Abstract: Methods, systems, and devices for evaluating an earth formation intersected by a borehole. Methods may include irradiating the earth formation using a radiation source to provoke radiation from the formation responsive to the irradiation; taking a radiation measurement and thereby generating radiation measurement information by producing light scintillations from a scintillation material responsive to the absorption by the scintillation material of the radiation from the formation and substantial intrinsic radiation of the scintillation material; and estimating a parameter of interest of the earth formation using the radiation measurement information.

Abstract: A scintillation detector includes: a photodetector; a scintillating material configured to emit light in response to exposure to ionization particles; an optically transparent material having a light absorption coefficient that is less than a light absorption coefficient of the scintillating material, the optically transparent material optically coupled to a surface of the scintillating material and configured to transmit the emitted light; and a reflective material at least partially surrounding the scintillating material and the optically transparent material, the reflective material configured to reflect the emitted light and direct the emitted light toward the photodetector.

Abstract: A pulsed neutron source is used in a porosity logging tool with a single gamma ray detector coated with a neutron absorbing material. By using a ratio of the spectral peak associated with hydrogen to a spectral peak associated with the neutron absorbing material, the formation porosity is estimated.

Abstract: Disclosed is an apparatus configured to detect radiation at high temperatures in a borehole penetrating the earth. The apparatus includes a scintillation material that interacts with the radiation to generate photons, at least one solid-state photodetector optically coupled to the scintillation material and configured to detect the radiation by detecting the generated photons, and at least one optical element disposed between the scintillation material and the at least one solid-state photodetector and configured to concentrate the photons generated in the scintillation material onto the at least one solid-state photodetector.

Abstract: An instrument for performing measurements downhole includes: at least one gamma-ray detector with azimuthal sensitivity equipped for discriminating energy of incident gamma-rays. This instrument is equipped with or without a neutron or gamma-ray source. A method and computer program product providing the azimuthal sensitivity of the instrument is provided.

Abstract: A method of calculating a formation characteristic includes measuring with at least two detectors spaced apart from each other an intensity of gamma rays, and calculating the formation characteristic by calculating a ratio of the intensity of the gamma rays detected by the two detectors.

Abstract: A pulsed neutron source is used in a porosity logging tool with a single gamma ray detector coated with a neutron absorbing material. By using a ratio of the spectral peak associated with hydrogen to a spectral peak associated with the neutron absorbing material, the formation porosity is estimated.

Abstract: An apparatus for performing an operation in a borehole penetrating the earth includes a borehole tool and a neutron source within the borehole tool that emits neutron-alpha particles pairs as the result of a nuclear reaction. The apparatus also includes an alpha particle detector within the borehole tool arranged to detect when an alpha particle emitted by the neutron source strikes it and a gamma ray detector to detect gamma rays produced as a result of interactions between neutrons produced by the neutron source and at least one material in an area of interest outside of the borehole. The apparatus also includes a processing system that determines a characteristic of the area of interest based on a time difference between when the alpha particle strikes the alpha particle detector and a time when one or more gamma rays strikes the gamma ray detector.

Abstract: A scintillation detector includes: a photodetector; a scintillating material configured to emit light in response to exposure to ionization particles; an optically transparent material having a light absorption coefficient that is less than a light absorption coefficient of the scintillating material, the optically transparent material optically coupled to a surface of the scintillating material and configured to transmit the emitted light; and a reflective material at least partially surrounding the scintillating material and the optically transparent material, the reflective material configured to reflect the emitted light and direct the emitted light toward the photodetector.

Abstract: Disclosed is an apparatus configured to detect radiation at high temperatures in a borehole penetrating the earth. The apparatus includes a scintillation material that interacts with the radiation to generate photons, at least one solid-state photodetector optically coupled to the scintillation material and configured to detect the radiation by detecting the generated photons, and at least one optical element disposed between the scintillation material and the at least one solid-state photodetector and configured to concentrate the photons generated in the scintillation material onto the at least one solid-state photodetector.

Abstract: A gamma ray detector uses a scintillation detector having a response that matches a response characteristic of a photodiode. The detector may be used to measure natural gamma rays and/or gamma rays produced by interaction of neutrons from a neutron source with the earth formation.

