Tilted-foil technique for producing a spin-polarized radioactive isotope beam

Y. Hirayama; M. Mihara; Y. X. Watanabe; S. C. Jeong; H. Miyatake; S. Momota; T. Hashimoto; N. Imai; K. Matsuta; H. Ishiyama; S. Ichikawa; T. Ishii; T. Izumikawa; I. Katayama; H. Kawakami; H. Kawamura; I. Nishinaka; K. Nishio; H. Makii; S. Mitsuoka; A. Osa; Y. Otokawa; T. K. Sato

doi:10.1140/epja/i2012-12054-1

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2024 Impact factor 2.8

Hadrons and Nuclei

Eur. Phys. J. A (2012) 48: 54
https://doi.org/10.1140/epja/i2012-12054-1

Regular Article - Experimental Physics

Tilted-foil technique for producing a spin-polarized radioactive isotope beam

Y. Hirayama¹^*, M. Mihara², Y. X. Watanabe¹, S. C. Jeong¹, H. Miyatake¹, S. Momota³, T. Hashimoto⁴, N. Imai¹, K. Matsuta², H. Ishiyama¹, S. Ichikawa⁴, T. Ishii⁴, T. Izumikawa⁵, I. Katayama¹, H. Kawakami¹, H. Kawamura⁶, I. Nishinaka⁴, K. Nishio⁴, H. Makii⁴, S. Mitsuoka⁴, A. Osa⁴, Y. Otokawa⁴ and T. K. Sato⁴

¹ Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK), 305-0801, Ibaraki, Japan
² Department of Physics, Osaka University, 560-0043, Osaka, Japan
³ Kochi University of Technology, 782-8502, Kochi, Japan
⁴ Japan Atomic Energy Agency (JAEA), 319-1195, Ibaraki, Japan
⁵ Radioisotope Center, Niigata University, 951-8510, Niigata, Japan
⁶ Department of Physics, Rikkyo University, 171-8501, Tokyo, Japan

^* e-mail: yoshikazu.hirayama@kek.jp

Received: 18 October 2011
Accepted: 12 March 2012
Published online: 2 May 2012

Abstract

The tilted-foil method for producing spin-polarized radioactive isotope beams has been studied for the application to nuclear physics and materials science, using the radioactive nucleus ⁸Li ( $\ensuremath I^{\pi}=2^+$ , g = 0.82678(9) , $\ensuremath T_{1/2}=0.838(6)$ s) produced at the Tokai Radioactive Ion Accelerator Complex (TRIAC). We successfully produced polarization in a ⁸Li beam of $\ensuremath 7.3\pm0.5$ % using 15 thin polystyrene foils (4.2 $\ensuremath \mu \mathrm{g/cm}^2$ fabricated especially for this purpose. A systematic study of the nuclear polarization as a function of the number of foils, beam energy, tilt angle and foil material has been performed, confirming the features of the tilted-foil technique experimentally. The contributions made to the nuclear polarization of ⁸Li nuclei by the atomic states was investigated.