3326
Keywords
Prompt gamma-ray neutron activation analysis (pgnaa), Hızlı gama ışını nötron aktivasyon analizi (pgnaa), 740 GBq 241Am-Be neutron source, 740 GBq 241Am-Be nötron kaynağı
Citation
Çetiner, M. A. ... [ve arkadaşları]. (2003). Prompt gamma-ray neutron activation analysis (pgnaa) System by using a 740 GBq 241Am-Be neutron source. The Second Eurasian Conference on Nuclear Science and Its Application : Presentations, 1.c., (s.422-431). 16-19 September 2002. Almaty : Kazakhstan.