New source for ultracold neutrons at the Institut Laue-Langevin

摘要

A new intense superthermal source for ultracold neutrons (UCN) has beeninstalled at a dedicated beam line at the Institut Laue-Langevin. Incidentneutrons with a wavelength of 0.89 nm are converted to UCN in a five litervolume filled with superfluid $^4$He at a temperature of about 0.7 K. The UCNcan be extracted to room temperature experiments. We present the cryogenicsetup of the source, a characterization of the cold neutron beam, and UCNproduction measurements, where a UCN density in the production volume of atleast 55 per cm$^3$ was determined.