A method of operating a radiation source, wherein the radiation source is a radiation source for generating invasive electromagnetic radiation in the form of X-ray radiation and includes a target having at least one target element which is configured to generate invasive electromagnetic radiation upon irradiation with particles and which is coupled to a substrate arrangement for dissipating heat from the target element, wherein the target element has a peripheral surface forming a first part of an outer surface of the target element, wherein the outer surface of the target element is additionally formed by a side surface of the target element, wherein an extent of the side surface defines a thickness (D;
- D1, D2, D3) of the target element, wherein a peripheral line of the side surface forms a marginal line of the peripheral surface, wherein the target has an end face, as part of which the side surface of the target element is arranged in an exposed manner for irradiation with the particles, and wherein the substrate arrangement is in contact with the peripheral surface, wherein the at least one target element is embodied in a layerlike manner, the at least one target element has a greater width (B) in comparison with the thickness (D), the peripheral line has a total length defined by the thickness (D) and by the width (B), the substrate arrangement is in contact with the peripheral surface at sides thereof which are opposite one another in a direction of the thickness (D);
- and, the thickness (D) of the at least one target element, embodied in a layerlike manner, increases at said side surface with increasing extent in a direction of the width (B), the radiation source including a particle beam source configured to radiate a particle beam onto the target and a positioning device configured to orient the target and the particle beam relative to one another in a variable manner such that a surface region of the target onto which the particle beam is directed is variable, the method comprising the steps of:
- directing a particle beam onto a first surface region of an end face of the target;
- and,
- varying a relative orientation of the target and the particle beam in such a way that the particle beam is directed onto a second surface region of the end face of the target;
- wherein the first surface region of the end face and the second surface region of the end face have regions, having different thicknesses, of exposed side surfaces of one or more target elements of the target.