III-3. Radiochemistry & Nuclear Chemistry

RIKEN Accel. Prog. Rep. 55 (2022)

RIKEN Accel. Prog. Rep. 55 (2022)

Production cross-sections of 52m Mn in alpha-particle-induced reactionsin natural vanadium
G. Damdinsuren,∗1,∗2 M. Aikawa,∗1,∗2,∗3 Kh. Tegshjargal,∗4 N. Erdene,∗4 S. Ebata,∗5,∗2 and H. Haba∗2

∗1
∗2
∗3
∗4
∗5

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
Graduate School of Science and Engineering, Saitama University400natV(,x)52Mn

350
300
Cross section [mb]The ground state of the 52m Mn radioisotope has a halflife of T1/2 = 5.6 days and decays via electron capture(70.6%) and positron emission processes (29.4%, Eβ+ = 242 keV). 52m Mn can be used in positron emission tomography (PET) imaging to study biological and physiological processes with a time scale similar to its decay.1) The routes for 52m Mn production include chargedparticle-induced reactions. Among the possible reactions, we focused on the α-particle-induced reaction onnatural vanadium targets. Eleven previous experimental studies were found in the EXFOR library.2) However,their data exhibited show large uncertainties and discrepancies. Therefore, we measured the excitation function of the nat V(α, x)52m Mn reaction. The experimental
result was compared with the literature data obtained
from the EXFOR database and TENDL-2019 data.3)
The stacked-foil activation technique and highresolution γ-ray spectrometry were used for cross-section
measurements. The experiment target consisted of puremetal foils of nat V (25-μm thick, 99% purity), nat Ti (5μm thick, 99.6% purity), and 27 Al (5-μm thick, 99.9%purity) from Nilaco Corp., Japan. 27 Al foils were inserted to sandwich nat V foils to separate the recoiled reaction products from nat V and nat Ti foils. nat Ti foils
were used in the nat Ti(α, x)51 Cr monitor reaction to assess beam parameters and energy loss in the particles inthe stack.
The target thickness was derived using the measured size and weight of the foils. The derived thickness of nat V, nat Ti, and 27 Al foils was 20.4, 2.24, and1.22 mg/cm2 , respectively. These foils were then cut
into 8 × 8 mm pieces to ﬁt a target holder that served
as a Faraday cup. Eleven sets of V-Al-Ti-Ti-Al foils werestacked into the target holder.
The stacked target was irradiated with a 50.6 ±0.2 MeV alpha-particle beam for 30 min. The primaryenergy was measured by the time-of-ﬂight method.4) Energy degradation in the stacked target was calculated using the SRIM code.5) The average beam intensity measured by the Faraday cup was 194 nA.
The γ-ray spectra of each irradiated foil were measured
by a high-resolution HPGe detector (ORTEC GEM25185-P) and analyzed using dedicated software (SEIKO
EG&G Gamma Studio). Each nat V foil was measured
with the following 27 Al catcher foil for the recoiled products. The distance between the detector and foils was


250
200
150
100
50This work
Bowman (1969)
Dmitriev (1969)
Michel (1982)
Rama (1987)
Levkovski (1991)
Singh (1993)
Sonzogni (1993)
Ismail (1993)
Singh (1995)
Chowdhury (1995)
Bindu (1998)
TENDL-2019010152025 3035404550

Energy [MeV]Fig. 1. Excitation function of the nat V(α, x)52m Mn reaction.

arranged to ensure a dead time of less than 3%.
The cross-sections of the nat Ti(α, x)51 Cr monitor reaction were derived to assess the beam parameters andtarget thickness. The γ line at 320.08 keV (Iγ = 9.91%)
from the decay of 51 Cr (T1/2 = 27.7025 d) in each
low-energy foil of Ti-Ti pairs were measured. The derived cross-sections were compared with the IAEA recommended values.6) Our result was consistent with therecommended values and no corrections were adopted fordata analysis.
Further, the cumulative cross-sections of the nat V(α,52mMn reaction were derived.
The shorter-livedx)
metastable state of the 52m Mn (T1/2 = 21.1 min) radionuclide decayed to the ground state 52m Mn (T1/2 =5.591 d) and 52 Cr (stable) soon after the end of thebombardment. The γ line at 935.544 keV (Iγ = 94.5%)
from the decay of 52m Mn was measured after cooling for
17 days. The cumulative cross-sections were obtained
from the net count of the γ line. Figure 1 shows thederived cross-sections in comparison to previous experimental studies and TENDL-2019 data.3) The present
cross-section data exhibited a smooth curve and they
were consistent with a part of previous experimental
data. The peak position and amplitude of TENDL-2019
data were diﬀerent from the experimental data.
G. Damdinsuren was granted a scholarship by the MJEED project (Mongolian-Japan Engineering Education
Development Program, J11B16).
References
1) F. Bianchi et al., Appl. Radiat. Isot. 166 (2020).
2) N. Otuka et al., Nucl. Data Sheets 120, 272 (2014).
3) A. J. Koning et al., Nucl. Data Sheets 155, 1 (2019).
4) T. Watanabe et al., Proc. 5th Int. Part. Accel. Conf.
(2014), p. 3566.
5) J. F. Ziegler et al., Nucl. Instrum. Methods Phys. Res. B
268, 1818 (2010).
6) F. Tárkányi et al., IAEA-TECDOC-1211 (2007).

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