Schlumberger Technology Corporation

University of California

Services Petroliers Schlumberger

Schlumberger Holdings Limited

Prad Research and Development Limited

Jani Petteri Reijonen

Matthieu Simon

Ka-Ngo Leung

Peter D Wraight

Kenneth Edward Stephenson

Luke T Perkins

Irina Molodetsky

Marc-Andre De Looz

Joel Lee Groves

Anthony Durkowski

Frederic Gicquel

Leo Chirovsky

Christian Stoller

Harold Pfutzner

Qing Ji

Arun Persaud

Vincent Ernst

Tak Pui Lou

Kevin Lee Hiles

Justin Dale Mlcak

Ximan Jiang

Kevin Stephen McFarland

Frederic Gicquiel

Richard B Firestone

Darren Gould

Rainer W Thomae

Joel Mark Wiedemann

Giovana Stefan

Austin Jones

Loic Vilde

A beam injector may include a cathode emitter to emit electrons and an electrode to bias at least a portion of the electrons to remain on the cathode emitter and focus the emitted electrons into an electron beam. The beam injector may also include a resistor coupled between the cathode emitter and the electrode and configured to allow self-regulation of a voltage potential on the electrode based at least in part on a current of the electron beam.

Regulated charged particle beam emitter systems and methods

The present disclosure relates to a downhole tool that includes a first photon flux detector disposed at a first radial position about a longitudinal axis of the downhole tool that measures a first signal indicative of an x-ray flux of the x-ray photons. The downhole tool also includes a second photon flux detector disposed at a second radial position about the longitudinal axis of the downhole tool that measures a second signal indicative of the x-ray flux of the x-ray photons. Further, the downhole tool includes a controller communicatively coupled to the first photon flux detector and the second photon flux detector that determines a condition associated with the electron beam based at least in part on a relative x-ray flux from the first photon flux detector and the second photon flux detector.

Beam alignment systems and method

A downhole tool may include a high-voltage power supply disposed within a housing to transform input power to the downhole tool from a first voltage to a second voltage greater than the first voltage. The high-voltage power supply may include an array of capacitors, which may include multiple rows of capacitors. The rows of capacitors may be parallel with a symmetric cross section as viewed from an end of the array of capacitors. The high-voltage power supply may also include diodes electrically coupled to the array of capacitors.

Compact high-voltage power supply systems and methods

A downhole tool may include a voltage multiplier within a housing. The voltage multiplier may transform input power to the downhole tool from a first voltage to a second voltage higher than the first. The downhole tool may also include multiple shielding rings surrounding at least the voltage multiplier to reduce electric field stresses within the downhole tool. Additionally, the downhole tool may include an insulator located between the shielding rings and the housing.

High-voltage protection and shielding within downhole tools

A apparatus may include a power supply to receive a first voltage potential and output a second voltage potential that is greater than the first voltage potential and a cathode emitter to emit ions in response to application of the second voltage potential. The apparatus may also include a step down transformer to receive the second voltage potential and output a third voltage potential that is less than the second voltage potential. The apparatus may also include a heating element to, in response to application of the third voltage potential, heat the cathode emitter and lower a work function of the cathode emitter.

Compact high-voltage power supply and radiation apparatus systems and methods

An electronic radiation generator may include a target material that emits radiation in response to being struck by an accelerated electron beam, an accelerator chamber that accelerates the electron beam toward the target, and a cathode emitter that emits electrons from an exposed surface of a thermionic emission material of the cathode emitter. The cathode emitter may have a thermionic emission material that is partially covered and partially exposed by a protective layer, which may focus the electron beam. Additionally or alternatively, an aperture assembly may form an aperture in front of the cathode emitter in relation to the target. The aperture assembly may at least partially block the exposed surface of the thermionic emission material in relation to the target. Since the aperture shapes the electron beam, the aperture causes the electron beam to remain more stable even when the cathode emitter shakes or vibrates.

