Large Area Proton Beams for Radiobiologic Research from the Nasa-Srel Synchrocyclotron. I. Investigation of the Nominal 300-Mev Primary Beam. Ii. Investigation of the Nominal 600-Mev Primary Beam

摘要

Measurements have been made of the characteristics of large area proton beams for radiobiologic research from the 600-Mev synchrocyclotron. Proton beams with energies ranging from 450 to 150 Mev were produced by degrading the nominal 600-Mev primary beam to the desired energy with the appropriate thickness of aluminum, copper, or lead at the beam transport system exit port. Proton beams with energies ranging from 295 to 30 Mev were produced by degrading the nominal 300-Mev beam from the synchrocyclotron. In addition, the primary beams were expanded with the quadrupole magnets of the beam transport system, and the characteristics of these beams were investigated. The maximum proton flux and spatial distribution of the flux of the various beam configurations were measured at distances of 5, 10, and 15 feet from the exit port, and the corresponding dose rates in tissue were calculated from the maximum flux values. The intensity profiles of the degraded beams were found to be approximately Gaussian, and measurements of several such profiles indicated that the beams were approximately circular. The profile widths and dose rates were measured for many different configurations. (Author)