Detailed Transfer Line Beam Characteristics at an Operational Proton Therapy Center

<ns3:p>The McLaren Proton Therapy Center functions as a multi-room, clinically active cancer treatment center. Beam position, size, and current measurements along the transfer lines have been utilized together with simulations to validate computer models for the Center’s transfer lines and associated beam parameters. Beam profile monitor (BPM) data collected along the beamlines provided detailed beam measurements. A computer tool, utilizing nonlinear constrained optimization programs that are integrated with a beam envelope code, was used to find detailed beam phase space parameters (centroids, sigma matrices) that reproduced the measured data. Quadrupole scan and steerer scan experiments have been used to validate the calibration and alignment of these devices, as well as to independently confirm beam parameters at selected locations. Beam current measurements along the beamlines were used to infer transmission efficiencies and then compared to multi-particle simulations in order to identify beam loss locations. The work resulted in an improved understanding of the beams and beam transfer lines to support further beamline optimization and design activities. The experimental and simulation methodologies, tools, and results and their interpretations should be applicable to many types of operating accelerator facilities.</ns3:p>