Research Activities 1991–2016

RIKEN Accel. Prog. Rep. 50 (2017)

Research activities of Research Instruments GroupToshiyuki Kubo ∗1,∗2
The Research Instruments Group, consisting of theBigRIPS team, the SAMURAI team, the GARIS team(which presently belongs to the super-heavy element
group), the detector team, and the computing and network team (sometimes called data acquisition team),is the driving force for the continuous enhancementof activities and competitiveness of experimental research at RIBF. The group has been in charge of thedesign, development, construction, operation, and improvement of core research instruments at RIBF, suchas the BigRIPS separator,1,2) the ZeroDegree spectrometer,2) the SAMURAI spectrometer,3,4) and theSHARAQ spectrometer,5,6) and also those of their related infrastructure and equipment.7–11) Figures 1–3
show photographs of these research instruments.
Furthermore, the Research Instruments Group is incharge of the production of rare isotope (RI) beams
using the BigRIPS separator and routinely delivers RI
beams to every experiment performed at RIBF. The
superconducting in-ﬂight separator BigRIPS was commissioned in March 2007 and has been used to produce a variety of RI beams through the in-ﬂight ﬁssion of a 238 U beam as well as projectile fragmentationof various heavy-ion beams such as 18 O, 48 Ca, 70 Zn,
78
Kr, and 124 Xe beams. It was designed and built
as a new-generation separator, and it is characterized
by three major features: large ion-optical acceptances,
two-stage structure, and excellent performance in theparticle identiﬁcation of RI beams, which enabled veryeﬃcient production of RI beams. These advanced features of the BigRIPS separator, together with the capability and performance of the RIBF accelerators,
have allowed us to greatly expand the regions of accessible exotic nuclei, compared with old-generation inﬂight facilities.12) The scope of RI-beam experiments
has also been expanded, and studies of exotic nuclei at
RIBF have been promoted signiﬁcantly.
The research instruments group continuously performed R&D studies in order to improve the performance of the systems, which included ion-optics,13)
particle identiﬁcation,14) and beam-line detectors.15)
The group also conducted experimental studies, suchas systematic measurements of production crosssections 16) and search for new isotopes 17–19) and newisomers.20) A number of new isotopes and new isomers have been discovered using the BigRIPS separator. The production of RI beams and the discovery of
new isotopes are summarized in Ref. 12.

Fig. 1. Photographs of the BigRIPS separator: a) the ﬁrst
stage and b) the second stage.

Fig. 2. A photograph of the ZeroDegree spectrometer.

Fig. 3. A photograph of the SAMURAI spectrometer.
∗1∗2

Director of Research Instruments Group, RIKEN Nishina
Center (2007–2016)
Present address: FRIB/NSCL, Michigan State University

S-61

RIKEN Accel. Prog. Rep. 50 (2017)

Research Activities 1991–2016

References
1) T. Kubo, Nucl. Instrum. Methods Phys. Res. B 204,97 (2003).
2) T. Kubo et al., Prog. Theor. Exp. Phys. 2012, 03C003(2012).
3) H. Sato et al., IEEE Trans. Appl. Supercond. 23,4500308 (2013).
4) T. Kobayashi et al., Nucl. Instrum. Methods Phys.
Res. B 317, 294 (2013).
5) T. Kawabata et al, Nucl. Instrum. Methods Phys. Res.
B 266, 4201 (2008).
6) S. Michimasa et al., Nucl. Instrum. Methods Phys.
Res. B 317, 305 (2013).
7) T. Kubo et al., IEEE Trans. Appl., Supercond. 17,1069 (2007).
8) A. Yoshida et al., Nucl. Instrum. Methods Phys. Res.
A 655, 10 (2011).
9) K. Yoshida et al., Nucl. Instrum. Methods Phys. Res.
B 317, 373 (2013).
10) H. Kumagai et al., Nucl. Instrum. Methods Phys. Res.
B 317, 717 (2013).
11) H. Baba et al., Nucl. Instrum. Methods Phys. Res. A
616, (2010) 65.
12) T. Kubo, Nucl. Instrum. Methods Phys. Res. B 376,102 (2016).
13) H. Takeda et al., Nucl. Instrum. Methods Phys. Res.
B 317, 798 (2013).
14) N. Fukuda et al., Nucl. Instrum. Methods Phys. Res.
B 317, 323 (2013).
15) Y. Sato et al., JPS Conf. Proc. 6, 030124 (2015).
16) H. Suzuki et al., Nucl. Instrum. Methods Phys. Res. B
317, 756 (2013).
17) T. Ohnishi et al., J. Phys. Soc. Jpn. 77, 083201 (2008).
18) T. Ohnishi et al., J. Phys. Soc. Jpn. 79, 073201 (2010).
19) T. Sumikama et al., Phys. Rev. C 95, 051601(R)(2017).
20) D. Kameda et al., Phys. Rev. C 86, 054319 (2012).

S-62