Ultracold neutron source based on superfluid helium for the PIK Reactor

A high density ultracold neutron source based on superfluid helium is going to be created in NRC “Kurchatov Institute” — PNPI for scientific research in fundamental physics. The ultracold neutron source is to be installed on the Horizontal Experimental Channel 4 (HEC-4), which is the biggest of available experimental channels of PIK Reactor Complex. Thermal neutron flux density at the channel outlet is expected to be around 3 ×1010 cm–2s–1. The new ultracold neutron source at the PIK Reactor is planned to achieve a density of 2.2 ×103 cm–3 at ultracold neutron neutron guide exit and 200 cm–3 at neutron electric dipole moment spectrometer facility. The designed ultracold neutron guide system is going to support five experimental facilities alternately. At the initial stage the ultracold neutron source is planned to be equipped with already existing PNPI experimental plants: a neutron electric dipole moment spectrometer and neutron lifetime measuring facilities (with a gravitational and magnetic trap). A unique technological cryogenic complex with superfluid helium was designed and realized for this ultracold neutron source. Said complex includes equipment for achieving temperatures down to 1 K and removal of up to 60 W of heat from superfluid helium.