This work deals with the absolute measurement of the neutron emission rate from a241Am-Be source by means of the manganese sulphate bath technique, which is the principal method for the absolute determination of the neutron emission rate from radionuclide neutron sources. The facility consists of a spherical container filled with an aqueous solution of manganese sulphate with a241Am-Be neutron source placed at the center. As well known, neutrons from the source, after having been thermalized by the aqueous solution, undergo neutron capture by hydrogen, manganese, sulphur, and oxygen nuclei, thus inducing a certain activity to the solution. Subsequent gamma spectrometry measurements of56Mn activity generated by55Mn neutron activation allows to determine the neutron emission rate of the source, The experimental activity has involved a variety of measurement techniques and calculation procedures, ranging from neutron reactor activation to liquid scintillation counting and Monte Carlo calculations. Neutron activations of55Mn samples has been carried out with the TRIGA reactor of the ENEA-Casaccia Research Centre, and56Mn activated samples were subsequently characterized by liquid scintillation counting, in order to obtain reference standards for the calibration of the NaI(Tl) scintillation detectors utilized to record gamma-ray emission from56Mn. Monte Carlo calculations, carried out by the MCNPX code, were required to calculate neutron transport within the sulphate manganese bath, in particular to determine55Mn neutron capture probability, and (n, α) and (n, p) concurrent reactions, as well as the neutron leakage. Such a procedure has allowed to maintaining the neutron emission rate uncertainty well below 1 %. All the measurements have been carried out at the ENEA-Casaccia Research Centre by the Italian National Institute of Ionizing Radiation Metrology. © 2014 Akadémiai Kiadó.
All Science Journal Classification (ASJC) codes
- Analytical Chemistry
- Nuclear Energy and Engineering
- Radiology Nuclear Medicine and imaging
- Public Health, Environmental and Occupational Health
- Health, Toxicology and Mutagenesis
Amendola, M., Loreti, S., Remetti, R., Capogni, M., Carconi, P. L., Cozzella, M. L., ... Pisacane, F. (2014). Experimental and Monte Carlo simulation on new manganese bath facility for absolute neutron source emission rate measurement at ENEA-INMRI. Journal of Radioanalytical and Nuclear Chemistry, 301(1), 109 - 115. https://doi.org/10.1007/s10967-014-3106-1