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Chemical studies of transactinide elements (atomic number Z ≥ 104) are of great importance to understand the relativistic effects; however, the experimental methodology is limited owing to the single atom situation and short lifetimes of the heavy atoms. Herein, we report the successful establishment of a new solvent extraction method for transactinide elements using a flow-type solvent extraction apparatus. The developed apparatus has a reaction unit in which PTFE chips are packed to shorten the time required for the transfer of metal complexes between the aqueous and organic phases. Equilibrium distribution ratios were obtained for Zr and Hf: the homologues of element 104, rutherfordium (Rf), in a short time considering the half-life of 261Rf as 68 s. In addition, the developed extraction apparatus was connected to an online transportation system for the nuclear reaction products at an accelerator, and online solvent extraction experiments were conducted with the short-lived nuclear reaction products of 89m,gZr and 173Hf. Distribution ratios consistent with the equilibrium ratios were successfully acquired. The solvent extraction system for experiments on Rf was thus established, and the optimal experimental conditions were determined. [ABSTRACT FROM AUTHOR]

Solid-liquid extraction of the group 4 elements Zr and Hf, which are homologues of Rf ( Z = 104), and Th, a pseudo homologue, by triisooctylamine (TIOA) from HCl solutions was performed by batch method. After examining the time required to reach extraction equilibrium for these elements in various concentrations of TIOA and HCl, we investigated in detail variations in the distribution coefficients ( Kd) with TIOA and HCl concentrations. The Kd values of Zr and Hf increased with increasing the HCl and TIOA concentrations, suggesting an increase in the abundance of the anionic chloride complexes of Zr and Hf. On the other hand, the Kd values of Th were low in all the HCl concentrations studied, implying that Th does not form anionic species dominantly. We developed a new automated batch-type solid-liquid extraction apparatus for repetitive experiments on transactinide elements. Using this apparatus, we performed solid-liquid extraction employing the radioactive nuclides 89mZr and 175Hf produced by nuclear reactions and transported continuously from the nuclear reaction chamber by the He/KCl gas-jet system. It was found that the distribution behaviors in 7-11 M HCl are almost constant in the time range 10-120 s, and the Kd values are consistent with those obtained in the above manual experiment. This result suggests that the chemical reactions in the extraction process reach equilibrium within 10 s for Zr and Hf under the present experimental conditions. It took about 35 s for the extraction using the apparatus. These results indicate the applicability of the present extraction using the developed apparatus to 261Rf ( T1/2 = 68 s) experiments. [ABSTRACT FROM AUTHOR]

• Deuteron-induced nuclear reactions on natural erbium were studied. • Stacked-foil activation technique and γ-ray spectroscopy was used. • Production parameters of 167mTm in NCA form is optimized. • Measured (d,p) data is important to improve the predicting capability of model codes. Excitation functions for the natEr(d, x)163,165,166,167,168,170Tm and natEr(d, x)171Er nuclear reactions were measured from the respective thresholds up to 24 MeV by using a stacked-foil activation technique combined with HPGe γ-ray spectrometry. Measured data show a partial agreement when compared with the available literature data, theoretical data extracted from the TENDL-2019 library, and predicted data by the model code EMPIRE-3.2.2. Estimated physical thick target yields of the reaction products show close values to the directly measured ones available in the literature. The deduced yield curves indicate that a typical irradiation (E d = 15 MeV, I d = 100 µA, t irr = 72 h) of enriched 167Er target by a low energy deuteron cyclotron is suitable to obtain more than a hundred GBq activity of 167Tm with negligible impurity from 168Tm. Measured data of 170Er(d,p)171Er reaction have great significance to improve the predicting capability of the model code. [ABSTRACT FROM AUTHOR]

• We conducted an experiment to measure activation cross sections of alpha-particle-induced reactions on natural tungsten. • The stacked-foil activation technique and high-resolution gamma-ray spectrometry were used for the measurement. • Production cross sections of 185,183m,183g,182gOs and 188g,186g,184g,183g,182g,181Re were determined up to 50 MeV. • The results were compared with the previous experimental data and the TENDL-2019 values. We measured activation cross sections of alpha-particle-induced reactions on natural tungsten targets. The stacked-foil activation technique and gamma-ray spectrometry were used. Production cross sections of 185,183m,183g,182gOs and 188g,186g,184g,183g,182g,181Re were determined. The results were compared with experimental literature data and the TENDL-2019 and TENDL-2021 values. The cross sections of the most reactions were determined for the first time. [ABSTRACT FROM AUTHOR]

