Measurement of coherent neutron scattering lengths of gases

With the neutron interferometer, measurements of the coherent neutron scattering lengths by various gases have been performed. We get the following numbers for the bound coherent scattering lengths for atoms (in fm):b _c (H) =?3.64(3),b _c (D)=6.55(8),b _c (He?3)=5.74(7),b _c (He)=3.26(3),b _c (N)=9.30(8),b _c (O)=5.83(5),b _c (Ne) =4.63(4),b _c (Ar)=2.07(2),b _c (Kr)=7.52(6),b _c (Xe)=4.69(4). In some cases greater accuracy is achieved in comparison with recommended values from the literature. The absolute values for hydrogen and deuterium measured with gaseous samples, are about 2% smaller than the values measured with liquids and other reference values.