Simulations, analysis, and measurements are performed on the BNL Booster’s third integer resonance extraction to the NSRL line, which uses a constant optics slow extraction method. In this method, ring dipoles and quadrupoles are changed synchronously for a coasting beam, which aids in maintaining a fixed separatrix orientation through the spill. Simulations show that the outgoing beam has a very small dispersion, independent of the periodic dispersion value at the septum. We show using a first-order normal form approximation that transforms to the Kobayashi Hamiltonian, how the dynamics of such a spill lead to a dispersion-free outgoing beam, which is critical to the uniformity requirements of the NSRL. Finally, we measure the dispersion of the beam by varying the flattop energy of the coasting beam in the booster before engaging the spill and show that the magnitude of dispersion is reduced by over a factor of 5 from the periodic value in the ring.

This paper describes the foil structure used at the beam extraction point in the NASA Space Radiation Laboratory (NSRL) beamline. The stripping foil removes electrons from incoming ions, rendering them partially or fully stripped. Foils of various materials and thicknesses are employed, enabling ion species at different energies to pass through. As charged particles traverse a foil, the outgoing particles exhibit a Gaussian-like angular distribution. This distribution is subsequently transformed into a uniform profile by a set of octupole magnets, essential for various beam experiments at the NSRL target. We utilize the Bmad and SRIM computer codes to calculate the energy loss through the foils for different ion species, energies, and charge states. After preparing ion beam species in the Booster, we determine the energy loss by measuring the horizontal beam profile at the multi-wire MW063 location in the NSRL beamline. Finally, we present a summary of energy loss calculations obtained through Bmad, SRIM, and experimental data.

Simulations, analysis, and measurements are performed on the BNL Booster’s third integer resonance extraction to the NSRL line, which uses a constant optics slow extraction method. In this method, ring dipoles and quadrupoles are changed synchronously for a coasting beam, which aids in maintaining a fixed separatrix orientation through the spill. Simulations show that the outgoing beam has a very small dispersion, independent of the periodic dispersion value at the septum. We show using a first-order normal form approximation that transforms to the Kobayashi Hamiltonian, how the dynamics of such a spill lead to a dispersion-free outgoing beam, which is critical to the uniformity requirements of the NSRL. Finally, we measure the dispersion of the beam by varying the flattop energy of the coasting beam in the booster before engaging the spill and show that the magnitude of dispersion is reduced by over a factor of 5 from the periodic value in the ring.