Ⅴ. EVENTSRIKEN Accel. Prog. Rep. 53

Nishina School 2019
H. Ishiyama,∗1 T. Motobayashi,∗1 and H. Ueno∗2
Nishina School aims at introducing nuclear physics research to Asian university students who are choosing
their future ﬁeld of study. In 2019, the 13th Nishina
School was held from July 30 to August 9. This period was made slightly later than usual to make it easier for Japanese students to participate after their termend examinations. Students and supervisors from Peking
University (PKU), the University of Hong Kong (HKU),
Seoul National University, Rikkyo University, and Tohoku University joined Nishina School this year. Highschool students from Philips Exeter Academy, USA,
along with their teacher, participated in most of the
School programs. Figure 1 shows all 22 students andSchool staﬀ members.
The School began with self-introductions of the students. The ﬁrst week was dedicated mostly to lectures
and training on a few subjects related to a nuclear reaction experiment that was performed in the second weekof the School. The lectures were on a few basic topics forresearch, including overviews of nuclear physics and nuclear astrophysics, as well as methods of radiation measurements. Another lecture was dedicated to radiation
safety. The training subjects were electronic-pulse propagation and radiation detection. The training covered
the detectors, electronics, and data acquisition system
to be used in the experiment in the following week.
The program in the second week focused on a reaction
experiment using proton beams from the Pelletron accelerator at RIKEN Nishina Center. The students weredivided into six groups, which oversaw six diﬀerent typesof measurements. They started to design the experimentby evaluating the feasibility of measurements (i.e., estimation of γ-ray yields, etc.), following which they set thedetectors around the reaction target and determined theconditions of beam exposure based on their considerations. After the experiment, they analyzed the experimental data obtained and ﬁnally made presentations on

Fig. 1. Participants of Nishina School 2019.
∗1∗2

School Master
Chair, Nishina School Steering Committee

Fig. 2. Photograph of the experimental apparatus. The 12 C
or BN target in the vacuum pipe at the center of photograph was irradiated with proton beams from the Pelletron accelerator. The NaI detector at upper side of thephotograph detected γ-rays generated by the reactions.

Fig. 3. Example of the γ-ray spectra obtained for the “inbeam” measurement of the 12 C(p, γ)13 N reaction with a
2-MeV proton beam.

their results. They studied the low-energy 12 C(p, γ)13 N
or 10 B(p, α)7 Be reaction, which are related to nucleosynthesis in stars.
Figure 2 shows the experimental apparatus. Proton
beams with an energy of 1 or 2 MeV bombarded a carbon or boron nitride target, which stopped the protons toprovide a so-called thick target yield of those reactions.
Two methods were employed to determine the resonanceyield: the detection of “in-beam” γ-rays from 13 N or 7 Be
excited states and the detection of 511-keV γ-rays fromthe β + decay of 13 N or 7 Be activities, which is known as
the “activation” technique. Figure 3 shows an example ofthe obtained γ-ray spectrum for the “in-beam” measurement of the 12 C(p, γ)13 N reaction. Two distinct peaks ofrelevance in the experiment are clearly observed. The six
teams could ﬁnally extract the reaction cross sections.
We thank all the staﬀ members of the Nishina Center
who participated and helped in Nishina School 2019.
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Ⅴ. EVENTSRIKEN Accel. Prog. Rep. 53

