Ⅲ-3. Radiochemistry & Nuclear Chemistry

RIKEN Accel. Prog. Rep. 53

Production cross sections of 68 Ga via deuteron-induced reactions onnatural zinc
Ts. Zolbadral,∗1,∗2 M. Aikawa,∗1,∗3,∗2 D. Ichinkhorloo,∗3,∗2 Kh. Tegshjargal,∗4 N. Javkhlantugs,∗4 Y. Komori,∗2and H. Haba∗2
Ga (T1/2 = 68 min), a positron emitter, is a valuable medical isotope used for positron emission tomography (PET). One of the production routes of this radionuclide is the deuteron-induced reaction on zinc. Ina literature survey, only two datasets of the experimental cross sections of the nat Zn(d, x)68 Ga reaction werefound,1,2) and these data show a remarkable discrepancy. It is necessary to obtain reliable cross sections toinvestigate the best production route for practical use.
Therefore, we measured the production cross sectionsof 68 Ga via the deuteron-induced reaction on naturalzinc.
The stacked-foil activation method and γ-ray spectrometry were used. The stacked target was composedof metallic foils of nat Zn (17.64 mg/cm2 , 99.9% purity) and nat Ti (9.13 mg/cm2 , 99.6% purity). The target was irradiated for 22 min by a 24-MeV deuteronbeam from the RIKEN AVF cyclotron. The incident beam energy was measured using the time-ofﬂight method. The energy degradation in the stacked
foils was calculated using SRIM code.3) The beam intensity was measured using a Faraday cup and crosschecked using the nat Ti(d, x)48 V monitor reaction.4)
By referring to the cross sections of the monitor reaction, the beam intensity was increased 6.6% from themeasured value and thereby corrected to 102.4 nA.
The γ-ray spectra of the irradiated foils were measured using a high-resolution HPGe detector (ORTEC68Fig. 2. Integral yield of 68 Ga.

GMX30P4-70) without chemical separation. The detector was calibrated using a standard mixed multiple
γ-ray-emitting point source. The distance between thedetector and foils was chosen to keep the dead time lessthan 7%.
The cross sections of the nat Zn(d, x)68 Ga reaction
were derived from the measurements of the 1077.34keV γ-line (Iγ = 3.22%) associated with the 68 Ga decay. The excitation function of the reaction is shownin Fig. 1 in comparison with previous data1,2) and thetheoretical estimation of TENDL-2017.5) Our result is
consistent with the data reported by Šimečková et al.2)
but inconsistent with those reported by Nassiﬀ andMünzel1) in the whole investigated energy region. The
TENDL-2017 data overestimate the experimental dataaround the peak in the energy range of 8–18 MeV.
The physical yield of 68 Ga was deduced from themeasured cross sections. The derived yield is shown inFig. 2. The physical yield of 68 Ga via the deuteroninduced reaction on zinc is reported for the ﬁrst time.
This work is supported by JSPS KAKENHI Grant
Number 17 K07004. Ts.Z. was granted a scholarshipby the M-JEED project (Mongolian-Japan Engineering Education Development Program, J11B16).
References

Fig. 1. Excitation function of the nat Zn(d, x)68 Ga reaction.
∗1
∗2
∗3
∗4

Graduate School of Biomedical Science and Engineering,
Hokkaido University
RIKEN Nishina Center
Faculty of Science, Hokkaido University
School of Engineering and Applied Sciences, National University of Mongolia- 190 -1) S. J. Nassiﬀ, H. Münzel, Radiochem. Radioanal. Lett.
12, 353 (1972).
2) E. Šimečková et al., EPJ Web Conf. 146, 11034 (2017).
3) J. F. Ziegler et al., Nucl. Instrum. Methods Phys. Res.
B 268, 1818 (2010).
4) A. Hermanne et al., Nucl. Data Sheets 148, 338 (2018).
5) A. J. Koning et al., Nucl. Data Sheets 155, 1 (2019).