Half-section view of a magnetic neutron trapping apparatus. A beam of cold neutrons passes through a series of teflon windows and enters a bath of helium from the left. Some of the neutrons scatter from the helium atoms. Those neutrons (yellow) in a low-field-seeking spin state and with energy below the trap depth are magnetically confined. The trapping field is created by assembly of superconducting magnets.
reported by: Huffman et al., in the 6 January Nature