An X-ray downhole imaging tool is provided and includes an X-ray tube capable of operating at least at 50 KeV and emitting at least one hundred micro-amperes of continuous electron current and a radiation detector axially displaced from the X-ray tube, at least partially shielded therefrom and radially directed. In certain embodiments, the radiation detector includes a microchannel plate and a resistive anode. In certain embodiments, a second detector which is axially directed is also provided.