Ⅱ-3. Nuclear Data

RIKEN Accel. Prog. Rep. 49 (2016)

Cross section measurement of residues in proton- anddeuteron-induced spallation reactions of 93 Zr and 93 Nb
S. Kawase,∗1 Y. Watanabe,∗1 K. Nakano,∗1 T. Kin,∗1 S. Araki,∗1 H. Wang,∗2 H. Otsu,∗2 H. Sakurai,∗2S. Takeuchi,∗3 Y. Togano,∗3 T. Nakamura,∗3 Y. Maeda∗4 for ImPACT-RIBF collaboration
The long-lived ﬁssion products (LLFPs), which areproduced in nuclear reactors have been an important
issue because of the diﬃculty of their disposal owing
to their remarkably long lifetimes. Therefore, a treatment method to transform the LLFPs into short-lived
and/or low-toxic materials is strongly desired, and nuclear transmutation technology is one of the promising candidates for this. However, the reaction data of
LLFPs required for the design of optimum pathways ofthe transmutation process are currently quite scarce.
We performed an experiment to measure isotopic
production cross section of 93 Zr, which is an LLFP
nuclide with a half-life of 1.61 × 106 years, using
proton- and deuteron-induced spallation reactions atthe RIKEN RI Beam Factory (RIBF). For the experimental setup, see Ref.1)
Figure 1 shows one of the plots, which was used forparticle identiﬁcation using the ZeroDegree spectrometer (ZDS). Each reaction residue was successfully identiﬁed with a 10σ separation of mass number A. The
isotopic production cross section was obtained fromthe production yield for each nuclide and the number ofbeam particles. The transmission ratio in the ZDS wasestimated from the position distribution at a dispersive
focal plane F9. Then the cross sections were comparedwith the calculations using PHITS2) with the IntraNuclear Cascade model of Liège (INCL)3) and the Generalized Evaporation Model (GEM)4) . Figure 2 shows
the preliminary results for Nb, Zr, Sr, and Kr isotopes
corresponding to proton- and deuteron-injection. The
calculations reproduced the experimental cross section
to some extent, but they underestimate the numberof evaporated neutrons and hence the resulting crosssections are distributed in an A region slightly larger
than the experimental ones. Further examination ofthe calculation models is needed.
The analysis for the spallation reaction on 93 Nb,
which was included in the 93 Zr beam setting, is underway. The cross sections of 93 Nb will be comparedwith the experimental data obtained using the activation method5) in order to verify the eﬀectiveness of themethod used in this experimental series.
This work was funded by the ImPACT Program ofthe Council for Science, Technology and Innovation(Cabinet Oﬃce, Government of Japan).
∗1
∗2
∗3
∗4

proton number Z

93

Zr (100 MeV/u) w/ CH target
24293

Zr

102

40
38
36

1034
32
30

128
26
2.1

2.15

2.2

2.25

2.3

2.35

Mass-to-charge ratio A/Q

Fig. 1. Correlation of proton number Z and mass-to-charge
ratio A/Q of reaction residues produced from 93 Zr beamat 100 MeV/u and CH2 target.

Fig. 2. Experimental and calculated cross sections for spallation reactions of 93 Zr at 100 MeV/u with protons anddeuterons.

References
1) H. Wang et al., In this report.
2) T. Sato et al., J. Nucl. Sci. Technol., 50, 913 (2013).
3) A. Boudard et al., Phys. Rev. C 87, 014606 (2013).
4) S. Furihata, Nucl. Instr. and Meth. B 171, 251 (2000).
5) Yu. E. Titarenko, Phys. Atom. Nucl. 74, 537 (2011).

Faculty of Engineering Sciences, Kyushu University
RIKEN Nishina Center
Graduate School of Science and Engineering, Tokyo Institute of Technology
Department of Applied Physics, University of Miyazaki- 87 -