III-3. Radiochemistry & Nuclear Chemistry

RIKEN Accel. Prog. Rep. 55 (2022)

RIKEN Accel. Prog. Rep. 55 (2022)

Activation cross sections of deuteron-induced reactions on natural
chromium up to 24 MeV
H. Huang,∗1,∗2 M. Aikawa,∗1,∗2,∗3 Y. Hanada,∗1,∗2 and H. Haba∗252g

∗1
∗2
∗3

Graduate School of Biomedical Science and Engineering,
Hokkaido University
RIKEN Nishina Center
Faculty of Science, Hokkaido University- 155 -250
Cross section (mb)

Mn (T1/2 = 5.591 d) that decays by electron capture and positron emission can be used in positronemission tomography (PET).1) 51 Cr (T1/2 = 27.8 d)that decays by the same mode was used to label red
blood cells as a tracer in the measurement of the mass
and volume of living systems.2) These medical radionuclides can be produced via charged-particle-induced
reactions on neighbor elements. We focused on the
deuteron-induced reaction on natural chromium. Experimental literature data regarding the cross sectionsof the reaction are inconsistent,3–5) and therefore, weperformed the experiment to measure the production
cross sections of 52g Mn and 51 Cr. In addition, the crosssections of the by-products 48 V and 52m, 54 Mn were determined.
We adopted the well-established stacked-foil activation technique followed by high-resolution gamma-ray
spectrometry to determine excitation functions. The
target comprised nickel-chromium (NiCr) alloy (99.9%purity, Goodfellow Co., Ltd., UK), nat Ti (99.6% purity, Nilaco Corp., Japan), and 27 Al (>99% purity,Nilaco Corp., Japan) foils. The nat Ti foil was used
for the nat Ti(d, x)48 V monitor reaction to assess thebeam parameters. The 27 Al foil was interleaved to collect recoiled products. The average thickness of eachfoil was derived from their measured weight and size.
We analyzed the elemental ratio of the NiCr alloy foil
by a scanning electron microscope with an energy dispersive X-ray spectrometer (Hitachi TM4000 Plus II).
The measured mass ratios were Cr 21.5%, Ni 76.7%,
and Mn 1.7%, respectively. All foils were then cut into
squares of 8 × 8 mm2 to ﬁt the size of a target holderthat served as a Faraday cup. Thirteen sets of NiCrNiCr-Al-Ti-Ti-Al foils were stacked as the target.
The stacked target was irradiated for 15 min by a24-MeV deuteron beam from the AVF cyclotron atRIKEN. The average intensity and primary energyof the beam were measured to be 105 nA and 24.0
± 0.1 MeV. Energy degradation in the stacked target was calculated using stopping powers obtained by
the SRIM code.6) Gamma-ray spectrometry was performed using a high-purity germanium detector (ORTEC GEM30P4-70) and analyzed by the analysis software (SEIKO EG&G Gamma Studio). Only gammaspectra from each second NiCr alloy and Ti foil weremeasured assuming that recoiled nuclides from the second foils were compensated by those from the ﬁrst.

Hermanne(2011)
Simeckova(2018)
Bianchi(2020)
TENDL-2019
This work200150
1005000510152025

Energy (MeV)
Fig. 1. Cross sections of the nat Cr(d, x)52g Mn reaction withprevious data3–5) and the TENDL-2019 values.8)

During 1 h–32 d cooling, NiCr alloy foils were measured 7 times to assess the radionuclides with diﬀerent
half-lives. The measurement distances were 3–50 cm.
The dead time was kept below 5.2%.
The cross sections of the nat Ti(d, x)48 V monitor reaction were derived and compared with the recommended values of IAEA.7) The comparison results indicated that, the beam intensity was corrected by −1.1%
within the uncertainty (5%). The other parameters
were adopted without any correction.
We derived the cross sections using the measurementof the 935.544-keV gamma line (Iγ = 94.5%) emittedwith the decay of 52g Mn. A short-lived metastable isomer 52m Mn (T1/2 = 21.1 min) decayed to the groundstate 52g Mn by isomeric transition with a branchingratio of 1.78%. Thus, we determined the cumulative
cross section of 52g Mn. We compare our data with theprevious studies3–5) and the TENDL-2019 values8) inFig. 1; our data are less scattered and in agreementwith the recently published data.4,5) The theoreticalvalues of TENDL-2019 obviously overestimate the experimental data.
References
1) I. F. Chaple et al., J. Nucl. Med. 59, 1655 (2018).
2) S. J. Gray et al., J. Clin. Investig. 29, 1604 (1950).
3) A. Hermanne et al., Nucl. Instrum. Methods Phys. Res.
B 269, 2563 (2011).
4) E. Šimečková et al., Phys. Rev. C 3, 034606 (2018).
5) F. Bianchi et al., Appl. Radiat. Isot. 166, 109329 (2020).
6) J. F. Ziegler et al., SRIM: the Stopping and Range ofIons in Matter (2008), http://www.srim.org/ .
7) F. Tárkányi et al., IAEA-TECDOC-1211 (2007).
8) A. J. Koning et al., Nucl. Data Sheets 113, 2841 (2012).

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