Ⅵ. ORGANIZATION AND ACTIVITIES OF RNC

RIKEN Accel. Prog. Rep. 56 (2023)

Nuclear Science and Transmutation Research Division
Nuclear Transmutation Data Research Group
Slow RI Data Team
1. Abstract

This team is in charge of the development of low-energy RI beams of long-lived ﬁssion fragments (LLFP) or minor actinides(MA) from the 238 U by means of degrading the energy of beams produced by the BigRIPS fragment separator.

2. Major Research Subjects

Studies of the slowing down and puriﬁcation of RI beams are the main subjects of the team. Developments of devices used forthe slowing down of RI beams are also an important subject.
(1) Study and development of the slowed-down methods for LLFP(2) Operation of the BigRIPS separator and supply the low energy LLFP beam to the experiment in which the cross sections ofLLFP are measured at the low energy.
(3) Development of MA (such as Np) beams for the nuclear data
(4) Development of the framework to seamlessly handle device, detector, DAQ, and analysis for the easy control of the complicate
slowed-down RI beam production and its development.

3. Summary of Research Activity

A new OEDO beam line, designed for the slowed-down RI beams, was constructed under the collaboration with CNS, the University of Tokyo. Our group was responsible for the construction of the infrastructure such as the cooling water and the electricalequipment, and the movement and alignment of existing vacuum chambers, quadrupole magnets. The power supply for the Superconducting Triplet Quadrupoles (STQ) was made, which had a stability also under the low current condition.
Slowed-down 93 Zr beams with 20 or 50 MeV/nucleon were successfully developed in June 2016 for the ﬁrst time. The methods
to obtain the narrow energy, position, and angle distribution were developed. The methods of the energy adjustment and the particle
identiﬁcation at 50 MeV/nucleon were developed. The 93 Zr and 107 Pd beams with 50 MeV/nucleon were produced for the nucleartransmutation experiments using proton or deuteron targets in October 2016. The commissioning experiment of the OEDO beam line
was successfully performed in June 2017. The ﬁrst transmutation experiments using OEDO beam line were performed with 93 Zr,107
Pd, and 79 Se around 20 MeV/nucleon.
With our developments, the slowed-down RI beams became ready for the transmutation experiments. On the other hand, theprocedure to make the slowed-down RI beams became highly specialized. To easily produce the slowed-down RI beam, the framework,called BYACO, is being developed to seamlessly handle the device, detector, DAQ, and analysis. The procedure of the RI-beam energy
control was implemented in the web application. The BYACO system was used also for an RI-beam automatic tuning project by theBigRIPS team. The automatic tuning of the RI beam becomes one of the categories in the RNC’s use case of the TRIP project.
BYACO needs to be upgraded when the automatic tuning is used under the operation. Future developments were considered in 2022.
The extension of the RI-beam separation using the Bρ-∆E-Bρ method by the charge state of RI beam was found to be essential toproduce the heavy RI beams. The simulation tool of this extended separation, called Q+ separation, was developed and implemented
into BYACO in 2021. With this tool, we succeeded to produce a 237 Np beam as a secondary beam by collaborating mainly with thefast RI data team and the BigRIPS team.

Members
Team Leader
Toshiyuki SUMIKAMA
Visiting Scientist
SungHan BAE (Inst. for Basic Sci.)
Student Trainee
Masaya OISHI (Kyushu Univ.)

List of Presentation
Presentation[Domestic Conference/Workshop]

炭竃聡之（招待講演）, 「理研・低速 RI データチームから」, 原子核物理学実験におけるデータ利活用による研究戦略, オンライン,
2022 年 3 月 7 日.

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