Novel method for the production of spin-aligned RI beams in projectile fragmentation reaction with the dispersion matchi
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Novel method for the production of spin-aligned RI beams in projectile fragmentation reaction with the dispersion matching technique Y. Ichikawa · H. Ueno · Y. Ishii · T. Furukawa · A. Yoshimi · D. Kameda · H. Watanabe · N. Aoi · K. Asahi · D. L. Balabanski · R. Chevrier · J. M. Daugas · N. Fukuda · G. Georgiev · H. Hayashi · H. Iijima · N. Inabe · T. Inoue · M. Ishihara · T. Kubo · T. Nanao · T. Ohnishi · K. Suzuki · M. Tsuchiya · H. Takeda · M. M. Rajabali Published online: 1 November 2012 © Springer Science+Business Media Dordrecht 2012
Abstract A novel method to produce spin-aligned rare-isotope (RI) beam has been developed, that is the two-step projectile fragmentation method with a technique of dispersion matching. The present method was verified in an experiment at the RIKEN RIBF, where an RI beam of 32 Al with spin alignment of 8(1) % was successfully produced from a primary beam of 48 Ca, with 33 Al as an intermediate nucleus. Figure of merit of the present method was found to be improved by a factor larger than 50 compared with a conventional method employing single-step projectile fragmentation.
Y.I. is grateful to the Special Postdoctoral Researchers Program, RIKEN. This work was partly supported by the JSPS KAKENHI (22340071 and 20532089), by the JSPS and MAEE under the Japan-France Integrated Action Program (SAKURA), and by the Bulgarian National Fund (grant DID-02/16). Y. Ichikawa (B) · H. Ueno · D. Kameda · H. Watanabe · N. Aoi · N. Fukuda · N. Inabe · M. Ishihara · T. Kubo · T. Ohnishi · T. Takeda RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan e-mail: [email protected] Present Address: Y. Ichikawa Department of Physics, Tokyo Institute of Technology, 2-12-1 Oh-okayama, Meguro, Tokyo 152-8551, Japan Y. Ishii · K. Asahi · H. Hayashi · H. Iijima · T. Inoue · T. Nanao · K. Suzuki · M. Tsuchiya Department of Physics, Tokyo Institute of Technology, 2-12-1 Oh-okayama, Meguro, Tokyo 152-8551, Japan T. Furukawa Department of Physics, Tokyo Metropolitan University, 1-1 Minami-Ohsawa, Hachioji, Tokyo 192-0397, Japan A. Yoshimi Research Core for Extreme Quantum World, Okayama University, 3-1-1 Tsushimanaka, Kita, Okayama 700-8530, Japan
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Y. Ichikawa et al.
Keywords Nuclear spin · Nuclear moment · RI beam
1 Introduction The technique of spin orientation in rare-isotope (RI) beam has been played important roles in the study on nuclear structure through the measurement of nuclear electromagnetic moments as well as in application to material sciences [1, 2]. The mechanism of the spin orientation in a projectile fragmentation (PF) reaction was first revealed in 1990 [3]. The fragmentation of a projectile nucleus in highenergy nucleus-nucleus collisions is described remarkably well by a simple model of “participant-spectator” [4]. In the model, the projectile fragment acquires an angular momentum whose orientation is determined as a function of the momentum of the outgoing fragment. This implies a unique relation between the spin orientation and the direction of the removed momen
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