BTR code for NBI design and optimization

Abstract

BTR code (Beam Transmission with Re-ionization) is used for NBI beamlines design and studies since 2005. Initially tailored for beam re-ionized particles tracking in neutral beam ducts, BTR finally became a universal tool for 3D geometry optimization and thermal loads evaluation in injectors’ beamlines. BTR simulations include all variety of neutral beam formation and transport conditions - from the ion beam extraction grid of the ion beam source. From the very beginning BTR is created for public usage, and it comes with a truly interactive User-friendly interface (Windows GUI). The beam tracing model is straight-forward and deterministic, it is replicable and easily cross-checked with other beam tracking codes, including analytical models. BTR standard beam is a regular array of beamlets; their spatial positions, focusing and inner angular distributions are reproduced with high resolution: up to 105 test particles per beamlet. The particles are tracked in electromagnetic fields, with their transforming on gas and plasma targets, including neutralization, ionization in gas or plasma, etc. The accurate 6D (space+velocity) statistics allows a precise evaluation of beam direct losses; power deposition profiles are delivered with high resolution at the beamline components; the total amount of maps can reach several hundreds. BTR is parallel and able to trace up to 1010 macro-particles within few hours on average Windows machine, with the best performance achieved on 4-8-processor systems. Today BTR is a lively and evolving code, and free support is available to all the Users. Basic applications of BTR code are shown – with a focus on the conventional, Single-Run versions. The information on BTR upgrades and code manuals can be found online.