US4883956A — Methods and apparatus for gamma-ray spectroscopy …

Claim 1

Independent Claim 57 words

Apparatus for investigation of subsurface earth formations, comprising: a sonde adapted for movement through a borehole; detector means carried by said sonde for detecting radiation and including a gadolinium orthosilicate scintillator; and means coupled to said detector means for generating and recording a signal representative of at least one characteristic of radiation detected by said detector means.

Claim 2

Dependent Claim 57 words

Apparatus for investigation of subsurface earth formations, comprising: a sonde adapted for movement through a borehole; detector means carried by said sonde for detecting radiation and including a gadolinium orthosilicate scintillator; and means coupled to said detector means for generating and recording a signal representative of at least one characteristic of radiation detected by said detector means.

Claim 3

Dependent Claim 13 words

The apparatus of claim 1, wherein said scintillator comprises a plurality of crystals.

Claim 4

Dependent Claim 18 words

The apparatus of claim 1, wherein said plurality of crystals are arranged to provide similar light output characteristics.

Claim 5

Dependent Claim 16 words

The apparatus of claim 3, wherein said crystals are selected to have matched light output characteristics.

Claim 6

Dependent Claim 20 words

The apparatus of claim 3, wherein said detector means includes filter means to match the light output of said crystals.

Claim 7

Dependent Claim 34 words

The apparatus of claim 2, wherein said detector means includes means for detecting scintillation light produced by said scintillator and each of said plurality of crystals has a face adjacent said light detecting means.

Claim 8

Dependent Claim 29 words

the apparatus of claim 1, wherein said detector means includes means for detecting scintillation light produced by said scintillator and said scintillator is integral with said light detecting means.

Claim 9

Dependent Claim 37 words

The apparatus of claim 1, wherein said signal generating and recording means includes pulse pile-up rejection means for rejecting signals corresponding to two or more superimposed scintillation events ocurring within at least 100 nanoseconds of each other.

Claim 10

Dependent Claim 104 words

A borehole photon logging scintillation detector comprising: a crystal of cerium-doped gadolinium orthosilicate having a polygonal cross-section; a photomultiplier tube having a transparent face disposed adjacent a surface of said crystal; an optical coupling medium between said photomultiplier tube face and said crystal surface; a layer of light reflective material covering said crystal except for said face; a layer of photon absorbing material around said crystal for attenuating photons having an energy below approximately 1 MeV; a layer of neutron absorbing material around said crystal and having a capture cross-section of at least 100 barns; and a housing around said crystal and said layers.

Claim 11

Dependent Claim 104 words

A borehole photon logging scintillation detector comprising: a crystal of cerium-doped gadolinium orthosilicate having a polygonal cross-section; a photomultiplier tube having a transparent face disposed adjacent a surface of said crystal; an optical coupling medium between said photomultiplier tube face and said crystal surface; a layer of light reflective material covering said crystal except for said face; a layer of photon absorbing material around said crystal for attenuating photons having an energy below approximately 1 MeV; a layer of neutron absorbing material around said crystal and having a capture cross-section of at least 100 barns; and a housing around said crystal and said layers.

Claim 12

Dependent Claim 105 words

Apparatus for investigation of subsurface earth formations, comprising: a sonde adapted for movement through a borehole; neutron source means for irradiating material in the region of said borehole with neutrons capable of interactions with said material resulting in radiation having characteristics carrying information about said material; detector means carried by said sonde for detecting radiation, said detector means including a gadolinium orthosilicate scintillator and a layer of boron-10 in the order of two millimeters in thickness for absorbing neutrons; and means coupled to said detector means for generating and recording a signal representative of at least one characteristic of radiation detected by said detector means.

Claim 13

Dependent Claim 105 words

Apparatus for investigation of subsurface earth formations, comprising: a sonde adapted for movement through a borehole; neutron source means for irradiating material in the region of said borehole with neutrons capable of interactions with said material resulting in radiation having characteristics carrying information about said material; detector means carried by said sonde for detecting radiation, said detector means including a gadolinium orthosilicate scintillator and a layer of boron-10 in the order of two millimeters in thickness for absorbing neutrons; and means coupled to said detector means for generating and recording a signal representative of at least one characteristic of radiation detected by said detector means.

