Seismic noise in crystal neutron interferometry

We are involved in designing, constructing and operating a split-crystal interferometer that uses X-rays and neutrons simultaneously. Neutron interferometers are sensitive to seismic and acoustic noise due to the low speed, low flux and long detection time of thermal neutrons. The crystal splitting and the increased length and separation of the interferometer arms further heighten this sensitivity. To support the interferometer design and operation, we present an estimate of the root-mean-square phase noise when the interferometer is passively isolated from ground accelerations.