radiation dosimetry model EFFTRAN https://efftran.github.io/ Paul Schofield EFFTRAN is a Monte Carlo efficiency transfer code for gamma-ray spectrometry, developed at SCK-CEN, that enables calculation of detection efficiencies for arbitrary source geometries by transferring reference efficiencies measured with point sources or standard geometries to other geometries. It supports accurate activity measurements in environmental, waste and biological samples with non-standard geometries without requiring separate calibration measurements. The software is available from the author upon request and usage should be cited. Located at SCK.CEN, Belgian Nuclear Research Centre. Tim Vidmar, 2005, Nuclear Instruments and Methods in Physics Research A 550, 603-608