Incomplete fusion reaction producing Pa nuclides in the ²³²Th + ⁷Li reaction

The Np-237 (t(1/2) = 2.1 x 10(6) y) nuclide is produced in nuclear facilities. Its investigation is relevant to earth sciences as concerns environmental pollution and material circulation. We expected that this nuclide should be able to be analyzed by mass spectrometry with a neptunium tracer as a spike, such as that of Np-236g (t(1/2) = 1.5 x 10(5) y). Our research group has collected fundamental data for cross-sections of the Th-232 + Li-7 reaction for use in spike production. In addition to the complete fusion reaction, incomplete fusion also occurs, especially in the reaction of Li-7, which splits into a and t, and only a part of the projectile fuses with the target nucleus. In this study, the excitation functions of Pa isotopes, as products of the incomplete fusion reaction, were measured. The reaction mechanism is discussed by comparing the experimental values with those calculated using the EMPIRE code. In addition, we investigated the effect of incomplete fusion reaction on the entire reaction.