Longitudinal-gradient magnet for time focusing of ultra-cold neutrons

Y. Arimoto, T. Yoshioka, H. M. Shimizu, K. Mishima, T. Ino, K. Taketani, S. Muto, M. Kitaguchi, S. Imajo, Y. Iwashita, S. Yamashita, Y. Kamiya, A. Yoshimi, K. Asahi, T. Shima, K. Sakai

Research output: Contribution to journalConference articlepeer-review

8 Citations (Scopus)


A gradient DC magnet is designed using 3D magnetic field analysis code. This magnet, referred to as a B0 magnet, is one of the key elements of a time-focusing device for ultra-cold neutrons (UCNs) based on a radio frequency gradient flipper - a so-called rebuncher. The magnet generates a guide and a potential field that interacts with the magnetic moment of UCNs and its main body comprises a C-shaped yoke made from iron. A field gradient is generated by a pole arrangement that includes an anisotropic inter-pole, which causes the fringe field to be uniform in the longitudinal direction even when the pole gap distance changes. The designed magnet has the following properties: (1) a maximum B-field of 10 kGauss, decreasing to 2 kGauss at a longitudinal distance of 25 cm, with a gradient of less than 400 Gauss/cm, (2) variations in the fringe field along the y direction is less than 4% over a range of -3 cm≤ y ≤ 3 cm at any z position in the spin-flipping region. Tracking simulations show that the B0 magnet is capable of accepting UCNs in the velocity range 2.3∼3.3 m/s.

Original languageEnglish
Pages (from-to)20-29
Number of pages10
JournalPhysics Procedia
Publication statusPublished - 2011
Externally publishedYes
Event2nd International Workshop on the Physics of Fundamental Symmetries and Interactions, PSI 2010 - Villigen, Switzerland
Duration: Oct 11 2010Oct 14 2010

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy


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