III-3. Radiochemistry & Nuclear Chemistry

RIKEN Accel. Prog. Rep. 54 (2021)

RIKEN Accel. Prog. Rep. 54 (2021)

Excitation functions of deuteron-induced reactions on 141 Pr for
medical radioisotope production
M. Aikawa,∗1,∗2 T. Maehashi,∗3 D. Ichinkhorloo,∗1,∗2 Y. Komori,∗2 and H. Haba∗2

∗1
∗2
∗3

Faculty of Science, Hokkaido University
RIKEN Nishina Center
School of Science, Hokkaido University

350
141300
Cross section (mb)

Investigation of the production of medical radioisotopes is indispensable for the development of imagingand therapy. Radioisotopes 140 Nd (T1/2 = 3.37 d) and142
Pr (T1/2 = 19.12 h) are expected for 140 Nd/140 Pr
generator in positron emission tomography (PET)1)
and the treatment for arteriovenous malformations,2)
respectively. Some charged-particle-induced reactions
can produce these two radioisotopes. Among them,
we focused on deuteron-induced reactions on monoisotopic element 141 Pr. In a literature survey, only two
experimental studies for these reactions were found3,4)
below 30 MeV and their experimental cross-section
data are scattered. Therefore, we performed an experiment to measure the production cross sections of140
Nd and 142 Pr to contribute to the development ofnuclear medicine.
The experiment was performed at the RIKEN AVF
cyclotron. The stacked-foil activation technique andhigh-resolution γ-ray spectrometry were adopted in theexperiment.
The stacked target consisted of pure metallic foils of141
Pr and nat Ti. The nat Ti foils were interleaved forthe nat Ti(d, x)48 V monitor reaction to assess the beam
parameters and target thicknesses. The 141 Pr (purity:99%, thickness: 100 µm, size: 25 × 25 mm2 ) and nat Ti(purity: 99.6%, thickness: 5 µm, size: 50 × 100 mm2 )foils were purchased from Nilaco Corp., Japan. The
surface area and weight of each foil were measured
and their thicknesses were determined to be 67.6 and2.3 mg/cm2 . The foils were cut into a small size of
8 × 8 mm2 to ﬁt a target folder. Nine sets of Pr-Ti-Ti
foils were stacked into the target folder that served asa Faraday cup.
The stacked target was irradiated with a deuteronbeam for 30 min. The beam intensity of 107 nA wasmeasured by the Faraday cup. The incident energyof 24.1 MeV was measured using the time-of-ﬂight
method. Energy degradation in the stacked target wascalculated using the srim code.5)
γ rays emitted from the irradiated foils were measured using an HPGe detector. The eﬃciency of thedetector was calibrated using a standard γ-ray point
source. Each 141 Pr foil with the next nat Ti catcher
foil for recoiled products was measured ﬁve times after cooling times from 2.2 h to 40.2 d. The dead time
was kept below 5.2%. The required nuclear data wereretrieved from the NuDat 2.8 online database.6)
The nat Ti(d, x)48 V monitor reaction was used to as-Pr(d,p)142PrLange 1968
Hermanne 2009TENDL-2019
This work

250
200
150
100
50005101520
Energy (MeV)

2530Fig. 1. Cross sections of the 141 Pr(d, p)142 Pr reaction incomparison with the previous data3,4) and the TENDL2019 values.8)

sess the beam parameters and target thicknesses. The
cross sections of the monitor reaction were derived
from the measurement of the 983.5-keV γ line. Theresult was compared with the IAEA recommended values.7) According to the comparison, the beam intensity
was corrected by −7%. The corrected intensity andmeasured thicknesses were used to deduce the production cross sections.
The cross sections of the 141 Pr(d, p)142 Pr reaction
were derived from the measurement of the 1575.6-keV
γ line (Iγ = 3.7%) with decay of 142 Pr. The resultis shown in Fig. 1 with the previous studies3,4) andthe TENDL-2019 values.8) The previous experimental
data and their trends are almost consistent with ourresult within the uncertainties, which are large due tothat of the γ-ray intensity (∆Iγ /Iγ = 10.8%). TheTENDL-2019 values were found to be smaller than all
experimental data.
References

1) K. P. Zhernosekov et al., Radiochim. Acta 95, 319 (2007).
2) S. W. Lee, W. D. Reece, Phys. Med. Biol. 50, 151(2005).
3) J. Lange et al., Radiochim. Acta 9, 66 (1968).
4) A. Hermanne et al., Nucl. Instrum. Methods Phys. Res.
B 267, 727 (2009).
5) J. F. Ziegler et al., srim: the Stopping and Range ofIons in Matter (2008).
6) National Nuclear Data Center, The NuDat 2.8database, http://www.nndc.bnl.gov/nudat2/ .
7) A. Hermanne et al., Nucl. Data Sheets 148, 338 (2017).
8) A. J. Koning et al., Nucl. Data Sheets 155, 1 (2019).

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