Development of a quadrupole magnet to polarize cold neutrons for SANS experiments

Oku, Takayuki   ; Suzuki, Junichi; Kira, Hiroshi; Shinohara, Takenao   ; Takata, Shinichi  ; Arai, Masatoshi; Hirota, Katsuya*; Iwashita, Yoshihisa*; Shimizu, Hirohiko*

Spin selective neutron transportation and beam shaping can be realized based on the interaction between the neutron magnetic moment and magnetic field. The magnetic optics for neutrons is flexible optics since we can control its characteristics by changing the multiplicity of magnetic poles. So far, we have constructed the polarized neutron focusing system consisting of the quadrupole and sextupole magnets, and successfully introduced it into the SANS instrument. The quadrupole has a small aperture of 5 mm in diameter. Because of its small aperture, the application of the quadrupole magnet is limited in sans experiments with focusing geometry for high angular resolution. Therefore, we have developed a quadrupole magnet with a larger aperture of 15 mm in diameter and longer magnet length of 2200 mm. In this paper, we described the specifications of the new quadrupole magnet and discuss about its application in polarized neutron scattering.