ILL sets ultra-cool neutron science record

BBC : Although neutrons were discovered 79 years ago, some of their basic properties have been difficult to measure precisely. One trick to gain better precision is to create a large number of ultracold, or very slow-moving, neutrons to study. With a refined version of an approach they developed in 2007 , Oliver Zimmer of the Institut Laue Langevin (ILL) in Grenoble, France, and colleagues used superfluid helium-4 at a frigid four degrees above absolute zero to trap neutrons at a density of 55 per cubic centimeter. That breaks the previous density record, which was also set at the ILL. Zimmer believes the new approach could bring the neutron density to 1000 per cubic centimeter, which would serve to increase the statistical precision of experiments and help exclude theories beyond the standard model.