Gavin Poludniowski (PhD) is a radiation physicist and recognized expert on modelling x-ray tubes. He has been instrumental in the development of spectrum software such as SpekCalc and SpekPy that are used in hospitals, industry, and research institutions around the world. Artur Omar (PhD) is a medical physicist whose research has involved modelling bremsstrahlung and characteristic x-ray production, estimating patient radiation dose and occupational dosimetry. His doctoral work pioneered the development of a more sophisticated analytical model of the x-ray spectrum. Prof. Pedro Andreo (PhD, DSc, CPhys, FInstP) is a leading scientist in radiation dosimetry and Monte Carlo calculations, having more than 350 publications and conference contributions. He has co-authored most of the existing national and international recommendations for reference dosimetry and received a number of international awards.