This is a Python package for the quantitative analysis of the interaction of energetic x-rays with matter. This package is named after one of the discoverers of X-rays, Wilhelm Roentgen. He was awarded the very first Nobel Prize in Physics “in recognition of the extraordinary services he has rendered by the discovery of the remarkable rays subsequently named after him”. X-rays were originally referred to as Roentgen rays.

The scope of this package is evolving but it currently includes the penetration or absorption of x-rays in materials. These materials may be metals, gases, biological, or detector materials. It also includes the generation of x-rays from emission lines.