Ⅲ-3. Radiochemistry & Nuclear Chemistry

RIKEN Accel. Prog. Rep. 53

Excitation function measurement for zirconium-89 and niobium-90
production using alpha-induced reactions on yttrium-89†
T. Murata,∗1,∗2 M. Aikawa,∗1,∗2,∗3 M. Saito,∗1,∗2 H. Haba,∗2 Y. Komori,∗2 N. Ukon,∗4,∗2 S. Takács,∗5 andF. Ditrói∗5Zirconium-89 (T1/2 = 78.41 h) and niobium-90(T1/2 = 14.6 h) are expected to be used for immunoPET.1,2) From the viewpoint of radionuclide production,
the investigation of eﬀective production reactions is valuable. We focused on the α-induced reactions on themonoisotopic element 89 Y to produce the two radionuclides. Five experimental studies on these reactions3–5)
were found in a literature survey. However, signiﬁcantdiscrepancies exist among the experimental data. Therefore, we were motivated to investigate α-induced reactions on 89 Y. The cross sections of co-produced radionuclides other than 89 Zr and 90 Nb were also determined.
The experiment was performed at the RIKEN AVF cyclotron. The stacked foil activation technique and highresolution γ-ray spectrometry, which are well-establishedmethods, were adopted for the experiment. The target
was composed of pure metallic foils of 89 Y (99% purity,Goodfellow Co., Ltd., UK), nat Ti (99.6% purity, NilacoCorp., Japan), and 27 Al (> 99% purity, Nilaco Corp.,Japan). The sizes and weights of the foils were measured
to determine their average thicknesses, which were foundto be 24.2, 5.1, and 5.5 µm for Y, Ti, and Al, respectively.
The three foils were cut into a small size of 1 cm × 1 cm
to ﬁt a target holder, which also served as a Faraday cup.
The stacked target was irradiated with a 50.9 ± 0.1-MeV
M-beam for 1 h. The incident energy of the beam wasmeasured using the time-of-ﬂight method.6) The energy
degradation in the target was calculated using stopping
powers obtained from the Stopping and Range of Ionsin Matter (SRIM) code.7) The average beam intensity
was measured as 411 nA using the Faraday cup. The
irradiated stacks were dismantled for the oﬀ-line γ-ray
spectrometry using HPGe detectors. The dead time waskept under 10% by adjusting the distances between themeasured foil and HPGe detector. Reaction and decay
data for the γ-ray spectrometry were taken from NuDat2.7.8)
The beam parameters were veriﬁed using the27Al(α, x)22 Na and nat Ti(α, x)51 Cr monitor reactions
in comparison with the IAEA recommended values.9)
Based on the comparison, the beam intensity was decreased by 4% from the measured value. The corrected
intensity of 398 nA was adopted to derive cross sections.
The excitation function of the 89 Y(α, x)89g Zr reaction†∗1∗2∗3∗4∗5Condensed from the article in Nucl. Instrum. Methods Phys.
Res. B 458, 21 (2019)
Graduate School of Biomedical Science and Engineering,
Hokkaido University
RIKEN Nishina Center
Faculty of Science, Hokkaido University
Advanced Clinical Research Center, Fukushima Medical University
Institute for Nuclear Research, Hungarian Academy of Sciences

Fig. 1. Comparison of cumulative cross sections of the89Y(α, x)89g Zr reaction with previously reported data3–5)
and TENDL-2017 data.10)

was determined. The measurement of the 909.15-keV γrays (T1/2 = 78.41 h, Iγ = 99.04%) was performed aftera cooling time of 10 days, which was long enough forcomplete decay of the parent nuclei 89g, m Nb and 89m Zr.
The cumulative cross sections of 89g Zr were obtained andcompared with three previous studies3–5) and TENDL2017 data10) in Fig. 1. One of the three experimental
data sets3) agree with our result. However, the others4,5)
deviate from ours.
In addition to 89g Zr, the production cross sectionsof 90 Nb and other co-produced radionuclides were determined and compared with previous studies and theTENDL-2017 data. Our results are reasonably consistent with some of the previous studies.
This work was supported by JSPS KAKENHI Grant
Number 17K07004.
References

1) M. A. Deri et al., Nucl. Med. Biol. 40, 3 (2013).
2) V. Radchenko et al., Radiochim. Acta 102, 433 (2014).
3) V. N. Levkovski, Cross Sections of Medium Mass Nuclide
Activation (A = 40–100) by medium energy protons andalpha particles (E = 10–50 MeV) (Inter-Vesi, Moscow,USSR, 1991).
4) N. L. Singh et al., Phys. Scr. 61, 550 (2000).
5) M. Shahid et al., Nucl. Instrum. Methods Phys. Res. B
358, 160 (2015).
6) T. Watanabe et al., Proc. 5th Int. Part. Accel. Conf.
(IPAC2014), 3566 (2014).
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B 268, 1818 (2010).
8) National Nuclear Data Center, The NuDat 2.7 database,
http://www.nndc.bnl.gov/nudat2/ .
9) A. Hermanne et al., Nucl. Data Sheets 148, 338 (2018).
10) A. J. Koning et al., Nucl. Data Sheets 155, 1 (2019).

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