An electrostatic time-of-flight detector named E-MCP has been developed for quick diagnostics of circulating beam and timing measurement in mass spectrometry at the Rare-RI Ring in RIKEN. The E-MCP detector consists of a conversion foil, potential grids, and a microchannel plate. Secondary electrons are released from the surface of the foil when a heavy ion hits it. The electrons are accelerated and deflected by 90∘ toward the microchannel plate by electrostatic potentials. A thin carbon foil and a thin aluminum-coated mylar foil were used as conversion foils. We obtained time resolutions of 69(1) ps and 43(1) ps (standard deviation) for a 84Kr beam at an energy of 170 MeV/u when using the carbon and the aluminum-coated mylar foils, respectively. A detection efficiency of approximately 90% was obtained for both foils. The E-MCP detector equipped with the carbon foil was installed inside the Rare-RI Ring to confirm particle circulation within a demonstration experiment on mass measurements of nuclei around 78Ge produced by in-flight fission of uranium beam at the RI Beam Factory in RIKEN. Periodic time signals from circulating ions were clearly observed. Revolution times for 78Ge, 77Ga, and 76Zn were obtained. The results confirmed successful circulation of the short-lived nuclei inside the Rare-RI Ring.
@article{arxiv.2011.02479,
title = {Development and operation of an electrostatic time-of-flight detector for the Rare RI storage Ring},
author = {D. Nagae and Y. Abe and S. Okada and S. Omika and K. Wakayama and S. Hosoi and S. Suzuki and T. Moriguchi and M. Amano and D. Kamioka and Z. Ge and S. Naimi and F. Suzaki and N. Tadano and R. Igosawa and K. Inomata and H. Arakawa and K. Nishimuro and T. Fujii and T. Mitsui and Y. Yanagisawa and H. Baba and S. Michimasa and S. Ota and G. Lorusso and Yu. A. Litvinov and A. Ozawa and T. Uesaka and T. Yamaguchi and Y. Yamaguchi and M. Wakasugi},
journal= {arXiv preprint arXiv:2011.02479},
year = {2020}
}