D. Kustov

New gravitational experiment with ultracold neutrons

The results of a new neutron gravitation experiment are reported. The change in the energy of a neutron falling to a known height in the Earth’s gravitational field is compensated by an energy quantum ħΘ transferred to the neutron as a result of the phase modulation of the neutron wave. A phase diffraction grating moving across the direction of the propagation of the neutron wave is used as a modulator. The experiment has been carried out with ultracold neutrons Interference filters, neutron analogues of Fabry-Perot interferometers, are used for the spectrometry of ultracold neutrons. The force mggn acting on the neutron in the Earth’s gravitational field has been measured with an accuracy of about 0.2%.

Effect of accelerating matter in neutron optics

The results of an experiment on the observation of a new neutron-optical effect are reported. It has been experimentally shown that the energy of a neutron passing through a refracting sample moving with acceleration changes. The magnitude of the effect is in qualitative agreement with theoretical predictions. The experiment was carried out with ultracold neutrons and the energy transform is equal to ±2 × 10−10 eV.

Neutron Diffraction at a Moving Grating as a Nonstationary Quantum Phenomenon

The observation of the discrete energy spectrum in a new experiment on the diffraction of ultracold neutrons at a moving phase grating is reported. The results are in quantitative agreement with theoretical predictions and can be treated as additional evidence of the validity of the plane-wave representation of the initial neutron state.

Spectrometer for new gravitational experiment with UCN

Abstract We describe an experimental installation for a new test of the weak equivalence principle for neutron. The device is a sensitive gravitational spectrometer for ultracold neutrons allowing to precisely compare the gain in kinetic energy of free falling neutrons to quanta of energy ℏ Ω transferred to the neutron via a non stationary device, i.e. a quantum modulator. The results of first test experiments indicate a collection rate allowing measurements of the factor of equivalence γ with a statistical uncertainty in the order of 5×10 −3 per day. A number of systematic effects were found, which partially can be easily corrected. For the elimination of others more detailed investigations and analysis are needed. Some possibilities to improve the device are also discussed.

Accelerating medium effect as a general wave phenomenon

Already at the end of the last century theory predicted that the wave number and frequency of any wave will change when passing an accelerating refractive medium. The effect was calculated both for electromagnetic and neutron waves. As a refractive index may be introduced for waves of any nature one can speak about a very general Accelerating Medium Effect. As far as we know this effect has not yet been observed for light. Here we report on a neutron-optics experiments performed with ultra-cold neutrons where this effect has been demonstrated for the first time ever. The maximum energy transform in the experiment was ± (2÷6) ×10−10 eV which agrees with theory within less than 10%. Possibilities for future investigations of the Accelerating Medium effect will be discussed.

Experiment proposed for the observation of UCN interaction with matter moving with giant acceleration

It was assumed that in neutron optics the concept of the effective potential has a limited region of validity, which is unlikely in the case of giant acceleration of matter. In the current work an experimental approach to test this hypothesis has been proposed.