Possibility for low temperature fluid-wall neutron bottle with very low neutron upscattering losses

The new recently synthesized polymers – perfluorinated polyformaldehydes have long liquid range and low melting point. Due to the expected low upscattering losses of ultracold neutrons, at low temperatures, these fluids may be good candidates for precision measurement of neutron lifetime by the method of storage of ultracold neutrons in traps.