The construction of a neutron depolarization beamline at W3 port in the Tsing-Hua Open Pool Reactor

• Main Authors: Chih-Wei Hu, 胡芝瑋
• Other Authors: Chih-Hao Lee
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/56500920786110257198

碩士 === 國立清華大學 === 工程與系統科學系 === 94 === The purpose of this thesis is to construct a neutron depolarization (ND) beamline in the Tsing-Hua Open Pool Reactor (THOR) in order to measure the magnetic characteristics in the interior of magnetic materials. The ND experiments were carried out at W3 port of THOR (2 MW). The neutron beam with wavelength λ0 = 2.37 Å is chosen by graphite monochromator, and then polarized and analyzed by Heusler Cu2MnAl (111) crystals. The neutron polarization ratio of the beamline is about 82%. The depolarized neutrons were collected by a 3He detector. Four hundred neutron counts per second was achieved. A Ni75Fe25 sample was used to test the performance of this beamline. The measured depolarization factor is 0.789 and the procession angle is 2.61 rad, which imply the mean magnetic domain size is 34±7 μm and mean magnetic induction is 236.6 Oe has been investigated by ND technique in Ni75Fe25.