MO4 —  Monday Session 4   (27-Jun-22   16:00—17:30)
Chair: F.R. Osswald, IPHC, Strasbourg Cedex 2, France
Paper Title Page
High Beam Power Operations at RIKEN RIBF: Technical Developments, Challenges and Resolutions  
  • O. Kamigaito, T. Dantsuka, H. Fujii, M. Fujimaki, N. Fukunishi, H. Hasebe, Y. Higurashi, H. Imao, M. Kidera, M. Komiyama, K. Kumagai, T. Maie, T. Nagatomo, T. Nakagawa, M. Nakamura, T. Nishi, J. Ohnishi, H. Okuno, K. Ozeki, N. Sakamoto, K. Suda, A. Uchiyama, T. Watanabe, Y. Watanabe, K. Yamada
    RIKEN Nishina Center, Wako, Japan
  • T. Adachi, Y.M. Miyake
    RIKEN, Saitama, Japan
  The Radioactive Isotope Beam Factory (RIBF) of RIKEN is a cyclotron-based heavy ion accelerator facility, which can accelerate heavy ions including uranium up to 345 MeV/u using an accelerator complex with a K2600-MeV Superconducting Ring Cyclotron (SRC) in the last stage to produce rare isotope beams in an in-flight technique. The first beam was obtained in 2006, and the beam service to the users was started in the following year. In the 15 years of developments since then, the intensity and stability of the heavy-ion beams have been significantly improved. For example, the uranium beam extracted from SRC reached 117 pnA with a beam power of 9.6 kW, exceeding the facility goal of 100 pnA set in 2011. Additionally, 70Zn beams have reached an intensity of 788 pnA and a beam power of 19.0 kW. The availability of the accelerator has also exceeded 90¥%. Various scientific results on unstable nuclei have been produced by such beams. The core experimental instrumentations, such as the Rare RI Ring, are now in operation, and further results are expected in the future. This paper will discuss the various technological developments that have been made since the start of RIBF acceleration and will provide future directions.  
slides icon Slides MO4I1 [5.635 MB]  
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MO4I2 Liquid Lithium Charge Stripper Commissioning with Heavy Ion Beams and Early Operations of FRIB Strippers 31
  • T. Kanemura, N.K. Bultman, R. Madendorp, F. Marti, T. Maruta, Y. Momozaki, J.A. Nolen, P.N. Ostroumov, A.S. Plastun, H.T. Ren, A. Taylor, J. Wei, Q. Zhao
    FRIB, East Lansing, Michigan, USA
  • M.J. LaVere
    MSU, East Lansing, Michigan, USA
  • Y. Momozaki, J.A. Nolen
    ANL, Lemont, Illinois, USA
  Funding: This work is supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
The Facility for Rare Isotope Beams (FRIB) at Michi-gan State University is a 400 kW heavy ion linear accel-erator. Heavy ion accelerators normally include a charge stripper to remove electrons from the beams to increase the charge state of the beams thus to increase the energy gain. Thin carbon foils have been the traditional charge stripper but are limited in power density by the damage they suffer (sublimation and radiation damage) and con-sequently short lifetimes. Because of the high beam pow-er, FRIB had decided to use a liquid lithium charge strip-per (LLCS), a self-replenishing medium that is free from radiation damage. FRIB recently commissioned a LLCS with heavy ion beams (36Ar, 48Ca, 124Xe and 238U beams at energies of 17-20 MeV/u). Since there had been no exper-imental data available of charge stripping characteristics of liquid lithium, this was the first demonstration of charge stripping by a LLCS. The beams were successfully stripped by the LLCS with slightly lower charge states than the carbon foils of the same mass thickness. The LLCS started serving the charge stripper for FRIB user operations with a backup rotating carbon foil charge stripper. FRIB has become the world’s first accelerator that utilizes a LLCS.
slides icon Slides MO4I2 [6.337 MB]  
DOI • reference for this paper ※  
About • Received ※ 26 June 2022 — Revised ※ 27 June 2022 — Accepted ※ 01 July 2022 — Issue date ※ 10 August 2022
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MO4C3 Development, Fabrication and Testing of the RF-Kicker for the Acculinna-2 Fragment Separator 37
  • W. Beeckman, F. Forest, O. Tasset-Maye, E.J. Voisin
    SIGMAPHI S.A., Vannes, France
  • A. Bechtold
    NTG Neue Technologien GmbH & Co KG, Gelnhausen, Germany
  • A.S. Fomichev, A.V. Gorshkov, S.A. Krupko, G.M. Ter-Akopian
    JINR/FLNR, Moscow region, Russia
  The Acculinna-2 radioactive beam separator was designed and built between 2012 and 2014, then installed and tested by Sigmaphi in 2015 and in full operation since 2016 at the Flerov laboratory of JINR in Dubna. In order to achieve efficient separation of neutron-deficient species, an RF kicker was foreseen since the beginning of the project but was put on hold for many years. In 2016 Sigmaphi got a contract to study, build, install and test an RF kicker with a variable frequency ranging between 15 and 21 MHz and capable of producing 15kV/cm transverse electric fields in a 10 cm gap over a 1m long distance.# The presentation first recalls the rationale of an RF-kicker to separate neutron-deficient species. It then goes through the different steps of the study, initial choice of the cavity structure, first dimensioning from analytical formulas, finite elements computations and tuning methods envisioned, down to a final preliminary design.# A 1/10 scaled mock-up of this final shape was built and tested as a check before building the full-size cavity. The NTG company was then contracted to perform, in a joint collaboration with Sigmaphi, the final study, detailed design, construction and factory testing of the real cavity. The presentation highlights the fabrication and tests of both mock-up and real size cavities through a series of pictures.# The complete RF-kicker, with its power supply, control and pumping systems was installed on the Acculinna-2 beamline in June 2019. Because the U400M cyclotron was due to shut down by mid-2020, the Acculinna-2 team decided to use the separator to accumulate as much data as possible, to be processed during the 2 years closing time. A 1-week time window for kicker testing was only available in February 2020, a short but sufficient time lapse to successfully drive the cavity at full power and test it over a wide frequency range. Unfortunately, because of cyclotron closure, no beam tests have been performed so far. The latest availabl  
slides icon Slides MO4C3 [16.742 MB]  
DOI • reference for this paper ※  
About • Received ※ 26 June 2022 — Revised ※ 10 August 2022 — Accepted ※ 15 September 2022 — Issue date ※ 29 September 2022
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