An x-ray based litho-density tool for measurement of simultaneous invaded and non-invaded formation surrounding a borehole is provided, the tool including at least an internal length comprising a sonde section, wherein sonde section further includes an x-ray source; at least one radiation measuring detector; at least one source monitoring detector; and a plurality of sonde-dependent electronics. In various embodiments, the tool uses x-rays to illuminate the formation surrounding a borehole, and a plurality of detectors are used to directly measure both invaded and non-invaded formation bulk densities. Detectors used to measure borehole standoff such that other detector responses may be compensated for tool standoff; long and ultra-long space detectors disposed in electromagnetic communication with a source located within a collimated tungsten radiation shield; and wear-pads disposed such that the source and detector assembly may be pressed against the side of the borehole to reduce borehole effects are also provided.