Claim 14

Dependent Claim 128 words

For use in a sonde for investigating subsurface earth formations while moving through a fluid filled borehole traversing said earth formations and subjected to moisture and temperature variations during said movement, detector means adapted to be enclosed within and carried by said sonde, said detector means including a gadolinium orthosilicate scintillator substantially unaffected by the moisture in said borehole and having a variation in sensitivity with temperature over a range from 20 to 150 degrees centigrade comparable to that of thallium-doped sodium iodide, said detector means being responsive to radiation impinging on said scintillator to produce an output indication, and means coupled to said detector means and responsive to said output indication for generating and recording a signal representative of at least one characteristic of said impinging radiation.

Claim 15

Dependent Claim 128 words

For use in a sonde for investigating subsurface earth formations while moving through a fluid filled borehole traversing said earth formations and subjected to moisture and temperature variations during said movement, detector means adapted to be enclosed within and carried by said sonde, said detector means including a gadolinium orthosilicate scintillator substantially unaffected by the moisture in said borehole and having a variation in sensitivity with temperature over a range from 20 to 150 degrees centigrade comparable to that of thallium-doped sodium iodide, said detector means being responsive to radiation impinging on said scintillator to produce an output indication, and means coupled to said detector means and responsive to said output indication for generating and recording a signal representative of at least one characteristic of said impinging radiation.

Claim 16

Dependent Claim 97 words

An improved detector for radiatin emanating from materials in the region of a fluid-filled borehole traversing earth formations, said detector adapted to be carried in a sonde for movement through said borehole, said detector comprising: a scintillator responsive to radiation from said formations to produce a light output, said scintillator comprising a cerium-doped crystal of gadolinium orthosilicate substantially unaffected by moisture and having a variation in sensitivity with temperature over a range from 20 to 150 degrees centigrade comparable to that of thallium-doped sodium iodide; and means responsive to said light output to produce an electrical signal.

Claim 17

Dependent Claim 97 words

An improved detector for radiatin emanating from materials in the region of a fluid-filled borehole traversing earth formations, said detector adapted to be carried in a sonde for movement through said borehole, said detector comprising: a scintillator responsive to radiation from said formations to produce a light output, said scintillator comprising a cerium-doped crystal of gadolinium orthosilicate substantially unaffected by moisture and having a variation in sensitivity with temperature over a range from 20 to 150 degrees centigrade comparable to that of thallium-doped sodium iodide; and means responsive to said light output to produce an electrical signal.

Claim 18

Dependent Claim 17 words

The detector of claim 12 wherein said means responsive to said light output comprises a photomultiplier tube.

Claim 19

Dependent Claim 18 words

The detector of claim 13 wherein said scintillator and said photomultiplier tube are enclosed within a common envelope.

Claim 20

Dependent Claim 70 words

Apparatus for investigation of subsurface earth formations comprising: a sonde adapted for movement through a borehole; detector means carried by said sonde for detecting radiation and including a gadolinium orthosilicate scintillator; means for rendering said scintillator selectively responsive to a desired type of radiation; and means coupled to said detector means for generating and recording a signal representative of at least one characteristic of radiation detected by said detector means.

Claim 21

Dependent Claim 70 words

Apparatus for investigation of subsurface earth formations comprising: a sonde adapted for movement through a borehole; detector means carried by said sonde for detecting radiation and including a gadolinium orthosilicate scintillator; means for rendering said scintillator selectively responsive to a desired type of radiation; and means coupled to said detector means for generating and recording a signal representative of at least one characteristic of radiation detected by said detector means.

Claim 22

Dependent Claim 34 words

The apparatus of claim 15 above wherein said means for rendering said scintillator selectively responsive comprises a layer of absorbing material selected from the group comprising lead, tungsten, tungsten alloy, depleted uranium and bismuth.

Claim 23

Dependent Claim 34 words

The apparatus of claim 15 above wherein said means for rendering said scintillator selectively responsive comprises a layer of absorbing material selected from the group comprising boron-10, lithium-6, boron carbide and an artificial isotope.

Claim 24

Dependent Claim 63 words

Apparatus for investigation of subsurface earth formations comprising; a sonde adapted for movement through a borehole; detector means carried by said sonde for detecting radiation and including a single crystal gadolinium orthosilicate scintillator of generally cylindrical shape; and means coupled to said detector means for generating and recording a signal representative of at least one characteristic of radiation detected by said detector means.

Claim 25

Dependent Claim 63 words

Apparatus for investigation of subsurface earth formations comprising; a sonde adapted for movement through a borehole; detector means carried by said sonde for detecting radiation and including a single crystal gadolinium orthosilicate scintillator of generally cylindrical shape; and means coupled to said detector means for generating and recording a signal representative of at least one characteristic of radiation detected by said detector means.

