Patent ID: 8742328

Claim:
A logging-while-drilling tool comprising: a circumferential drill collar; a chassis disposed radially interior to the drill collar; an electronic X-ray generator disposed within the chassis, wherein the electronic X-ray generator is configured to emit X-rays out of the logging-while-drilling tool and into a subterranean formation; a first X-ray detector disposed in the chassis at an axial location and configured to detect X-rays that return to the logging-while-drilling tool at a first collimation angle after scattering in the subterranean formation; and a second X-ray detector disposed in the chassis at the axial location of the first X-ray detector but at a different circumferential location than the first X-ray detector and configured to detect X-rays that return to the logging-while-drilling tool at a second collimation angle different than the first collimation angle after scattering in the subterranean formation; wherein the circumferential drill collar comprises a first X-ray-permissive window configured to permit X-rays emitted by the X-ray generator to exit the circumferential drill collar and a second X-ray-permissive window configured to permit some X-rays to enter the circumferential drill collar to be detected by the first X-ray detector; wherein the first and second x-ray permissive windows comprise beryllium with a corrosion resistant layer of material on an external surface thereof.