  To explore the limits of layer wound (RE)Ba2Cu3O7-x (REBCO, RE = Rare Earth)
coils in a high magnetic field environment > 30 T, a series of small insert
coils have been built and characterized in background fields. One of the coils
repeatedly reached 35.4 T using a single ~100 m length of REBCO tape wet wound
with epoxy and nested in a 31 T background magnet. The coil was quenched safely
several times without degradation. Contributing to the success of this coil was
the introduction of a thin polyester film that surrounded the conductor. This
approach introduces a weak circumferential plane in the coil pack that prevents
conductor delamination that has caused degradation of several epoxy impregnated
coils previously made by this and other groups.
