ACHRO: A program to help design achromatic bends Available to Purchase

ACHRO is a very simple 2000‐line FORTRAN code that provides help for the designer of the achromatic bend. Given a beam momentum, the program calculates the required drift lengths and dipole parameters which it will apply to any one of several different types of achromats. The types of achromats that the code helps to design include the Enge Dual‐270°, the Brown 2‐Dipole, the Leboutet 3‐Dipole, and the Enge 4‐Dipole, as well as the nonsymmetric and stair‐step varieties. Given the dimensions into which a bend must fit, ACHRO will calculate the geometrical parameters in an Z‐X plane for a single or multiple achromat, and for achromatic ‘‘S‐bend’’ configurations where possible. ACHRO makes it very easy to optimize a bend with respect to drift lengths and magnet parameters by allowing the user to change parameter values and see the resulting calculation. Used in conjunction with a beam‐transport code, the designer can consider various types of achromatic bends in the same beamline layout in order to compare important bend characteristics such as dispersion at nonachromatic points, isochronicity, sensitivity to errors, geometric or chromatic aberrations, aperture requirements, space for diagnostics, etc., all of which are largely a function of the geometry and the type of achromat selected.