PREFACEThe RIKEN Accelerator Progress
Report is the annual report of all theresearch activities conducted at theRIKEN
Nishina
CenterforAccelerator-Based Science (RNC).
This volume (No. 56) covers theactivities conducted during theJapanese fiscal year 2022 (i.e., April
2022 to March 2023).
With restrictions on social
activity due to the coronavirus
pandemic being gradually eased lastyear, we have been able to reconnect
with friends and families in person
for the first time since the spring of2020. The same was true researchwise, with many researchers fromabroad visiting to RIKEN toparticipate in the experiments
scheduled at the end of the year. At
the end of October 2022, “TheYoshio Nishina Memorial Event” was successfully held in person as well. With the attendance of guests related to or
have connection with Dr. Nishina who came all the way to Wako, the event turned out to be a great opportunity to sparkinterest not just among the participants but to a wider community about Dr. Nishina’s achievements and the Nishina
Center’s latest initiatives and research activities.
One of the messages that we wanted to communicate through “The Nishina Yoshio Memorial Laboratory” is the“Copenhagen Spirit” that took hold in the research field pioneered by Dr. Nishina. The Spirit is still very much alive inJapan, and I think the main reason is because it matches the philosophy of “Yaoyorozu no kami (eight million gods),” a
traditional Japanese belief that says god exists in everything. Because individual’s ideas and curiosity are the base ofscience and technology, each one can be called a Creator. Every social activity should acknowledge and embracedifferences in one’s sensibility and heighten each other’s originality. It is my wish that we will contribute to realizing apeaceful society where individuals can shine, an endeavor to be achieved when the essence and role of science andtechnology are fully incorporated into society while not repeating the mistakes made about 80 years ago.
95 years later, since the first cyclotron built by Dr. Yoshio Nishina, the superconducting ring cyclotron (SRC) wasregistered in the Guinness World Records in April 2022, as the highest energy beam cyclotron which achieves 82,400
MeV of a uranium beam. The SRC was constructed with advanced technology from Japanese industries and completedin 2006. Since then, the uranium beam has been utilized in more than 100 publications. The other beams also have madea significant contribution to the development of the low energy nuclear physics.
Yasuki Akiba has been appointed as the Director of RHIC Physics Research Group to conduct the sPHENIX
program at RHIC as of April 2022. Tetsuya Ohnishi has succeeded, as the Director of Instrumentation Development
Group as of October 2022. Yoshihide Higurashi has been appointed as the Team Leader of RILAC Team as of October
2022.
In March 2023, an event celebrating three decades of collaboration between RAL and RIKEN was organized. TheRIKEN-RAL Muon Facility was concluded at the end of March. The muon programs have produced over 500
publications, including muon-catalyzed fusion, condensed matter physics and chemistry and battery materials, and havemade new departures in international collaborations, involving South-East Asian countries such as Indonesia, Malaysia,and Thailand. A new partnership between ISIS RNC has been established since April 2023 to encourage collaborationin areas of accelerator-based sciences.
Many outstanding research results were obtained at RNC last year. Twelve press releases were disseminated in
FY2022. Selected strides made in 2022 have been compiled in the “Highlights of the Year” section in this volume,
which show successful multi-disciplinary activities of RNC for science, technology, and innovation. One of thehighlights was the successful observation of four neutron states by using a different method to observe the phenomenon
already observed few years ago. This research achievement has been chosen by the Institute of Physics as one of the“Top 10 Breakthroughs of the Year for 2022.” The discovery of 39Na was featured by the YouTube program of“Periodic Table of Videos.” The first mass measurement with Rare-RI Ring was published to give an impact to the r-