Decomposition of the absorbed dose by LET in tissue-equivalent materials within the SHIELD-HIT transport code

The SHIELD-HIT transport code, in several versions, has been used for modeling the interaction of therapeutic beams of light nuclei with tissue-equivalent materials for a long time. All versions of the code include the useful option of decomposition of the absorbed dose by the linear energy transfer (LET), but this option has not been described and published to date. In this work the procedure of decomposition of the absorbed dose by LET is described and illustrated by using the decomposition of the Bragg curve in a water phantom, irradiated by beams of protons, alpha particles, and ions of lithium and carbon.