A WHITE-BEAM NEUTRON SPIN SPLITTER

The polarization of a narrow, highly collimated polychromatic neutron beam is tested by a neutron spin splitter that permits the simultaneou s measurement of both spin states. The device consists of a Si-Co0.11F e0.89 supermirror, which totally reflects one spin state up to a momen tum transfer q = 0.04 Angstrom(-1), whilst transmits neutrons of the o pposite spin state. The supermirror is sandwiched between two thick si licon wafers and is magnetically saturated by a magnetic field of 400 Oe parallel to its surface. The neutron beam enters through the edge o f one of the two silicon wafers, its spin components are split by the supermirror and exit from the opposite edges of the two silicon wafers and are recorded at different channels of a position-sensitive detect or. The device is shown to have excellent efficiency over a bread rang e of wavelengths. (C) 1998 Published by Elsevier Science B.V.