A senior researcher at the Laboratory of Nuclear Problems at JINR Sergey Dolya proposed an effective way to cool the neutron flux to ultra-low temperatures. The new patented technology opens wide opportunities for particle physics research.

The developed neutron cooling method, based on the law of reflection for a moving mirror, allows reaching temperatures below 2 millikelvin (mK°). It will allow researchers to carry out high-precision measurements of the lifetime and properties of neutrons. This will make a significant contribution to particle beam control. The obtained data can be used to calculate the coupling constant of weak interactions, which is important for research in not only particle physics, but also in astrophysics and cosmology.

The formula of the invention:

1. The method for cooling the neutron flux includes reflecting neutrons from a periodically inhomogeneous medium (reflector) and keeping them in a gravitational trap, with the neutron velocities parallel to the normal to the reflector. Its characteristic feature is that the neutron are cooled using a reflector, which is a travelling wave of the second sound in liquid helium II with λ s period two times shorter than the wavelength of the λ n neutrons and the difference between the velocities of the neutrons and the doubled velocity of the reflector less than the boundary velocity at which the neutrons are still trapped in the gravitational trap, while the direction of movement of the reflector coincides with the direction of movement of the neutrons.

2. The device for implementing the neutron flux cooling method includes a reflector with a periodically inhomogeneous medium, which has the ability to move, and a gravitational trap. Its characteristic features are a container with liquid helium II, a periscope system for introducing neutrons into the container, and a travelling wave emitter of the second sound located below the surface of liquid helium II; in this case, the reflector It is a travelling wave of the second sound in liquid helium II with a uniform spatial period. It can only move in the direction of the neutron velocity.

The Joint Institute for Nuclear Research obtained patent RU 2828765 for the invention entitled “A neutron flux cooling method and a device for its implementation” on 17 October 2024.

Congratulations to Sergey N. Dolya on receiving the state registration!