In one embodiment, an X-ray source is provided that includes one or more electron emitters configured to emit one or more electron beams and one or more source targets configured to receive the one or more electron beams emitted by the one or more electron emitters and, as a result of receiving the one or more electron beams, to emit X-rays. Each source target of the X-ray source includes a first layer having one or more first materials; and a second layer in thermal communication with the first layer and having one or more second materials. The first layer is positioned closer to the one or more emitters than the second layer, the first material has a higher overall thermal conductivity than the second layer, and the second layer produces the majority of the X-rays emitted by the source target.