Creation of superheavy elements highlighted at the closing ceremony of
IYPT 2019†
H. En’yo,∗1
The year, 2019 was the International Year of the Periodic Table (IYPT). It marked the celebration of the150th anniversary of Mendeleev’s periodic table and thecompletion of the 7th row of the table. The opening
ceremony took place on January 29th at the UNESCO
HQ in Paris, and the closing ceremony took place on
December 5th at the Tokyo Prince Hotel. The closing
ceremony was hosted by the Chemical Society of Japan,
Science Council of Japan, and RIKEN on behalf of UNESCO, IUPAC, and IUPAP.
The closing ceremony included an impressive list of
exhibitions and sessions; it started with an opening session, followed by sessions titled “Introduction of IYPT
activities” and “Discoveries and Creation of elements,”
and ended with a session titled “Periodic Table for Next
Generations.” The event also had musical performances,including one by an orchestra comprised of Japanesechemists. The entire program was recorded and can beviewed on the web page of IYPT of Japan.1)
An important session for Nishina Center was the “Creation of Superheavy Elements,” which started with the
piano fantasy “Nihonium” played by a high school student Honoka Motai. Miss Motai is so devoted to theperiodic table that the discovery of nihonium inspired
her to compose the music she performed. Her beautiful
music was accompanied by a screen showing the landscape of Nihonium Avenue stretching from Wako City
Station to RIKEN.2) This avenue is a “walk of fame”
of about 15 min for the 118 elements from hydrogento oganesson, which are displayed in paving stones andlead to the entrance of RIKEN, where a large monument
dedicated to nihonium is installed.

After the piano performance, celebrated speeches were
given with institutional introductory movies. This included Victor Matveev for the Joint Institute for Nuclear
Research, Karlheinz Langanke for GSI Helmholtzzentrum für Schwerionenforschung, Roderick Clark for
Lawrence Berkeley National Laboratory, Mark Stoyer
for Lawrence Livermore National Laboratory, Krzysztof
Rykaczewski for Oak Ridge National Laboratory, Kosuke Morita for RIKEN Nishina Center, and a final speech given by Yuri Oganessian representing all
the discoverers. Lastly, the boards of 15 superheavy
elements from Rf (Z = 104) to Og (Z = 118)
are shown in line by M. Itkis (JINR), V. Matveev(JINR), R. Clark (LBNL), A. Yakushev (GSI), C. Duellmann (GSI, JGUM), M. Block (GSI, JGUM), K. Langanke (GSI), D. Ackermann (GANIL), J. Khuyagbaatar(GSI), M. Honoka (Tokyo Gakugei University SeniorHigh School) with K. Morimoto (RIKEN), S. Dmitriev(FLNR, JINR), V. Utyonkov (FLNR, JINR), M. Stoyer(LLNL), K. Rykaczewski (ORNL), and A. Karpov(FLNR, JINR), respectively.
These scientists had participated in both this ceremony and the 4th International Symposium on Superheavy Elements (SHE2019), held from 1–5 December at
Hakone. H. Haba (RIKEN) and K. Morita (Kyushu-U,
RIKEN) jointly chaired the symposium.
References

1) https://iypt.jp/ .
2) The video was created by N. Miya-uchi, RIKEN Nishina
Center, and can be obtained upon request.

Fig. 1. The boards of 15 superheavy elements from Rf to Og displayed by discoverers.
†∗1

Condensed from the article in Nucl. Phys. News 30, 1 (2020)
RIKEN Nishina Center- 228 -

Ⅴ. EVENTSRIKEN Accel. Prog. Rep. 53

The 3rd “Hodan-kai” meeting for the future of exotic nuclear physics
W. Horiuchi,∗1,∗2 Y. Ichikawa,∗3,∗4 K. Sekizawa,∗5 and D. Suzuki∗3 for the “Hodan-kai” meeting organizers
The third “Hodan-kai” meeting by young researchers
was held from February 19 to 21, 2020 at the Integrated
Innovation Building in Kobe campus of RIKEN, whichis the same venue as for the previous Hodan-kai meetings. This Hodan-kai was the third in the meeting
series organized by RIBF Theory Forum and RIKEN
Nishina Center, and supported by RIKEN iTHEMS
and JICFuS. The style of Hodan-kai is diﬀerent fromthat of an ordinary workshop in which recent researchworks are presented by the respective research groups.
This meeting aims to facilitate the exchange of new
ideas among young researchers, including unmatured
ideas and dreams that are not feasible at present.
Given the spirit of the meeting, the presentation ﬁles
are disclosed to the public. Furthermore, the venue islocated in a rather isolated place, which enables participants to concentrate on physics discussions. The
meeting always exceeds the scheduled time owing topassionate discussions among the participants.
The ﬁrst Hodan-kai was held from July 21 to August
2, 2017, and focused mainly on the latest theoretical research on nuclear physics. The number of participants
was 49 with 23 presentations. The second meeting washeld from February 18 to 20, 2019 and had 42 participants. While limiting the number of presentations to
25, the topic was extended: 6 presentations were madeby theoretical nuclear physicists, 7 presentations by
experimental nuclear physicists, and 12 presentations
by researchers in other ﬁelds that may closely be re-Fig. 2. Photograph of a panel discussion.

