Feasibility study of Samarium-153 production by secondary fast neutron bombardment

As a beta emitter, samarium-153 (Sm-153) has been used in palliative cancer therapy. One of the widely employed methods to produce Sm-153 is by irradiating enriched Sm-152 target with thermal neutrons via ¹⁵²Sm(n,γ)¹⁵³Sm nuclear reaction. In this work, Sm-153 radioisotope production is theoretically proposed using secondary fast neutrons bombarded to enriched Eu-153 target via ¹⁵³Eu(n,p)¹⁵³Sm nuclear reaction. The secondary fast neutron flux calculation was performed using the PHITS 3.20 code, in which, in the simulation, a 10-MeV proton beam was bombarded to a 0.3 mm thick primary titanium (Ti) target to generate secondary fast neutrons. The fast neutrons were then bombarded to the enriched Eu-153 target to produce Sm-153. Based on the PHITS simulation results, the total fast neutron flux generated from the 10-MeV proton bombarded Ti target was 2.16x10¹¹ n/cm²s. With such a neutron flux, Sm-135 radioactivity yield was estimated to be 3.19 kBq/µAh. The most possible beta-emitting radioisotope impurity generated during Sm-153 production was Eu-154, whereas the most possible stable isotope that could be produced during Sm-153 production was Sm-152. This theoretical study highlights that secondary fast neutrons as a result of 10-MeV proton bombardment can be used to produce Sm-153 radioisotope.