16-21 September 2018
CERN
Europe/Zurich timezone

Development of a new in-ring beam monitor in the Rare-RI Ring

18 Sep 2018, 16:45
2h
500/1-201 - Mezzanine (CERN)

500/1-201 - Mezzanine

CERN

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Poster Instrumentation for radioactive ion beam experiments Poster Session 2

Speaker

Mr Shunichiro Omika (RIKEN, Saitama Univ.)

Description

The precise masses of neutron-rich nuclei are important for the study of the r-process nucleosynthesis as well as nuclear structure far from stability. The newly constructed storage ring, Rare-RI Ring, is a device dedicated for the precise mass measurements for short-lived nuclei [1][2]. The masses are determined by comparing the revolution time of a reference particle with known mass and that of a particle of interest with unknown mass, based on the isochronous mass spectrometry.
To adjust several magnets in the injection orbit properly, we need a detector to confirm the circulation of the stored particle. The detector should be sensitive to a single ion because the Rare-RI Ring handles only one particle at each injection. In addition, it is necessary to measure the revolution time to adjust the isochronous magnetic field precisely using a narrow-band Schottky pick-up [3]. Therefore, we developed a new in-ring beam monitor which consists of a thin foil, a scintillator, and multi-pixel photon counters (MPPCs) [4].
The operation principle is based on the secondary electrons including delta-rays which are generated when the stored particle passes through the foil at each revolution. The secondary electrons are detected by a scintillator coupled with MPPCs without any guiding field. We carried out beam experiments to verify the principle for a prototype detector at the Heavy-Ion Medical Accelerator in Chiba (HIMAC) synchrotron facility.
After verification, we installed the detector in the ring. The detector consists of a 3-$\mu$m-thick aluminum foil, one large plastic scintillator (100 × 100 mm$^{2}$ with 3-mm thickness) and two small ones (80 ×50 mm$^{2}$ with 3-mm thickness), and 10 MPPCs (S12572-100C) for scintillation light readout. In November 2016, we conducted a machine study of the Rare-RI Ring and successfully measured revolution times using present detector. The result showed that the revolution time was determined in a precision of 8.0 × 10$^{-4}$.
In this contribution, we will present the details of the experiments, analysis, and results.

References
[1] A. Ozawa et al., Prog. Theor. Exp. Phys. 2012, 03C009 (2012).
[2] Y. Yamaguchi et al., Nucl. Instrum. Methods. Phys. Res. B 317, 629 (2013).
[3] F. Suzaki et al., RIKEN Accel. Prog. Rep. 49, 179 (2016).
[4] S. Omika et al., RIKEN Accel. Prog. Rep. 50, in press.

Primary author

Mr Shunichiro Omika (RIKEN, Saitama Univ.)

Co-authors

Prof. Akira Ozawa (Univ. of Tsukuba) Mr Daiki Kamioka (Univ. of Tsukuba) Dr Daisuke Nagae (RIKEN Nishina Center) Dr Fumi Suzaki (RIKEN Nishina Center) Mr Kiyoshi Wakayama (Saitama Univ.) Mr Masamichi Amano (Univ. of Tsukuba) Dr Masanori Wakasugi (RIKEN Nishina Center) Ms Natsuki Tadano (Saitama Univ.) Dr Sarah Naimi (RIKEN Nishina Center) Dr Shinji Suzuki (Univ. of Tsukuba) Prof. Takayuki Yamaguchi (Saitama Univ.) Prof. Takeshi Suzuki (Saitama Univ.) Dr Tetsuaki Moriguchi (Univ. of Tsukuba) Dr Tomohiro Uesaka (RIKEN Nishina Center) Dr Yasushi Abe (RIKEN Nishina Center) Dr Yoshitaka Yamaguchi (RIKEN Nishina Center) Mr Zhuang Ge (RIKEN, Saitama Univ.)

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