Yield estimation of radionuclides from 6,7Li-induced reactions: A comparative analysis for 97,95Ru

The article reports the production yields of the medically relevant Ru radionuclides and other co-produced radionuclides from 6,7Li-induced reactions on 93Nb target within the 20-45 MeV energy range. The residues were measured employing the activation technique followed by the offline γ-spectroscopy. Statistical model calculations using EMPIRE3.2.2 code are employed to assess the optimized nuclear model parameters and production mechanisms of the residues. As an outcome, new data from 6Li reaction suggests 9720 MBq/C of thick target yield (TTY) for the production of 95Ru with minimal impurities. While 7Li reaction may be relied upon for producing 97Ru, yielding 813 MBq/C TTY within the studied energy range.

Can we reach suitable 161Tb purity for medical applications using the 160Gd(d,n) reaction?

Terbium is a chemical element that has several radioactive isotopes with suitable physical characteristics to be used in medical applications either for imaging or for therapy. This makes terbium a promising element to implement the theranostic approach. For therapeutic applications, 161Tb (T1/2 = 6.89 d) is suitable for targeted β-therapy. The main production route is through neutron capture reaction in nuclear reactors. In this work, we explored an alternative production route, the 160Gd(d,n)161Tb reaction. We have measured its production cross-section as well as those of possible co-produced contaminants, with a special focus on 160Tb (T1/2 = 72.3 d). To achieve this, cross-section measurements were made from natural gadolinium target. Production yields of 10.3 MBq/μA/h for the 161Tb and 1.5 MBq/μA/h for the 160Tb were obtained at 20 MeV. A161Tb radionuclidic purity of 86% was achieved over the 8 MeV-20 MeV energy range. The co-production of other terbium isotopes limits the interest of using higher energies. Based on the limited purity of 161Tb using the 160Gd(d,n)161Tb reaction, we conclude that it is not a production route suitable for medical applications. Although, this may be reconsidered when mass separation technique with high efficiency will be available.

Cryomilling of Isotope-Enriched Ti Powders for HIVIPP Deposition to Manufacture Targets for Nuclear Cross Section Measurement

The realization of isotopically enriched Ti targets for nuclear cross-section measurements requires particular attention, from the starting material preparation up to the deposition technique. In this work, a cryomilling process was developed and optimized, aimed at reducing the size of ^49,50Ti metal sponge as provided by the supplier (size up to 3 mm), to the optimal size of 10 µm, to fit the High Energy Vibrational Powder Plating technique used for target manufacturing. The optimization of the cryomilling protocol and the HIVIPP deposition using ^natTi material was thus performed. The scarce amount of the enriched material to be treated (about 150 mg), the need to obtain a non-contaminated final powder and a uniform target thickness of about 500 µg/cm² were taken into account. The ^49,50Ti materials were then processed and 20 targets of each isotope were manufactured. Both powders and the final Ti targets produced were characterized by SEM-EDS analysis. The amount of Ti deposited was measured by weighing, indicating reproducible and homogeneous targets, with an areal density of 468 ± 110 µg/cm² for ⁴⁹Ti (n = 20) and 638 ± 200 µg/cm² for ⁵⁰Ti (n = 20). The uniformity of the deposited layer was also confirmed by the metallurgical interface analysis. The final targets were used for the cross section measurements of the ⁴⁹Ti(p,x)⁴⁷Sc and ⁵⁰Ti(p,x)⁴⁷Sc nuclear reaction routes aimed at the production of the theranostic radionuclide ⁴⁷Sc.