lated to nuclear physics. The program and summaryof the ﬁrst and second Hodan-kai were shared on theirrespective websites.1,2)
In the third Hodan-kai, we had 43 participants and17 presentations by young researchers including 6 and
7 presentations by theoretical and experimental nuclear physicists, respectively, and 4 presentations byresearchers in other ﬁelds. In addition to these talks
given in the regular Hodan-kai style, we newly organized two “panel discussion” sections to facilitate interaction among the participants. In the panel discussions, introductory talks on “New textbook for nuclear
physics” and “What is cooling?” were given by theorganizers, and 5–7 short talks were given by invited
panelists. Though, as always, these exciting discussions easily exceeded the scheduled time, the meeting
ended sucessfully while keeping the spirit of Hodan-kai.
The full program and summary of the third Hodan-kai
can be found on its website.3) Figures 1 and 2 show
some snapshots of the 3rd Hodan-kai. Attracting more
students to this meeting is one of the key ingredientsfor the success of “Hodan-kai.” We plan to hold thenext Hodan-kai in February 2021 and look forward to
having more participants.
References

Fig. 1. Group photograph of the 3rd “Hodan-kai” meeting.
∗1
∗2
∗3
∗4
∗5

Department of Physics, Hokkaido University
RIBF Theory ForumRIKEN Nishina Center
Department of Physics, Kyushu University
Center for Transdisciplinary Research, Institute for Research Promotion, Niigata University- 229 -

1) 1st Hodan-kai:
2509/ .
2) 2nd Hodan-kai:
2864/ .
3) 3rd Hodan-kai:
3157/ .

https://indico2.riken.jp/event/
https://indico2.riken.jp/event/
https://indico2.riken.jp/event/Ⅴ. EVENTSRIKEN Accel. Prog. Rep. 53

SHE2019—The 4th International Symposium on Superheavy Elements
H. Haba on behalf of the SHE2019 Local Organizing Committee∗1
The 4th International Symposium on Superheavy
Elements (SHE2019) was held on December 1–5, 2019
at The Prince Hakone Lake Ashinoko in Hakone,
Japan. Hakone is close to Tokyo, situated at the footof Mount Fuji, and one of the most popular travel
destinations among Japanese and foreign tourists.
SHE2019 followed the previous symposiums at Texas
A&M University, USA in 2013 and 2015 and Kazimierz
Dolny, Poland in 2017. This symposium was jointly organized by the RIKEN Nishina Center, Research Center for Superheavy Elements, Kyushu University, andAdvanced Science Research Center, Japan Atomic Energy Agency. It had 130 registrants from 16 countries.
There were 2 plenary, 33 invited, and 27 oral talks, aswell as 14 poster presentations.
SHE2019 covered all theoretical and experimental
aspects of superheavy nuclei and atoms. SHE2019
started with two plenary talks titled “SHE2019 Symposium: experimental challenges” by Y. Oganessianand “Superheavy elements: theoretical challenge” by
W. Nazarewicz of Michigan State University, USA on
the evening of December 1. From the morning of December 2 till the evening of December 4, the following scientific sessions were conducted: 1) Reaction of
Synthesis of the Heaviest and Neutron-rich Nuclei; 2)
Status and Short-term Plans at SHE Facilities; 3) Nu-

