%0 Journal Article
%A
%A
%T The scattering of slow neutrons by *ortho*- and *para*-hydrogen
%D 1955
%R 10.1098/rspa.1955.0110
%J Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences
%P 19-32
%V 230
%N 1180
%X The neutron velocity selector of the Cavendish Laboratory has been used to measure the scattering cross-sections of ortho- and para-hydrogen for slow neutrons. The triplet and singlet scattering amplitudes of the neutron-proton interaction may be deduced from these cross-sections. The values obtained are at = (0·537 ± 0·004) x 10-12 cm, as = -(2·373 ±0·007) x 10-12 cm, where at and as are the triplet and singlet scattering amplitudes respectively. The values of the coherent scattering amplitude ƒ = 2(3/4a+1/4a), and of the free proton cross-section σƒ= 4π(3/4a2t + 1/4a2s given by the above values of at and as, are ƒ = -(0·380 ± 0·005) x 10-12 cm, σƒ= (20·41 ± 0·14) x 10-24 cm2.
%U http://rspa.royalsocietypublishing.org/content/royprsa/230/1180/19.full.pdf