Claim 26

Dependent Claim 72 words

Apparatus for investigation of subsurface earth formations comprising: a sonde adapted for movement through a borehole; detector means carried by said sonde for detecting radiation and including a gadolinium orthosilicate scintillator; said scintillator being substantially exposed to and unprotected from the temperatures encountered in said borehole; and means coupled to said detector means for generating and recording a signal representative of at least one characteristic of radiation detected by said detector means.

Claim 27

Dependent Claim 72 words

Apparatus for investigation of subsurface earth formations comprising: a sonde adapted for movement through a borehole; detector means carried by said sonde for detecting radiation and including a gadolinium orthosilicate scintillator; said scintillator being substantially exposed to and unprotected from the temperatures encountered in said borehole; and means coupled to said detector means for generating and recording a signal representative of at least one characteristic of radiation detected by said detector means.

Claim 28

Dependent Claim 14 words

The apparatus of claim 19 above, wherein said scintillator is cerium doped gadolinium orthosilicate.

Claim 29

Dependent Claim 28 words

The apparatus of claim 19 above, wherein said scintillator is a single crystal oriented with its (100) crystal plane substantially parallel to the longitudinal axis of said sonde.

Claim 30

Dependent Claim 104 words

Apparatus for investigation of subsurface earth formations comprising: a sonde adapted for movement through a borehole; source means carried by said sonde for irradiating material in the region of said borehole with penetrating radiation capable of interactions with said material resulting in radiation having characteristics carrying information about said material; detector means carried by said sonde for detecting radiation and including a gadolinium orthosilicate scintillator; means for rendering said scintillator selectively responsive to a desired type of radiation; and means coupled to said detector means for generating and recording a signal representative of at least one characteristic of radiation detected by said detector means.

Claim 31

Dependent Claim 104 words

Apparatus for investigation of subsurface earth formations comprising: a sonde adapted for movement through a borehole; source means carried by said sonde for irradiating material in the region of said borehole with penetrating radiation capable of interactions with said material resulting in radiation having characteristics carrying information about said material; detector means carried by said sonde for detecting radiation and including a gadolinium orthosilicate scintillator; means for rendering said scintillator selectively responsive to a desired type of radiation; and means coupled to said detector means for generating and recording a signal representative of at least one characteristic of radiation detected by said detector means.

Claim 32

Dependent Claim 25 words

The apparatus of claim 22 above wherein said source means comprises a source of neutrons and said scintillator is rendered selectively responsive to gamma rays.

Claim 33

Dependent Claim 23 words

The apparatus of claim 22 above wherein said source comprises a source of neutrons and said scintillator is rendered selectively responsive to neutrons.

Claim 34

Dependent Claim 24 words

The apparatus of claim 22 above wherein said source means comprises a source of photons and said scintillator is rendered selectively responsive to photons.

Claim 35

Independent Claim 60 words

A method of investigating subsurface earth formations comprising the steps of: moving a sonde carrying detector means including a gadolinium orthosilicate scintillator through a borehole in said formations; detecting radiation from material in the region of said borehole with said detector means; and generating and recording signals representative of at least one characteristic of radiation detected with said detector means.

Claim 36

Independent Claim 60 words

A method of investigating subsurface earth formations comprising the steps of: moving a sonde carrying detector means including a gadolinium orthosilicate scintillator through a borehole in said formations; detecting radiation from material in the region of said borehole with said detector means; and generating and recording signals representative of at least one characteristic of radiation detected with said detector means.

Claim 37

Dependent Claim 18 words

The method of claim 26 above, further comprising rendering said scintillator responsive to a predetermined type of radiation.

Claim 38

Dependent Claim 30 words

The method of claim 26 above, further comprising irradiating material in the region of said borehole with penetrating radiation capable of interacting with said material to induce said detected radiation.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1992-11-27	1993-05-29	1993-11-28	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1996-11-27	1997-05-29	1997-11-28	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2000-11-27	2001-05-29	2001-11-28	$7700.00	Window Closed / Lapsed

Methods and apparatus for gamma-ray spectroscopy and like measurements

Abstract

Inventors

Bibliographic Details

Claims Analysis

References Cited (Backward Citations)

USPTO Annuity & Maintenance Windows

Assigned Categories & Tags

Assign Category Tag