Numerical Calculation of Electric Field Enhancement in Neutron Traps with Rough Walls Coated with Superfluid Helium

TL;DR

This paper models the electric field distribution near rough trap walls coated with superfluid helium, assessing its role in maintaining helium films for ultracold neutron confinement.

Contribution

It introduces a numerical method to calculate electric field enhancement near rough surfaces coated with superfluid helium in neutron traps.

Findings

Electric field concentrates at surface roughness tips.

Field distribution influences helium film stability.

Numerical results support trap design improvements.

Abstract

A film of liquid helium on the surface of material traps for ultracold neutrons protects the neutrons from being absorbed by the trap walls. By using surface roughness and an electrostatic field, it is possible to maintain a helium film of sufficient thickness throughout the height of the trap. The field distribution near the tip of such wall roughness of the trap was calculated, and the effect of this field on holding the helium film was estimated.