Specifics of preparation of storage chambers for ultracold neutrons and EDM spectrometer sensitivity

Storage cells for ultracold neutrons (UCNs) are crucial parts of the experimental setup used to measure the electric dipole moment (EDM) of a neutron. The effect of the technology of preparation and sputtering of elements of UCN storage cells on the limiting operating voltage and on the capacity of these cells for long-term operation under high voltage with polarity switching was studied. A voltage magnitude of $\pm$ 250 kV was obtained in tests of a neutron storage cell for the EDM spectrometer with a cell height of 9 cm.