A system for magnetic detection includes a nitrogen vacancy (NV) diamond material comprising a plurality of NV centers, a radio frequency (RF) excitation source configured to provide RF excitation to the NV diamond material, an optical excitation source configured to provide optical excitation to the NV diamond material, an optical detector configured to receive an optical signal emitted by the NV diamond material, and a controller. The optical signal is based on hyperfine states of the NV diamond material. The controller is configured to detect a gradient of the optical signal based on the hyperfine states emitted by the NV diamond material.

Dnv magnetic field detector

A device includes a propulsion unit configured to move the device and a steering unit configured to control the direction of the device. The device also includes a power unit configured to provide power to the propulsion unit and a charging unit configured to use an electric field to provide electrical power to the power unit. The device further includes a first magnetic sensor configured to determine a vector of one or more magnetic fields and a processor communicatively coupled to the propulsion unit, the steering unit, the power unit, and the magnetic sensor. The processor is configured to receive, from the magnetic sensor, a time-varying signal indicative of a magnetic field and determine, based on the time-varying signal, that the magnetic field is associated with an electrical power transmission line. The processor is further configured to cause the steering unit to direct the device toward the electrical power transmission line.

In-situ power charging

A system for magnetic detection of an external magnetic field is disclosed. The system includes a nitrogen vacancy (NV) diamond material comprising a plurality of NV centers, a magnetic field generator that generates a magnetic field, a radio frequency (RF) excitation source that provides RF excitation, an optical excitation source that provides optical excitation, an optical detector that receives an optical signal emitted by the NV diamond material, and a controller. The controller is configured to calculate a control magnetic field, control the magnetic field generator to generate the control magnetic field, receive a light detection signal from the optical detector based on the optical signal due to the sum of the generated control magnetic field and the external magnetic field, store measurement data based on the received light detection signal, and calculate a vector of the external magnetic field based on the stored measurement data.

Apparatus and method for recovery of three dimensional magnetic field from a magnetic detection system

A method for mapping and monitoring of hydraulic fracture includes capturing, using an array of sensors, a first magnetic image of a well pay zone. A second magnetic image is captured using the array of sensors, after a well bore is padded with a fluid. A background is established based on the first and the second magnetic images. A third magnetic image is captured using the array of sensors, after a doped proppant is injected into a stage. The third image is processed to subtract the background and to obtain information regarding distribution of the fluid and the proppant in the stage.

Mapping and monitoring of hydraulic fractures using vector magnetometers

A system for magnetic detection may include a nitrogen vacancy (NV) diamond material, a radio frequency (RF) excitation source, an optical excitation source, an optical detector, a magnetic field generator, and a controller. The controller may control the excitation sources to apply a first pulse sequence. The controller may receive a first light detection signal due to the first pulse sequence, measure first and second values of the first light detection signal at first and second reference periods, and compute a first measurement. The controller may further control the excitation sources to apply a second pulse sequence, receive a second light detection signal due to the second pulse sequence, measure first and second values of the second light detection signal at first and second reference periods, and compute a second measurement. The first and second measurements may be based on high and low resonance frequencies of the NV diamond material.

Apparatus and method for high sensitivity magnetometry measurement and signal processing in a magnetic detection system

A differential pressure transducer for measuring external pressures is disclosed. The pressure transducer uses a ferrofluid contained in two interconnecting chambers, enclosed by two non-magnetic spring diaphragms. In this embodiment, two independent inductance series circuits, each comprising a bar magnet, Hall effect sensor and an iron pole piece, measure variations in the volume of ferrofluid in each of the interconnecting chambers. Changes in pressure displace the non-magnetic spring diaphragms causing the volume in each interconnecting chamber to change in a differential manner. The flux path in the series magnetic circuit is distorted by changes in the volume of the ferrofluid, causing changes in the flux density at the sensing area of the Hall effect sensor, this sensor producing an electrical signal proportional to the flux change. The differential output of the two Hall Effect sensors contained in the two series magnetic circuits produce an electrical signal proportional to the applied differential pressure.

Differential pressure transducer utilizing a variable ferrofluid keeper as an active magnetic circuit element

A method for determining the value of a physical variable such as pressure, distance, volume or the like, comprises the following steps:
 a) Generating a magnetic flux density distribution (44.1, 44.2) in a volume (42) filled with a ferrofluid (43); b) changing the volume (42) responsive to the value of the physical variable; c) measuring the variation of the flux density distribution (44.1, 44.2) which is caused by the change of the volume (2) in order to determine the value of the physical variable. A differential pressure transducer according to the method uses a ferrofluid contained in two interconnecting chambers, enclosed by two non-magnetic spring diaphragms. At least one inductance circuit measures the variations in the volumes of ferrofluid in the interconnecting chambers. Changes in pressure displaces the non-magnetic spring diaphragms, causing the volume in each in the connecting chamber to change in a differential manner.

Robert A. Moss

Papers

Differential pressure transducer utilizing a variable ferrofluid keeper as an active magnetic circuit element

Method for determining the value of a physical variable and transducer according to the method.