Construction Process with Monte Carlo of a Lead-Moderated ²⁴¹Am-Be System to Simulate the Neutron Spectrum of ²⁵²Cf

Angela Souza Gonçalves; Lunia Coelho de Almeida de Lima; Antônio Carlos Ferreira; Marcelo Marques Martins; Walsan Wagner Pereira

doi:10.15392/2319-0612.2025.2915

Authors

Angela Souza Gonçalves Institute of Radioprotection and Dosimetry , Institute of Radiation Protection and Dosimetry
Lunia Coelho de Almeida de Lima IRD , Institute of Radiation Protection and Dosimetry
Antônio Carlos Ferreira IRD , Institute of Radiation Protection and Dosimetry
Marcelo Marques Martins IRD , Institute of Radiation Protection and Dosimetry
Walsan Wagner Pereira IRD , Institute of Radiation Protection and Dosimetry

DOI:

https://doi.org/10.15392/2319-0612.2025.2915

Keywords:

Californium, Americium-Beryllium, Monte Carlo Simulation, Neutron Metrology.

Abstract

Over the years, as the use of the radionuclide ²⁵²Cf has expanded across various fields, its availability has decreased, and its cost has risen exponentially, making it the second most expensive material in the world, after antimatter. In contrast, the ²⁴¹Am-Be source is highly accessible, significantly cheaper, and has a long half-life. By employing absorber and moderator materials, neutron fields can be modified. This study presents the Monte Carlo simulation process for developing a lead-based system capable of producing a ²⁵²Cf-like neutron field from a moderated ²⁴¹Am-Be source. To match the 2.13 MeV energy of ²⁵²Cf, a spherical lead geometry with a radius of 12.56 cm was selected. The simulations achieved an average neutron energy of 2.13 ± 0.11 MeV, with conversion coefficients H*(10) and Hp(10;0) differing by only 4–6% from the reference ²⁵²Cf values. The low-cost lead moderator system suits calibration procedures and routine irradiation in neutron metrology laboratories.

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