Speaker
Description
Isomer production is important in nuclear applications, such as radiation safety and radioactive waste management, and theoretical nuclear physics, such as level structure. Although the isomer production can be described by EBITEM [1] in PHITS [2], the number of reactions used as benchmarks is limited. Thus, further verification of the EBITEM’s performance is essential.
To confirm the availability of EBITEM, we selected the $^{\rm 44g,m}$Sc production cross sections and the isomeric ratios of $^{44}$Sc as benchmarks due to following reasons: 1) the decay from the parent ($^{44}$Ti, T$_{1/2}$ = 59.1 y) is minuscule, 2) the de-excitation from $^{\rm 44m}$Sc (T$_{1/2}$ = 58.61 h) to $^{\rm 44g}$Sc (T$_{1/2}$ = 4.042 h) is negligible, and 3) $^{\rm 44m}$Sc (E$_{\gamma}$ = 271.25 keV) has the unrelated $\gamma$-line to $^{\rm 44g}$Sc (E$_{\gamma}$ = 1157.02 keV).
We have been measuring the nuclide production cross sections of GeV-energy proton incidence on the targets with the atomic number 21 to 30 by an activation technique at J-PARC. For the measurement of $^{45}$Sc, $^{\rm nat}$V, $^{55}$Mn, $^{59}$Co, $^{\rm nat}$Ni, and $^{\rm nat}$Cu targets, we acquired both $^{\rm 44g,m}$Sc production cross sections. However, for the measurement of $^{\rm nat}$Ti, $^{\rm nat}$Cr, $^{\rm nat}$Fe, $^{\rm nat}$Zn targets, some of the objective cross sections have not been reported. Thus, the purpose of this study is to analyze the data measured at J-PARC to obtain the missing cross sections.
We successfully acquired the cross sections of interest (5 reactions and 13 data points). In this poster, we compared our present data with the results of previous studies and the combination of nuclear reaction model and EBITEM. We also discuss the proton energy dependence and target-Z dependence of an isomeric ratio of $^{44}$Sc.
References
[1] Ogawa T., Hashimoto S., Sato T., et al., Development of gamma de-excitation model for prediction of prompt gamma-rays and isomer production based on energy-dependent level structure treatment, Nucl. Instrum. Meth. B, 325, (2014), pp. 35-42.
[2] Sato T., Iwamoto Y., Hashimoto S., et al., Recent improvements of the particle and heavy ion transport code system – PHITS version 3.33, J. Nucl. Sci. Technol., 61(1), (2024), pp. 127-135.
