Miniaturized time-of-flight neutron spin flipper using a high-TCsuperconductor

A miniaturized neutron spin flipper based on a high-TCsuperconductor film, developed at the China Spallation Neutron Source (CSNS), is presented. A neutron spin flipper is an essential component for performing polarized neutron experiments and, as such, constitutes a high priority for developing CSNS’s polarized neutron capability. To provide the beamlines with a universal neutron spin flipper operating over a wide wavelength band, the neutron spin flipper utilizes non-adiabatic spin flipping during transit through opposite magnetic fields that are mutually shielded by the superconductor Meissner effect. A compact vacuum heat shield and a low-power consumption sterling refrigerator maintained the superconducting condition while reducing the size and power input of the flipper. The prototype device was tested at the CSNS BL-20, which demonstrated a flipping efficiency of 99% at 4 Å.