Speaker
Description
At RIKEN RIBF, the development of 28-GHz superconducting electron cyclotron resonance ion sources (SC-ECRIS) [1] is crucial for advancing high-intensity beams of various ion species for scientific, industrial and medical applications. To achieve the RIBF upgrade's core goal [2] of extracting a 2-particle ${\mu}$A uranium (U) beam from the superconducting ring cyclotron (SRC), it is essential to develop a novel Charge Stripper Ring (CSR) [3] to significantly enhance charge stripping efficiency, and to generate 300-$\mu$A U$^{35+}$ beam from the SC-ECRIS. To achieve this goal, we are developing several technologies to confine high-electron-temperature, high-density ECR plasma. This includes the introduction of GM-JT cryocoolers exceeding 8W capable of withstanding X-ray heat loads on the SC mirror coils, the development of a gyrotron for ECR plasma heating, and the design of an oven [4] as a solid sample evaporator in the SC-ECRIS. Especially, the oven heated by high current of around 600 A, was designed with careful consideration of stresses caused by the mirror field exceeding 2 T. These advances aim to significantly enhance intensity and stability across a wide range of ion species. Furthermore, to enhance beam quality, a new analysis method using Pepper Pot Emittance Meter (PPEM) was developed [5] for advanced beam diagnostics. This approach facilitates further improvements in the quality of non-Gaussian beams influenced by the complex fringe field of the ECRIS mirror.
Footnotes
[1] T. Nakagawa et al., Rev. Sci. Instrum., vol. 81, 02A320, 2010.
[2] https://www.nishina.riken.jp/researcher/RIBFupgrade/index_e.html
[3] H. Imao et al., J. Inst. 15, P12036, (2020).
[4] J. Ohnishi et al., Proc. ECRIS2018, Catania, Italy, Sep. 2018, pp. 180−184.
[5] Y. Morita et al., J. Phys: Conf. Ser. 2743, 012071, 2024.
