Photoneutron yields from tungsten in the energy range of the giant dipole resonance

Abstract

Photoneutron production on the nuclei of high-Z components of medical accelerator heads can lead to a significant secondary dose during a course of bremsstrahlung radiotherapy. However, a quantitative evaluation of secondary neutron dose requires improved data on the photoreaction yields. These have been measured as a function of photon energy, neutron energy and neutron angle for natW, using tagged photons at the MAX-Lab photonuclear facility in Sweden. This work presents neutron yields for natW(gamma, n) and compares these with the predictions of the Monte Carlo code MCNP-GN, developed specifically to simulate photoneutron production at medical accelerators.

An Artificial Neural Network-Based Estimation of Bremsstarahlung Photon Flux Calculated by MCNPX

“…The capabilities of MCNPX have been investigated in literature. Various applications using MCNPX code have been found in literature [14][15][16][17][18][19].…”

Monte Carlo Simulation of Photoneutron Dose in Radiotherapy Room as A Function of Gantry Angles

“…A significant number of neutrons are generated via (γ,n) reaction. Those photoneutron contamination comes from the target, the filter, the collimator and any places struck by high energy X-rays [4][5][6][7][8][9]. Besides the known effects of radiation, the effects of surgical operations are still largely unknown.…”

Radiotherapy dose enhancement using BNCT in conventional LINACs high-energy treatment: Simulation and experiment

“…The production is governed by Giant Dipole Resonance reaction (GDR), and neutrons are generated when the incident photon energy exceeds the GDR reaction threshold (6-20 MeV). 6 The nuclear photon absorption cross section, as a function of photon energy E, is described by the Levinger and Bethe formula, 7 in which cross section is proportional to the atomic number Z of the nuclide considered. Depending on the atomic number Z of the target nucleus, it is thus possible to distinguish two main cases: GDR threshold energy 8 (E GDR , Th ) of about 7-8 MeV for high-Z materials (Z > 20, such as Pb, W, Cu, Fe) that compose LINACs head and collimators, and E GDR , Th of about 16-18 MeV for low-Z ones (Z < 20 such as P, Ca, O, C) that constitute human body.…”