Ⅲ-3. Radiochemistry & Nuclear Chemistry

RIKEN Accel. Prog. Rep. 50 (2017)

Production cross sections of 169 Yb in deuteron-induced reactions on169Tm∗1,∗2∗1,∗2∗2M.
M.
Y.
H.
M. Saito,Saito,∗1,∗2
M. Aikawa,
Aikawa,∗1,∗2
Y. Komori,
Komori,∗2H. Haba,
Haba∗2 and S. Takács∗3

∗1
∗2
∗3

Graduate School of Science, Hokkaido University
RIKEN Nishina Center
MTA ATOMKI, Hungarian Academy of Sciences- 259 -169

800Tm(d,2n)

169This work
Tarkanyi et al. 2007
Hermanne et al. 2009TENDL2015

Yb

700
Cross section (mb)Radioactive isotopes (RI) are used in many application ﬁelds such as engineering and medicine. The
medical RI 169 Yb (T1/2 = 32.018 d, EC = 100%) is anAuger electron and X-ray emitter suitable for use inbrachytherapy.1,2) The proton-,3–5) deuteron-,6–8) and
α-induced reactions9) on a monoisotopic 169 Tm target
were investigated by several research groups. Basedon the experimental cross-section data, the deuteroninduced reaction on 169 Tm is one of the best candidates for the production of 169 Yb owing to the large
6–8)
cross section of the (d,2n) reaction.
reaction6–8). However, theexperimental cross-section data for the 169 Yb production by deuteron-induced reactions show relatively
large uncertainties and scattering; therefore, the excitation function has not been deﬁned properly yet.
In this paper, we report cross-section data of the169Tm(d,2n)169 Yb reaction using thin metallic thulium
foils to reduce the uncertainty of the experimental
data.
The excitation function of the deuteron-induced reactions on 169 Tm were measured by the stacked-foil
activation method using high-resolution γ-ray spectroscopy to assess the activity of the irradiated target foils. 169 Tm metallic foils (purity: 99%, Goodfellow Co., Ltd., UK) were stacked with nat Ti (purity:99.9%, Goodfellow Co., Ltd., UK) and 27 Al foils (purity: >99.95%, Nilaco Corp., Japan) for monitoring
the beam parameters and for degrading the beam energy. The average thicknesses of Tm, Ti, and Al foils
were determined by measuring the surface area andweight of a larger piece of each foil and found to be
28.65, 4.95, and 13.44 mg/cm2 , respectively. The irradiation was performed at the AVF cyclotron of theRIKEN RI Beam Factory. The target was irradiatedin a Faraday-cup with a deuteron beam of 24.36 MeV
and an average beam intensity of 135.6 nA for 75 min.
The beam intensity was increased by 6.4% in agreement with the nat Ti(d,x)48 V monitor reaction. The
incident beam energy was measured by the time-ofﬂight method using plastic scintillator monitors.10)
Nuclear decay data of 169 Yb are taken from theonline NuDat 2.6 database.11) The energy-dependent
cross sections of the 169 Tm(d,2n)169 Yb reaction werederived from the γ-line at 177.21 keV (22.28%). Results are shown in Fig. 1 together with the previously
measured experimental data6–8) and the extracted result of the TALYS calculation (TENDL-201512) ). The
lowest measured cross section was 0.20 mb at 5.1 MeV

600500400300200
1000051015202530

Energy (MeV)

Fig. 1. The excitation function of the 169 Tm(d,2n)169 Ybreaction is shown with a spline ﬁt over our experimental
data. The result is compared with the previous experi12)
TENDL-201512).
mental data6–8) and TENDL-2015.

while the highest measured cross section was 682.8 mb
at 13.5 MeV. This peak energy is in good agreementwith the previous data,6–8) although the present crosssections are slightly higher.
In summary, we have measured the cross sectionsof the deuteron-induced reactions on 169 Tm to produce 169 Yb by using the stacked foil activation method.
Thin metallic Tm foils were irradiated by a 24.36-MeV
deuteron beam, and the activity of the produced radioisotopes was determined by high-resolution γ-ray
spectrometry. The obtained excitation functions werecompared with the earlier experimental data,6–8) andgood agreements were found in general.
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