[en] The present review is focused on the problem of interaction of neutron waves with moving matter. The validity of the 1/ v law for ultracold neutrons and the possibility to characterize the interaction of neutrons with matter using the effective potential were verified in the so-called null Fizeau experiments. A neutron wave in such experiments propagates through a flat sample that moves parallel to its edges. The observation of effects caused by this motion provides evidence that the concept of constant effective potential is not correct. The second part of the review deals with the prediction and the first observation of the accelerated matter effect (a change in the energy of neutrons in passing through a refractive sample that moves with an acceleration directed along or opposite the direction of neutron propagation). The characteristic features of this phenomenon in the case of birefringent material are considered. In conclusion, the problem of propagation of neutron waves in matter moving with giant acceleration is discussed.

[en] Experimental and theoretical studies in the physics of ultracold neutrons are reviewed. Experimental methods and the interaction of ultracold neutrons with matter and fields are discussed. Possible applications of ultracold neutrons are considered

[en] Ultra cold neutrons from a polyethylene converter located in the thermal column of the NRU reactor have been transmitted along a highly polished copper tube of length 5.3 m. The measured intensity and its variation with gas pressure in the tube indicate that the reflections are almost 100 % specular. The yield of the ultra cold neutrons increases by a factor of 3 as the polyethylene is cooled from 40 deg C to -170 deg C. (author)

[en] The ILL method for measuring neutron lifetime using ultracold neutrons bottled in an evacuated container is described

[en] A superthermal Ultra-Cold Neutron source containing a dilute solution of polarized ₃He in ₄He can provide a method for carrying out the search for the neutron electric dipole moment which not place any limits on the solid angle of the incoming neutrons and eliminate losses due to several causes

[en] The parameters of a neutron interferometer using diffraction gratings for very cold neutrons (νapprox.=17 m/s and less) are analyzed. A symmetrical scheme of the neutron interferometer is proposed, with the phase reflection gratings arranged horizontally, which permits a good spatial separation of the beams (up to 50 cm) and a high intensity of the neutron beam at the interferometer exit. (orig.)

No abstract available

No abstract available

[en] In experiments on multiple reflection of ultracold neutrons from plane parallel glass surfaces the coefficient of their mirror reflection eta is determined. The obtained value eta=(98.6+-0.1)% agrees well with these estimated by other authors

[en] We present a brief introduction to the field of Ultran-Cold neutron (UNC) research including a review of the properties of UCN and some current and future applications. We then discuss two types of UCN source suitable for use in connection with spallation neutron sources - Doppler shifter and Superthermal UCN sources. (orig.)