Vectorial velocity filter for ultracold neutrons based on a surface-disordered mirror system

Area of Science:

• Nuclear Physics
• Quantum Mechanics
• Materials Science

Background:

• Ultracold neutrons (UCNs) exhibit quantum mechanical properties influenced by gravity and scattering.
• Controlling UCN beams is crucial for precision measurements and fundamental physics research.
• Disorder scattering in mirror systems creates complex UCN dynamics.

Purpose of the Study:

• To investigate the potential of a mixed phase space in UCN dynamics for creating a velocity filter.
• To design and simulate an absorbing-reflecting mirror system for UCNs.
• To demonstrate the feasibility of forming low angular divergence UCN beams with controlled velocity components.

Main Methods:

• Classical three-dimensional Monte Carlo simulations were employed.
• The simulations modeled UCN scattering within an absorbing-reflecting mirror system under Earth's gravity.
• Geometric parameters of the mirror system were systematically varied.

Main Results:

• A mixed phase space of regular skipping and random motion was identified.
• The system effectively functions as a vectorial velocity filter for UCNs.
• Beams of UCNs with low angular divergence were successfully formed.
• Control over velocity components was achieved by adjusting geometric parameters.

Conclusions:

• The proposed absorbing-reflecting mirror system is a viable method for creating a UCN vectorial velocity filter.
• This technology enables the formation of controlled UCN beams for advanced experiments.
• Future applications include studying transport and scattering in confined systems.