Beam transport line of CIAE medical cyclotron and its magnetic elements design studies

摘要

More than 300 /spl mu/A proton beam has to be transported from exit of a cyclotron to target. The final beam spot less than /spl Phi/8 mm in diameter was asked. To reduce the cost of the system the beam aperture is limited to 50 mm in diameter and the magnetic elements are carefully designed with easier fabrication and loose tolerance. For example, the cross section of the pole faces of the quadrupoles are broken line shaped instead of hyperbola. And the two steering magnets have been added to control the vertical and horizontal position of the beam on the target.