Measurement and analysis of excitation functions of the residues from ${}^{12}\mathrm{C}+{}^{89}\mathrm{Y}$: A major production route for ${}^{97}\mathrm{Ru}$

Background: ${}^{97}\mathrm{Ru}$, a good hepatobiliary agent, is used in delayed investigations, diagnostic and therapeutic purposes, due to its favorable physicochemical properties. Various experimental studies have been carried out to investigate its production and chemical separation. However, in the interest of the subject, a lot of investigation is still required to identify the suitable routes for its optimum production, particularly for heavy-ion reactions, and to understand the reaction mechanisms.

Purpose: Measurement and analysis of excitation function of the residues from the ${}^{12}\mathrm{C}+{}^{89}\mathrm{Y}$ reaction at the low-energy region and to estimate the cross-section of ${}^{97}\mathrm{Ru}$ expected to be produced through the direct channel, and indirectly via the decay of its short-lived precursors ${}^{97g,97m}\mathrm{Rh}$.

Method: Thin ${}^{89}\mathrm{Y}$ foils backed by aluminium were bombarded by the ${}^{12}\mathrm{C}^{6+}$ beam within 40–75 MeV energy range. The excitation functions of the residues have been measured with the help of off-line $\gamma$-ray spectroscopy. Experimental cross-sections are compared with the various reaction models to understand the reaction mechanism involved in the production of residual radionuclides.

Results: The measured cross-sections of ${}^{97}\mathrm{Ru}, {}^{98,97m+g,96}\mathrm{Rh}, {}^{96,95,94,93}\mathrm{Tc},$ and ${}^{93m}\mathrm{Mo}$ radionuclides show reasonably good agreement with the calculations based on the equilibrium (EQ) and preequilibrium (PEQ) models. The contribution of PEQ emissions is observed in the $3n$ and $\alpha xn$ ($x=1,2$) channels.

Conclusion: Comparative analysis of the residual cross-sections demonstrates the dominance of compound nuclear process in the energy range considered. The measured cumulative production cross-section of ${}^{97}\mathrm{Ru}$ is maximum, $\sim 850$ mb, at 66.6 MeV. The detailed analysis presented in this article would help to optimize the production parameters for ${}^{97}\mathrm{Ru}$ and also to understand the reliability of the theoretical models.

Figure 1

A $\gamma$-ray spectrum of 73.7 MeV ${}^{12}\mathrm{C}$ activated ${}^{89}\mathrm{Y}$ collected after 38 min of the EOB.

Figure 2

Comparison of experimental cross-sections of (a) ${}^{98}\mathrm{Rh}$, (b) ${}^{97m+g}\mathrm{Rh}$, (c) ${}^{96}\mathrm{Rh}$, and (d) ${}^{98+97(m+g)+96}\mathrm{Rh}$ from the ${}^{12}\mathrm{C}+{}^{89}\mathrm{Y}$ reaction with the theoretical estimations.

Figure 3

Variation of ICR of ${}^{97}\mathrm{Rh}$ at different bombarding energies.

Figure 4

Simplified decay scheme of ${}^{97g}\mathrm{Rh}$ and ${}^{97m}\mathrm{Rh}$ into ${}^{97}\mathrm{Ru}$.

Figure 5

Comparison of cumulative (${}^{97m+g}\mathrm{Rh}+{}^{97}\mathrm{Ru}$) and independent cross-sections of ${}^{97}\mathrm{Ru}$ from ${}^{12}\mathrm{C}+{}^{89}\mathrm{Y}$ reaction with the EMPIRE3.2.2 estimations.

Figure 6

Comparison of experimental excitation functions of (a) ${}^{96}\mathrm{Tc}$, (b) ${}^{95}\mathrm{Tc}$, (c) ${}^{94}\mathrm{Tc}$, and (d) ${}^{93}\mathrm{Tc}$ with the theoretical estimations.

Figure 7

(a) Same as described in the caption of Fig. 6 for ${}^{96+95+94+93}\mathrm{Tc}$. (b) Comparison of experimental excitation functions of ${}^{93m}\mathrm{Mo}$ with EMPIRE3.2.2.

Figure 8

Variation of PEQ fraction for $3n$ and $\alpha n+\alpha 2n$ channels.