cleosynthesis of SHE and Search in Nature; 4) Properties and Structure of the SHN; and Decays, 5) Heavy
Atoms and Chemistry of SHE; 6) New Approaches and
Setups; and 7) New Facilities, Setups, and Instrumentations. On the evening of December 2–4, Young Scientists sessions were held to give young scientists as
many opportunities for oral presentation as possible.
The excursion of SHE2019 was conducted in theafternoon on December 4. The participants visited
Hakone Lake to enjoy the scenery, Hakone Sekisho(checkpoint) to experience the history, and Hakone
Shrine to explore the local culture and religion.
The year 2019 marked the 150th anniversary of the
discovery of the periodicity of chemical elements by
Dmitrij Ivanovich Mendelejev. Thus, the United Nations and UNESCO proclaimed 2019 as the “International Year of the Periodic Table of Chemical Elements(IYPT2019).” The Closing Ceremony of IYPT washeld at The Tokyo Prince Hotel in Tokyo, Japan on December 5th, immediately after SHE2019. Most of the
SHE2019 participants joined the Closing Ceremony of
IYPT and celebrated the discoveries of elements 113,
115, 117, and 118—nihonium (Nh), moscovium (Mc),tennessine (Ts), and oganesson (Og), respectively—
and the completion of the 7th period of the periodic
table.

Fig. 1. Conference photo taken at a garden of The Prince Hakone Lake Ashinoko on December 4, 2019c(⃝Hideto
En’yo).
∗1

RIKEN Nishina Center- 230 -

Ⅴ. EVENTSRIKEN Accel. Prog. Rep. 53

RIKEN Symposium “Trends in ion-beam breeding over the last two
decades and future research”
T. Abe,∗1 Y. Hayashi,∗1 H. Ichida,∗1 K. Ishii,∗1 R. Morita,∗1 K. Tsuneizumi,∗1 M. Izumi,∗1 Y. Shirakawa,∗1
S. Ohbu,∗1 M. Yamada,∗1 H. Abe,∗1 K. Ichinose,∗1 and N. Asakawa∗1
The RIKEN Symposium on “Trends in ion-beam
breeding over the last two decades and future research”
was held on 23–24 Jan. 2020 at the RIKEN Wako Campus. It was the 9th RARF/RIBF User’s Meeting on
Biology, which is held once every two years. The Beam
Mutagenesis Group promotes various life-science applications of ion beams from the RI Beam Factory. In
particular, this group develops new techniques to breed
plants and microbes with the use of heavy-ion irradiation. We started collaborations with ﬂower companies
and public agricultural experimental stations in 1996
to investigate the potential uses of heavy-ion beams inapplied plant breeding. As a result, two new ﬂower varieties were obtained from irradiated samples in 1998.
The former is a dahlia having large ﬂowers and a novel
color, and it has been sold in Hiroshima City since theautumn of 2001.1) The latter is a verbena, which issterile, generating no seeds; produces ﬂowers with aprolonged lifespan; and has been marketed since thespring of 2002.2) We formed a consortium for ion-beam
breeding. In 2019, it consisted of 184 domestic and20 overseas user institutions. We have already produced 34 new plant varieties. This meeting was ﬁrst
convened in Jan. 2003 to spread ion-beam breeding
technology, and it consisted of practical research, biology, and special lectures. Practical research is classiﬁed into research on ﬂowers, food crops, microbes, andenvironmental-improving plants such as trees and moss
depending on the irradiation samples. Figure 1 shows
the change in the numbers of participants categorized
by their specialization. The number of ﬂower breeders
has decreased since the early meetings. We found thations with higher LETs, such as Fe, are eﬀective for the
mutation breeding of microbes.3) Two new yeast strains
created in 2010 are currently used by over 20 breweries
to produce high-quality sake in Japan.4) The numberof microbe breeders has increased since 2011. NEXTand SIP programs were started from 2010 and 2014,
respectively. We have been investigating the eﬀects of
LETs ranging from 23 to 640 keV/µm on mutation induction. The highest mutation rate was observed at an
LET of 30 keV/µm (LETmax) in Arabidopsis thaliana 5)
and rice.6) The majority of mutations caused by LETmax irradiation were small deletions that were suﬃcient to disrupt a single gene.7) We have been using
high- throughput DNA sequencing technologies to analyze gene mutations. An increasing number of biologists
have shown that mutants induced by LETmax irradiation have become more useful and important in modern∗1