• The excitation functions of deuteron-induced reactions on 89Y up to 24 MeV were measured. • Production cross sections of some Zr, Y and Sr radioisotopes were measured. • Physical yield of 89Zr was deduced from the measured cross sections. Activation cross sections of the deuteron-induced reactions on 89Y were measured up to 24 MeV deuteron energy. The experiment was performed at the RIKEN AVF cyclotron. Excitation functions of the reactions 89Y(d,x)88,89Zr, 88,90mY, 87mSr were obtained by using the stacked-foil activation method and gamma-ray spectrometry. The results were compared with previous experimental data and the prediction of the TALYS nuclear reaction model code adopted from TENDL-2017 library. Physical thick target yield of 89Zr was derived from the measured cross sections. [ABSTRACT FROM AUTHOR]

As an alternative production route for the medically interesting 178mTa isotope production cross sections of alpha particle induced nuclear reaction of the natHf(α,x)178W–178mTa process was investigated. Activation method, stacked target technique, and high resolution off-line γ-ray spectrometry were applied. Excitation functions of the natHf(α,x)178W reaction and of several other side reactions were determined up to 51 MeV. Activation cross section data were determined for the following reactions: natHf(α,x)176,177,178W, natHf(α,x)175,176,177,178g,180g,182g,183Ta, and natHf(α,x)173,175,179m2,180m,181Hf. The measured experimental data were compared with the results of earlier experimental data and the results of TALYS nuclear reaction model code calculation tabulated in the TENDL-2017 data library. Experimental data are presented for the first time in the 40–50 MeV energy region. Thick target yields were calculated for elemental hafnium target using the fitted experimental cross section data. [ABSTRACT FROM AUTHOR]

Activation cross sections of α-particle induced reactions on natYb were measured. The stacked foil technique, the activation method and the γ-ray spectrometry were used. The stacked target consisted of natYb and natTi foils was irradiated with a 51.0-MeV α beam at the RIKEN AVF cyclotron. The γ rays emitted from the irradiated foils were measured using a high-resolution HPGe detector. Production cross sections of 170,171,172,173,175Hf, 171,172,173,177gLu and 169Yb were determined. The results were compared with previous experimental studies and theoretical calculations. For most of the reactions a consistent agreement was found. [ABSTRACT FROM AUTHOR]

The excitation functions were measured for the nat Cu(α,x) 66,67 Ga, 65 Zn, 57,58,60 Co reactions in the energy range of 16.5 −50 MeV. A conventional stacked-foil activation technique combined with HPGe γ-ray spectrometry was employed to determine cross-sections. The measured cross-sections were critically compared with relevant previous experimental data and also with the evaluated data in the TENDL-2014 library. Present results confirmed some of the previous experimental data, whereas only a partial agreement was found with the evaluated data. The measured data are useful for reducing the existing discrepancies in the literature, to improve the nuclear reaction model codes, and to enrich the experimental database towards various applications. [ABSTRACT FROM AUTHOR]

Production cross sections of 153,145Sm via alpha-particle-induced reactions on natNd were measured up to 23 MeV. The stacked-foil activation technique and high-resolution gamma-ray spectrometry were adopted for the measurement. The obtained cross sections were compared with the literature data and the TENDL-2019 and TENDL-2021 values. Physical thick target yields of the two radionuclides were derived from the measured cross sections. • The excitation functions of alpha-particle-induced reactions on natNd were measured. • The production cross sections of 153,145Sm were determined up to 23 MeV. • The results were compared with the literature data and the TENDL values. • Physical thick target yields were deduced using the measured cross sections. [ABSTRACT FROM AUTHOR]

Excitation functions of alpha-particle induced reactions on natNd up to 50 MeV were measured at the RIKEN AVF cyclotron. To derive cross sections activation method, stacked target technique and gamma-ray spectrometry were adopted. Formations of 153,145Sm, 151,150,149,148m,148g,144,143Pm, and 149,147Nd were investigated. The results were compared with the previous experimental data and the TENDL-2019 data. Discrepancies among most of them were found. • The excitation functions of alpha-particle-induced reactions on natNd up to 50 MeV were measured. • The production cross sections of Nd, Pm and Sm radioisotopes were determined. • The results were compared with the previous experimental data and the TENDL data. [ABSTRACT FROM AUTHOR]

Activation cross sections of alpha-induced reactions on natural erbium were measured using a 50.9-MeV alpha-beam at the RIKEN AVF cyclotron. Well-established methods for the measurements, the stacked-foil activation technique and gamma-ray spectrometry, were used. Production cross sections of 166,169Yb and 165,166,167,168,170,173Tm were determined. This is the first measurement of the cross sections of 166,170Tm. The integral yield of the medical radionuclide 169Yb was derived from the measured excitation function. • Excitation functions of alpha-induced reactions on natEr up to 51 MeV were measured. • Production cross sections of Yb and Tm radioisotopes were determined. • End-of-bombardment activity of 169Yb was deduced. [ABSTRACT FROM AUTHOR]