The Capture Cross Section of Thermal Neutrons in Water

Opportunistic dose amplification for proton and carbon ion therapy via capture of internally generated thermal neutrons

“…Light water, the principal constituent of human tissue, has a moderate thermal neutron cross-section (0.335 barns 12 ), which can be greatly increased by the introduction of agents containing isotopes such as 10 B or 157 Gd with very high neutron cross sections (3838 and 254000 barns, respectively 13 , 14 ). While nonelastic thermal neutron interactions with water primarily result in hydrogen capture of the neutron and the release of a high-energy gamma photon, nonelastic thermal neutron interactions with 10 B and 157 Gd result in the production of energetic charged particles with high relative biological effectiveness - the basic operating principle of neutron capture therapy (NCT) 15 , 16 .…”

Measurements of Neutron Thermalization Parameters in Light Water by Pulsed Source and Non 1/vAbsorber Method

“…ll to the analysis of the experimental data, the assumption, I D(E) p,o (E, t; rolma (E) I ~1, must be confirmed for this measuring system. To this end, the decay constants of neutron density in pure water were measured 205 for several positions of the detector, and compared with the values of ~aovo obtained from the ordinary pulsed experiment<' 6 ) and with those from measurements of diffusion length in a non-stationary neutron field<' 7 ).…”

Study of a Halpern-type 4 [pi] neutron detector.

“…A discriminator was set to fire when this The relative neutron counter efficiencies for the P(y,n) P source are plotted versus peak bremsstrahlung energy in Fig. 16 This effect has been observed before [20] . •O These effects were the greatest when B was in the plane determined by A and the source.…”