RIKEN Nishina CenterNo. of participants
130

192

190

Year 2003
I
held
2007

2009
I
2013

2015
I
2019

Biology
Tree
MicrobeFood
crop

FlowerFig. 1. Changes in the specializations of symposium participants from 2003 to 2019.

genetic studies, enabling the discovery of genes.8,9)The symposium began with the history over the lasttwo decades of biology and practical research on ﬂowers
and food crops. In a special issue, Dr. Kang, who belongs to ARTI and KAERI and is the President of the
Korean Society of Breeding Science, introduced “Current status and future prospect of mutation breeding
research in Korea.” The next session was on the results of breeding microbe such as Tricholoma matsutake, baker’s yeast, and microalgae. Finally, we discussed avenues for research on biology and ion-beam
breeding in the next decade. The targets of heavyion breeding have extended from ﬂowers to crops suchas grains and beans, which will contribute to solving
the global problems of food supply and environmental
stress. The next meeting will be held in Jan. 2022.
References

1) M. Hamatani et al., RIKEN Accel. Prog. Rep. 34, 169(2001).
2) T. Kanaya et al., Plant Biotech. 25, 91 (2008).
3) H. Ichida et al., Mut Res. 639, 101 (2008).
4) M. Yokobori et al., RIKEN Accel. Prog. Rep. 45, xxiii(2012).
5) Y. Kazama et al., Plant Biotech. 25, 113 (2008).
6) Y. Hayashii et al., RIKEN Accel. Prog. Rep. 50, 27 (2017).
7) Y. Kazama et al., BMC Plant Biol. 11, 161 (2011).
8) Y. Koide et al., Proc. Natl. Acad. Sci. USA 115, E1955(2018).
9) R. Morita et al., Mol. Breed. 39, 135 (2019).

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Ⅴ. EVENTSRIKEN Accel. Prog. Rep. 53

RIKEN Open Day 2019
H. Haba∗1 and K. Takahashi∗1
RIKEN Open Day, on which many laboratories
showcase their research activities and attractive experimental devices to the public, was held in the RIKEN
Wako campus on April 20, 2019. In the Nishina Center, 17 research groups comprising more than 200 researchers participated in the event, as listed in Table 1.
The cover page of the leaflet that introduced the exhibition content in the Nishina Center is shown in Fig. 1.
The radiation controlled area in the RIBF building was
opened to the public to display the world’s largest superconducting cyclotron SRC, the in-flight RI separator BigRIPS, and other powerful experimental devices,along with the exhibition laboratories.
The year 2019 marked the 150th anniversary of the
discovery of the periodicity of chemical elements by
Dimitry Mendeleev. Thus, the United Nations and
UNESCO proclaimed 2019 as the “International Yearof the Periodic Table of Chemical Elements.” Dr. Kosuke Morita, the director of the Superheavy Element
Research Group, gave a scientific lecture titled “Insearch of further new elements” at the Suzuki Umetaro
Hall. He presented the discovery of element 113, nihonium, and the research plan for the next new element,element 119, at RIBF. The weather on the open day
was very pleasant. A total of 8,253 visitors came to
the RIKEN Wako Campus. Among them, 3,013 visited RIBF.

Fig. 1. Cover of the leaflet provided by the Nishina Center
for RIKEN Open Day 2019.

Table 1. List of the Nishina Center exhibitions on RIKEN Open Day 2019.

