Measurement of spin-flip probabilities for ultracold neutrons interacting with nickel phosphorus coated surfaces

الأصل · EN

We report a measurement of the spin-flip probabilities for ultracold neutrons interacting with surfaces coated with nickel phosphorus. For 50 μm thick nickel phosphorus coated on stainless steel, the spin-flip probability per bounce was found to be β NiPonSS = (3.3⁺¹.⁸₋₅.₆) × 10⁻⁶. For 50 μm thick nickel phosphorus coated on aluminum, the spin-flip probability per bounce was found to be β NiPonAl = (3.6⁺².¹₋₅.₉) × 10⁻⁶. For the copper guide used as reference, the spin flip probability per bounce was found to be β Cu = (6.7⁺⁵.⁰₋₂.₅) × 10⁻⁶. The results on the nickel phosphorus-coated surfaces may be interpreted as upper limits, yielding β NiPonSS < 6.2 × 10⁻⁶ (90% C.L.) and β NiPonAl < 7.0 × 10⁻⁶ (90% C.L.) for 50 μm thick nickel phosphorus coated on stainless steel and 50 μm thick nickel phosphorus coated on aluminum, respectively. Nickel phosphorus coated stainless steel or aluminum provides a solution when low-cost, mechanically robust, and non-depolarizing UCN guides with a high-Fermi-potential are needed.