Abstract: An apparatus for performing an operation in a borehole penetrating the earth includes a borehole tool and a neutron source within the borehole tool that emits neutron-alpha particles pairs as the result of a nuclear reaction. The apparatus also includes an alpha particle detector within the borehole tool arranged to detect when an alpha particle emitted by the neutron source strikes it and a gamma ray detector to detect gamma rays produced as a result of interactions between neutrons produced by the neutron source and at least one material in an area of interest outside of the borehole. The apparatus also includes a processing system that determines a characteristic of the area of interest based on a time difference between when the alpha particle strikes the alpha particle detector and a time when one or more gamma rays strikes the gamma ray detector.

Abstract: An instrument for performing measurements downhole includes: at least one gamma-ray detector with azimuthal sensitivity equipped for discriminating energy of incident gamma-rays. This instrument is equipped with or without a neutron or gamma-ray source. A method and computer program product providing the azimuthal sensitivity of the instrument is provided.

Abstract: A gamma ray detector uses a scintillation detector having a response that matches a response characteristic of a photodiode. The detector may be used to measure natural gamma rays and/or gamma rays produced by interaction of neutrons from a neutron source with the earth formation.

Abstract: The invention relates to devices for checking the conditions of the coolant at the output of the coolant feed unit of an electrical machine with cryogenic cooling.The device for checking the condition of the coolant comprises a hollow rotor, in which cryogenic temperature is maintained. Located inside the hollow rotor at one end and coaxially with the rotor is a coolant feed unit having a stationary part made in the form of two coaxial tubes disposed with a gap with respect to each other and a movable part. One end of the coolant feed unit communicates with a coolant supply tank while the other end communicates with a coolant collecting chamber, which, in turn, communicates with a unit for transferring the coolant into a liquid coolant receiver tank disposed at the other end of the hollow rotor and made, identically to the unit, in the form of two coaxial tubes.

Abstract: A super-conductive cryogen-cooled electrical machine comprises a rotor disposed within a hollow stator with an annular gap which is evacuated and kept under vacuum by means of at least two shells furnished with ports and position concentrically with a clearance or gap therebetween. One of said shells is supported in a cantilevered fashion by the rotor on the end face thereof to be coaxial therewith and the other being supported in a cantilevered fashion by the stator on the end face thereof opposite said end face of the rotor. The ports in the rotor-supported shells are made so that their axes form an acute angle .alpha. with tangent lines drawn to the shell periphery from the points where the port axes intersect the shell envelope in the direction of the rotor rotation, while the ports in the stator supported shells are made so as to form, in a similar way, an angle .beta.=180.degree.-.alpha..

Abstract: A super-conductive, cryogenically-cooled electrical machine comprises a superconductive exciting winding located in a hollow rotor and a system for cooling the ends of the rotor shaft. The cooling agent is delivered from one end of said shaft to the rotor space through the axial passage of the shaft whose ends are made of at least two coaxial tubes secured together by threading. The cooling agent is removed through the clearances of said thread and such construction of the rotor shaft reduces heat influxes to the superconductive exciting winding at least threefold and lowers the weight-to-power ratio of the machine at least fivefold.

Abstract: A device for delivering cryogen to a superconducting winding of a cryogen-cooled electrical machine comprising a pipe articulated along the axis of the electrical machine and intended to deliver cryogen. One end of said pipe is located in a rotary chamber which communicates through channels with the space of the electrical machine, and said space accommodating its superconducting winding. The said chamber accommodates a needle installed along the chamber axis, and the length of said needle is of sufficient length such that in the advanced position of said cryogen delivering pipe said needle reaches the end of the pipe.The layout of the electrical machine increases the reliability and effectiveness of the device for delivering cryogen to the superconducting winding, simplifies the design of the device and raises the efficiency of the electrical machine.

Abstract: A cryogenically cooled electrical machine comprises a superconducting field winding placed inside a hollow rotor surrounded by a cooled magnetic shield and a heat shield. The magnetic shield is arranged within the heat shield and is cooled by a coolant circulating in ducts made in the heat shield, the heat and magnetic shields being arranged within an evacuated space between the rotor and the shell of the electrical machine. This embodiment of the electrical machine makes it possible to increase the efficiency of thermal protection of the superconducting field winding.