Charged particle emitter assembly for radiation generator

A compact radiation generator for use in a downhole well-logging tool is disclosed. The compact radiation generator comprises a housing with a cavity, a linear acceleration tube in the cavity that generates radiation when supplied with a sufficiently high voltage, and a first voltage multiplier ladder in the cavity configured to supply the sufficiently high voltage to the acceleration tube. The first voltage multiplier ladder is folded into two linear parts that are collocated to each other.

Collocation of radiation generator components for limited-space devices

A system comprises a voltage multiplier ladder, a driver that provides an input voltage to the voltage multiplier ladder, and a controller that regulates the driver such that a voltage stress in the ladder is evenly distributed and do not exceed a maximum allowable stress and meanwhile the ladder is operating at an optimal efficiency.

Systems and methods for controlling a voltage multiplier ladder for optimal efficiency and minimal component stress

A radiation generator may include an elongate generator housing having a proximal end and a distal end, a target electrode within the housing at the distal end thereof, a charged particle source within the housing at the proximal end thereof to direct charged particles at the target based upon a first biasing potential, and a field shaping electrode within the housing and adjacent the source to shape a field within the housing. At least one accelerator electrode may be within the housing on an opposite side of the field shaping electrode from the source to accelerate charged particles from the source to the target based upon a second biasing potential different than the first biasing potential. The field shaping electrode may be electrically floating so that the charged particles are directed from the source to the target without applying a biasing potential to the field shaping electrode.

Radiation generator with field shaping electrode

Systems, methods, and devices with improved electrode configuration for downhole nuclear radiation generators are provided. For example, one embodiment of a nuclear radiation generator capable of downhole operation may include a charged particle source, a target material, and an acceleration column between the charged particle source and the target material. The acceleration column may include an intermediate electrode that remains floating at a variable potential, being electrically isolated from the rest of the acceleration column.

Floating intermediate electrode configuration for downhole nuclear radiation generator

A radiation generator may include an elongate generator housing having a proximal end and a distal end, a target electrode within the elongate generator housing at the distal end thereof, a charged particle source within the elongate generator housing at the proximal end thereof to direct charged particles at the target electrode. A plurality of accelerator electrodes may be spaced apart within the elongate generator housing between the target electrode and the charged particle source to define a charged particle accelerator section. Each accelerator electrode may include an annular portion having a first opening therein, and a frustoconical portion having a base coupled to the first opening of the annular portion and having a second opening so that charged particles from the charged particle source pass through the first and second openings to reach the target electrode.

Radiation generator with frustoconical electrode configuration

A method for operating a pulsed neutron generator including an ionizer with an electron emitting cathode and a grid wherein the cathode and grid are disposed in a sealed chamber. At least one of the following is applicable to the ionizer; a distance between the cathode and the grid, a cathode current and/or a potential on the grid are selected such that the ionizer operates at most about one-half the space charge limited current for a grid current selected to provide a predetermined amount of neutron production.

Pulsed neutron generator tube design which extends the lifetime of a cathode

A well-logging apparatus may include a charged particle source, a target electrode, and an accelerator column. The accelerator column may include a housing extending between the charged particle source and the target electrode, a series of spaced apart accelerator electrodes carried by the housing, a series of ring-shaped resistors surrounding the housing, and a respective connector coupling adjacent ones of the series of ring-shaped resistors together and to a corresponding one of the series of spaced apart accelerator electrodes.

Well-logging apparatus with ring-shaped resistors and related methods

Systems, methods, and devices with improved electrode configuration for downhole nuclear radiation generators are provided. For example, one embodiment of a nuclear radiation generator capable of downhole operation may include a charged particle source, a target material, and an acceleration column between the charged particle source and the target material. The acceleration column may include several electrodes shaped such that substantially no electrode material from the electrodes is sputtered onto an insulator surface of the acceleration column during normal downhole operation.

Growing community of inventors

Princeton, NJ, United States of America

Jani Petteri Reijonen