AFP flipper devices:: Polarized 3He spin flipper and shorter wavelength neutron flipper

We describe the development of a polarized neutron device that combines a He-3 neutron spin filter and a neutron spin flipper using adiabatic fast passage (AFP), to adiabatically reverse the He-3 polarization and thus the neutron polarization with near perfect symmetry. A typical AFP sequence takes place in 2.5-7.5ms, with the time for the He-3 transition from P to -P much less, thus the neutron polarization is nearly perfectly reversed very quickly with only a 2 x 10(-5) loss in He-3 polarization per flip. We believe this device, the He-3 flipperizer can become a standard option wherever a He-3 spin filter is already in use. Our first on beam test was performed on MIRA at the new FRM-2 reactor in Garching using polarized He-3 from HELIOS. We also briefly describe tests of a new neutron flipper based on AFP. This broad band neutron RF flipper was shown to create neutron flipping efficiencies of > 99% at a neutron wavelength of 0.4 Neutron tests were performed on D3 (ILL) and on ROTAX (ISIS). (c) 2007 Elsevier B.V. All rights reserved.