Abstract: A system for converting an electron beam into a photon beam includes an electron accelerator configured for generating an electron beam of accelerated electrons along an irradiation axis (Z); a scanning unit; a focusing unit for forming a focused beam converging towards a first focusing point (Fx) located on the irradiation axis (Z); a converting unit located between the focusing unit and the first focusing point (Fx), and comprising one or more bremsstrahlung converters, configured for converting the focused beam into a photon beam, wherein the one or more bremsstrahlung converters are curved such that the focused beam intersects each of the one or more bremsstrahlung converters with an intersecting angle comprised between 65° and 115° at all points, preferably between 75° and 105° at all points; and a target holder configured for holding a target.