Directional gamma ray spectrometer
First Claim
1. A directional gamma ray spectrometer comprising:
- (a) an elongate scintillation device responsive to impinging gamma rays, said device having spaced ends and having an elongate outer surface shaped as a cylinder;
(b) end located scintillation responsive means for forming output indicative of scintillation events of said device;
(c) a surrounding sleeve about said device(i) along the length thereof in the form of a single turn helix;
(ii) formed of a material attenuating gamma rays to a specified degree; and
(iii) having a window formed therein wherein the window encircles to defined a directional radiation bias and wherein the directional bias is a specified range of azimuth.
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Accused Products
Abstract
This disclosure is directed to a scintillation crystal surrounded by a sleeve and having a window formed therein. The scintillation crystal has end located first and second photomultiplier tubes which provide output signals. A scintillation event observed in the crystal is seen by both photomultiplier tubes and both form output signals. The output signals have a relationship determining the point of impingement along the length of crystal of the photon gamma radiation; in turn, that photon is located relative to a surrounding shield having a helical window formed therein so that the relative angle of impingement can be determined. The relative angle is then converted into the absolute angle relative to the well borehole by referencing a north seeking gyroscope supported by the sonde. The output signals are also used to determine the energy of the impinging gamma radiation using well known pulse height analysis spectroscopy techniques.
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Citations
18 Claims
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1. A directional gamma ray spectrometer comprising:
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(a) an elongate scintillation device responsive to impinging gamma rays, said device having spaced ends and having an elongate outer surface shaped as a cylinder; (b) end located scintillation responsive means for forming output indicative of scintillation events of said device; (c) a surrounding sleeve about said device (i) along the length thereof in the form of a single turn helix; (ii) formed of a material attenuating gamma rays to a specified degree; and (iii) having a window formed therein wherein the window encircles to defined a directional radiation bias and wherein the directional bias is a specified range of azimuth. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of determining azimuthal direction of a gamma ray source relative to a well borehole comprising the steps of:
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(a) positioning an elongate scintillation means in a well borehole for exposure to gamma radiation; (b) positioning a gamma radiation attenuation shield around the scintillation responsive means having a lengthwise window formed therein wherein the window is uniquely exposed in specific azimuthal directions along the length of the scintillation responsive means; (c) observing scintillation events in the scintillation responsive means from spaced ends thereof so that two outputs of an event are observed and are represented by two output signals; and (d) as a function of the two output signals, determining the direction of gamma radiation impingement relative to said scintillation responsive means. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification