Uniform beam distributions at the target of the NASA Space Radiation Laboratory’s beam line

Errors in delivering a uniformly distributed radiation dose to biological and material samples exposed to charged particle beams are a significant problem for experimenters. In this paper, we discuss data collected on the uniform beam distributions produced for NASA's Space Radiation Laboratory (NSRL) at Brookhaven National Laboratory (BNL), using a method that was conceived theoretically and tested experimentally at BNL. This method [N. Tsoupas et al., Nucl. Sci. Eng. 126, 71 ( 1997)] of generating uniform beam distributions on a plane normal to the beam's direction relies only on magnetically focusing the transported beam; no collimation of the beam is required or any other type of interaction of the beam with materials other than the target material. The method compares favorably with alternative methods of producing such distributions, and it can be applied to the entire energy spectrum of charged particle beams that are delivered to the NSRL's experiments by the Booster for the Alternating Gradient Synchrotron at BNL.