Abstract: A method and apparatus for communicating signals from within an encased borehole including a wireless communications system for transmitting down-hole environmental data signals between a down-hole tool and a surface receiver. The down-hole tool is disposed within a borehole encased in an electrically conductive casing; the receiver is located at the ground surface. The tool includes a conductive upper and lower tool housing, a plurality of down-hole sensors, and a signal generating device. The sensors and signal generating device are housed within the tool. The generating device receives analog or digital signals of the down-hole environmental conditions from the sensors, converts these signals into a modulation pattern signal which is applied to a carrier signal and conducts a modulated carrier signal into the upper and lower tool housings. An upper contactor or spreader electrically connects the upper housing to a first position on an inside wall of the casing.

Abstract: A position sensitive detector including a curved detector housing having a hollow detector chamber therein, the housing having an elongate opening in the curved side wall thereof and an x-ray transmissive material adjacent thereto to render the detector chamber air-tight, a back cathode plane comprising a plurality of spaced cathode conductors on an insulator support and at least one curved anode wire, extending at least substantially transverse to the back cathode plane, disposed within the detector chamber in the path of x-rays entering through the elongate opening. Each anode wire, which is mechanically supported only at the ends thereof, is caused, during operation of the detector, to be supported in planar arcuate form solely by electrostatic forces. During operation of the detector, the chamber is filled with an ionizable gas and voltage is applied to the curved anode wire(s), thereby enabling detection of ionizing events occuring within the detector chamber.