INTENSITY: a computer program for the estimation of secondary beam intensities from a projectile fragment separator

Abstract

Radioactive ion beams are rapidly becoming an important new tool in nuclear science research. A number of facilities have been built or are under construction worldwide which will allow separation of relatively pure radioactive ion beams. A number of these facilities, including LISE at GANIL, RIPS at RIKEN, the FRS at GSI, and the A1200 at the NSCL, are based on the separation of projectile-like fragments using a doubly achromatic system. As part of the work leading up to experiments using the A1200, we have developed a computer code which allows fast, interactive estimation of secondary ion beam intensities and purities for use in the design and interpretation of experiments. The code has been designed to model and doubly achromatic device of design similar to the A1200 by using an idealized initial secondary beam from a production target. The various atomic effects involving the interaction of ion beams with targets and degraders, including the equilibrium charge states of beams leaving these materials, have been analyzed in detail and incorporated into the program. An analytical description of the beam transport system using first order beam optics has been developed. A comparison between the program and various other simulation methods as well as measured production rates have shown good agreement.