Laboratory / Group / Team
Accelerator GroupSLOWRI TeamBigRIPS Team
Rare RI-Ring Team
Spin isospin Laboratory
SAMURAI Team
Nuclear Spectroscopy Laboratory
Radioactive Isotope Physics Laboratory
Nishina Center
Nuclear Chemistry Research TeamIon Beam Breeding TeamSuperheavy Element Research Group
User Liaison GroupSCRIT Team
Radiation Laboratory
Quantum Hadron Physics Laboratory
High Energy Astrophysics Laboratory∗1

Exhibition theme
The World’s Strongest Superconducting Ring Cyclotron
Ion Trap and Ultra-Slow RI Production
Superconducting RI Beam Separator BigRIPS
Precision Mass Measurement in 1 ms
Microscopes for Unstable Nuclei
SAMURAI Magnetic Spectrometer
Tiny Magnets in Materials
Study on Origin of Elements at RIBF
Glass Marble Shooting
Nuclear Chart with LEGO Block
Familiar RI and Useful RI
Creating Amazing Plants
The Discovery of the New Element "Nihonium"
Let's Make Your Nihonium
Handmade Spectrometer
See Radiation with Diffusion Cloud Chamber
Enjoy Spinning a Variety of Tops
Research Activities in the Experimental Hadron Physics
Elementary Particles, Nuclei and the Universe
In Space Now

RIKEN Nishina Center- 232 -

Number of staff
35
4
11
8
13
6
12
9
10
7
6
15
12
7
7
11
13
40

Ⅴ. EVENTSRIKEN Accel. Prog. Rep. 53

Outreach activities outside the Wako campus
N. Miyauchi∗1
The year 2019 marks the 150th anniversary of the discovery of Mendeleev’s periodic law. Further, in 2016,
the names of the four elements up to the 118th, including the 113th element nihonium, were finalized, andthe 7th period of the periodic table was completed. To
commemorate these events, the United Nations General
Assembly and UNESCO declared 2019 as the International Year of Periodic Table (IYPT2019). Accordingly,
various events related to the periodic table were held
globally. In Japan, “the Japan Chemical Society, International Year of Periodic Table 2019 Executive Committee” organized special traveling exhibitions at about 20
locations across the country to familiarize people withthe periodic table. The User Liaison Group held workshops at two locations in these traveling exhibitions.
JST Science Agora in Daiba, Tokyo on Nov. 16–
17
The workshop aimed to build a model of the 113th
element, nihonium. The first workshop was held at a
traveling exhibition booth organized by the Executive
Committee of the International Periodic Table at the
Science Agora1) venue on November 16 and 17, 2019(the Science Agora itself was held for three days, from
November 15 to 17). Specifically, we asked participants
to make a three-dimensional nihonium model using smallbeads, which are a children’s toy, and helped them gain
an understanding of the nucleus and how nihonium was
discovered. Although the nucleus is never visible to thenaked eye, the workshop was an attempt to make people
feel the existence of the nucleus by making a model using
the actual number of protons and neutrons.
This time, owing to the limited size of our booth, only
a few participants could be taught by a researcher. As aresult, the total number of participants was only 44 overtwo days. Although the workshop had the disadvantage
of not being able to handle a large number of people,
it was well received because the participants were able
to talk with actual researchers owing to the face-to-faceseating style.
Ehime Prefectural Science Museum on Jan. 18–
19
The next nihonium workshop was held at anothertraveling exhibition booth organized by the Executive
Committee at the Ehime Prefectural Science Museum2)
on January 18 and 19, 2020 (we were invited for two days
to the traveling exhibition that was conducted from December 14, 2019 to January 26, 2020). The workshop
was a great success because Mr. Yoji Hisamatsu (of thisScience Museum), who directed all the traveling exhibitions, took care of us. More than 100 participants made∗1

RIKEN Nishina Center

Fig. 1. Workshop to make a nihonium model using smallbeads.

Fig. 2. Brief lecture on atomic nuclei and nihonium.

their own models of nihonium over the two days of theworkshop.
RIKEN Osaka Campus Open Day 2019
Apart from the above two traveling exhibitions, weparticipated in the open house of RIKEN’s Osaka campus on November 23, 2019. Various RIKEN Centersfrom all over Japan also participated in the event to introduce their research to people in the Osaka area. We
introduced research at the RNC by using a small 3D
nuclear chart produced by a 3D printer, in addition toposter panels. We had a large audience including children. The exhibition was very successful.
References

1) https://www.jst.go.jp/sis/scienceagora/en/reports/
2019/ .
2) http://www.i-kahaku.jp/index.html .

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