Ultra-Sensitive Depolarization Study of Polarizing CoTi Supermirrors with the Opaque Test Bench

We have investigated the depolarization of neutrons in the reflection on polarizing supermirrors, using the opaque test bench. It consists of two opaque 3He cells with in-situ adiabatic fast passage flipping of the helium spin. In a beam initially polarized to AP = 99.98%, depolarization of the order of 10−2 is evidenced after a single reflection on a polarizing supermirror. Depolarization could be reduced though not completely suppressed when working at high magnetizing fields (0.82 T). The preliminary data analysis also suggests a correlation between the m-value of the supermirror and depolarization.