title: High-energy x-ray beam characterization using photonuclear reaction.
abstract: Spectral changes in the primary photon beam of a high-energy medical electron accelerator have been monitored using photonuclear reactions. The beam across the radiation field was measured using induced activity in Teflon cylinder and copper foil samples at several off-axis angles, at different SSDs in air and in a solid water phantom. The induced activities of the positron emitters were measured using a coincidence detection system. The experimental results are in agreement with Monte Carlo calculations and Schiff's theory.
authors.affiliation: Brookhaven National Laboratory, Upton, New York 11973.
authors.forename: L
authors.initials: L
authors.lastname: Wielopolski
authors.forename: X
authors.initials: X
authors.lastname: Ren
mesh_terms: D006801:Humans; D010315:Particle Accelerators; D011882:Radiotherapy, High-Energy