title: Compact spherical neutron polarimeter using high-T(c) YBCO films.
abstract: We describe a simple, compact device for spherical neutron polarimetry measurements at small neutron scattering angles. The device consists of a sample chamber with very low (<0.01 G) magnetic field flanked by regions within which the neutron polarization can be manipulated in a controlled manner. This allows any selected initial and final polarization direction of the neutrons to be obtained. We have constructed a prototype device using high-T(c) superconducting films and mu-metal to isolate regions with different magnetic fields and tested device performance in transmission geometry. Finite-element methods were used to simulate the device's field profile and these have been verified by experiment using a small solenoid as a test sample. Measurements are reported using both monochromatic and polychromatic neutron sources. The results show that the device is capable of extracting sample information and distinguishing small angular variations of the sample magnetic field. As a more realistic test, we present results on the characterization of a 10 μm thick Permalloy film in zero magnetic field, as well as its response to an external magnetic field.
authors.affiliation: Center for Exploration of Energy and Matter, Indiana University Bloomington, Bloomington, Indiana 47408, USA.
authors.forename: T
authors.initials: T
authors.lastname: Wang
authors.affiliation: Center for Exploration of Energy and Matter, Indiana University Bloomington, Bloomington, Indiana 47408, USA.
authors.forename: S R
authors.initials: SR
authors.lastname: Parnell
authors.affiliation: Neutron Science Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37381, USA.
authors.forename: W A
authors.initials: WA
authors.lastname: Hamilton
authors.affiliation: Center for Exploration of Energy and Matter, Indiana University Bloomington, Bloomington, Indiana 47408, USA.
authors.forename: F
authors.initials: F
authors.lastname: Li
authors.affiliation: Department of Physics and Astronomy, The University of Sheffield, Sheffield S10 2TN, United Kingdom.
authors.forename: A L
authors.initials: AL
authors.lastname: Washington
authors.affiliation: Center for Exploration of Energy and Matter, Indiana University Bloomington, Bloomington, Indiana 47408, USA.
authors.forename: D V
authors.initials: DV
authors.lastname: Baxter
authors.affiliation: Center for Exploration of Energy and Matter, Indiana University Bloomington, Bloomington, Indiana 47408, USA.
authors.forename: R
authors.initials: R
authors.lastname: Pynn