III-3. Radiochemistry & Nuclear Chemistry

RIKEN Accel. Prog. Rep. 54 (2021)

RIKEN Accel. Prog. Rep. 54 (2021)

Production cross sections of 155 Tb in deuteron-induced reactions
on natural gadolinium
D. Ichinkhorloo,∗1,∗2 M. Aikawa,∗1,∗3,∗4 Ts. Zolbadral,∗2,∗3,∗4 Y. Komori,∗3 and H. Haba∗3
Terbium-155 (T1/2 = 5.32 d) can be used for singlephoton emission computed tomography (SPECT)1) andproduced through charged-particle-induced reactions.
Among the reactions, we focused on the deuteroninduced reaction on natural gadolinium. In a literature survey, three experimental studies on the reaction
were found.2–4) However, some discrepancies could befound among the experimental data. Therefore, we measured the cross sections of the deuteron-induced reaction
on natural gadolinium. The result was compared withthe previously published experimental data2–4) and theTENDL-2019 data.5)
The experiment was performed at the RIKEN AVF
cyclotron. We used the stacked-foil activation techniqueand the high-resolution γ-ray spectrometry to determine
the activation cross sections.
The stacked target consisted of 8×8 mm2 foils cut froma large nat Gd foil (25 µm, 50×100 mm2 , 99.9% purity, Nilaco Corp., Japan) and a nat Ti foil (5 µm, 50 × 100 mm2 ,99.6% purity, Nilaco Corp., Japan). The isotopic composition of nat Gd is 152 Gd (0.2%), 154 Gd (2.2%), 155 Gd(14.8%), 156 Gd (20.5%), 157 Gd (15.7%), 158 Gd (24.8%)
and 160 Gd (21.8%).
The sizes and weights of the large foils were measured
to derive the thicknesses. The thicknesses of the nat Gd
and nat Ti foils were found to be 25.3 and 2.34 mg/cm2 ,respectively. The nat Ti foils were interleaved for thenatTi(d, x)48 V monitor reaction to assess beam parameters and target thicknesses. The cut foils were stacked
into a target holder, which served as a Faraday cup.
The stacked target was irradiated with the beam for
60 min. An average intensity of 98.1 nA was measured
by the Faraday cup. The beam energy was measured by
the time-of-ﬂight method.6) Energy degradation in thestacked target was calculated using the Stopping andRange of Ions in Matter (srim) code.7)
The γ-rays emitted from each irradiated foil weremeasured using a high-resolution high-purity germanium (HPGe) detector and analyzed using the software
Gamma Studio software (SEIKO EG&G).
The total uncertainties (∼10%) were estimated fromthe square root of the quadratic summation of each component; statistical uncertainty (0.4–1.5%), target thickness (2%), target purity (1%), beam intensity (5%), detector eﬃciency (6%) and γ-ray intensity (1.3%).
The cross sections of the nat Ti(d, x)48 V monitor reaction were derived using the line at 983.525 keV (Iγ =99.98%). The derived cross sections were compared with∗1
∗2
∗3
∗4

Faculty of Science, Hokkaido University
Nuclear Research Center, National University of Mongolia
Nishina Center for Accelerator-Based Science, RIKEN
Graduate School of Biomedical Science and Engineering,
Hokkaido UniversityFig. 1. Excitation function of the nat Gd(d, x)155 Tb reaction along with the previously published data2–4) andTENDL-2019 data.5)

the values recommended by the International Atomic
Energy Agency (IAEA).8) We could obtain good agreements between the results and the recommended values.
The γ line at 105.3 keV (Iγ = 25.1%) emitted with the155Tb decay was measured to derive the cross sections ofthe nat Gd(d, x)155 Tb reaction. The measurements wereperformed after a cooling time of 3 days. The result ispresented in Fig. 1 along with the previously publishedexperimental data2–4) and TENDL-2019 data.5) Our result shows good agreement with the previous experimental data within the uncertainty, except for one data pointat 22 MeV of Tárkányi et al.4) The TENDL-2019 data
substantially overestimate all the experimental data inthe lower energy region.
In the summary, we performed an experiment to measure the excitation functions of the nat Gd(d, x)155 Tb reaction up to 24.1 MeV at the RIKEN AVF cyclotron.
The production cross sections of 155 Tb were determined.
The result was compared with the experimental data
studied published previously and the TENDL data. We
good agreement between our result and the previous experimental results.
References

1) C. Müller et al., J. Nucl. Med. 53, 1951 (2012).
2) C. Duchemin et al., Appl. Radiat. Isot. 118, 281 (2016).
3) F. Szelecsényi et al., J. Radioanal. Nucl. Chem. 307, 1877(2016).
4) F. Tárkányi et al., Appl. Radiat. Isot. 83, 25 (2014).
5) A. J. Koning et al., Nucl. Data Sheets 155, 1 (2019).
6) T. Watanabe et al., Proc. 5th Int. Part. Accel. Conf.
(IPAC 2014), 3566 (2014).
7) J. F. Ziegler et al., srim: the Stopping and Range of Ionsin Matter, http://www.srim.org .
8) A. Hermanne et al., Nucl. Data Sheets. 148, 338 (2018).

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