317results about "Magnetic gradient measurements" patented technology

A magnetic sensor arrangement (1), having magnetically sensitive sensor elements (7, 8) whose electrical properties are changeable as a function of a magnetic field that a moving, passive transmitter element (11) is able to influence. The magnetic sensor arrangement (1) has two sensor elements (7, 8) in a gradiometer arrangement that are each respectively associated with one of two magnetic regions (4, 5) of a permanent magnet embodied in the form of a gap magnet (2; 20; 23), which regions are spaced apart from each other by a predetermined distance (sa). The regions (4, 5) and the gap magnet (2; 20; 23)—in terms of the for example wedge-shaped embodiment, the dimensions (h, b, t), the gap width (sa), the gap depth (st), and their positions in relation to the sensor elements (7, 8)—are situated so as to minimize the offset of the output signal of the sensor elements (7, 8) in the gradiometer arrangement.

An atomic magnetometer includes a light source for a probe beam and a medium in which the probe beam is to be propagated. The medium is a substance which changes a polarization rotation angle of the probe beam depending on a magnetic field intensity at a first measurement position and a magnetic field intensity at a second measurement position different from the first measurement position. The atomic magnetometer directly measures a difference between the magnetic field intensity at the first measurement position and the magnetic field intensity at the second measurement position as a difference in polarization rotation angle, along a propagation path of the probe beam.

A gradiometer in which a probe beam for reading sequentially passes through two magnetic field measurement regions to obtain signals according to magnetic flux densities of the respective regions is formed using an optically pumped magnetometer. In particular, in a gradiometer using a high sensitivity optically pumped magnetometer, a geometric arrangement enabling obtainment of a large signal from a dipole moment as a signal source is defined.

The invention discloses a magnetic resistance Z-axis gradient sensor chip which is used for detecting the gradients of components of a Z-axis magnetic field generated by magnetic media in the X-Y plane so as to conduct magnetic imaging on the magnetic media. The magnetic resistance Z-axis gradient sensor chip comprises a Si substrate, two or two groups of sets containing a plurality of flux leaders and magnetic resistance sensing units which are electrically connected, wherein the distance between the sets is Lg. The magnetic resistance sensing units are located on the Si substrate and located above or below the edges of the flux leaders, the components of the Z-axis magnetic field are converted into the mode that the components of the Z-axis magnetic field are parallel to the surface of the Si substrate and in the direction of the sensitive axes of the magnetic resistance sensing units, and the magnetic resistance sensing units are electrically connected into a half-bridge or whole-bridge gradient meter, wherein the distance between opposite bridge arms is Lg. The sensor chip can be used together with a PCB, a PCB and back magnetor a PBC and back magnet and packaging shell. According to the magnetic resistance Z-axis gradient sensor chip, measurement of the Z-axis magnetic field gradient is achieved by using plane sensitive magnetic resistance sensors, and the magnetic resistance Z-axis gradient sensor chip has the advantages of being small in size and low in power consumption, having higher magnetic field sensitivity than a Hall sensor and the like.

An apparatus for measuring and detecting a magnetic signature of a magnetically detectable object from a distance includes a portable sensor group for detecting the magnetic signature. The portable sensor group includes three gradient sensors, each of the three gradient sensors adapted to independently measure both a magnitude and a direction of the magnetic signature, a first of said gradient sensors measuring an axial gradient in the vertical direction, a second of said gradient sensors measuring a first horizontal gradient in the vertical direction, and a third of said gradient sensors measuring a second horizontal gradient in the vertical direction.

A magnetic sensor system (1) is provided that contains sensor elements (5, 6) that are sensitive to magnetic fields, the electrical properties of said sensor elements being modifiable according to a magnetic field that can be influenced by a mobile, passive transmitter element (8). The magnetic sensor system (1) includes two sensor elements (5, 6) in a gradiometer system, each of which is assigned to one of two permanent magnets (2, 3) having a predetermined separation. In terms of their dimensions, separation and position relative to the sensor elements (5, 6), the permanent magnets (2, 3) are located such that the offset of the output signal of the sensor elements (5, 6) is minimized in the gradiometer system.

The invention relates to a method of selecting a set of coil elements from a multitude of physical coil elements comprised in a coil array for performing a magnetic resonance imaging scan of a region of interest.