Stripping-theory analysis of thick-target neutron production for D+Be (and tissue dose calculation)

• Published in: Physics in medicine & biology 1976-11, Vol.21 (6), p.931-940
• Main Authors: August, L S, Attix, F H, Herling, G H, Shapiro, P, Theus, R B
• Format: Article
• Language: English
• Subjects: Beryllium; Deuterium; Fast Neutrons - therapeutic use; Models, Theoretical; Neutrons - therapeutic use; Physical Phenomena; Physics
• ISSN: 0031-9155; 1361-6560
• DOI: 10.1088/0031-9155/21/6/003

The Serber theory for deuteron stripping is employed to predict the shape of the neutron energy spectrum produced by 35 MeV deuterons (D+) on a thick beryllium target. In particular, the observation that the maximum of the neutron energy spectrum (at 0degrees relative to the deuteron beam direction) occurs at approximately 0-4Ed, where Ed is the incident deuteron energy, is explained reasonably well by the calculations. The explanation stems mainly from the fact that the stripping theory for thin targets predicts a narrow maximum at 0-5Ed, and thick target effects shift the maximum downward in energy to approximately 0-4Ed. A number of recent spectral measurements are in agreement with these predictions for a wide range of target materials and incident deuteron energies. The application of this theory also accounts for the previously observed Dd2-99 dependence of the absorbed dose in tissue,per unit charge of D+ ions on target, in the direction of the incident beam. This approximate Ed3 dependence is shown to be a characteristic property of deuteron stripping in a thick target and follows directly from the calculations that predict the neutron energy spectrum.