Abstract: The invention relates to a for a targeted shaping of the magnetic field of a single permanent magnet or an arrangement of a plurality of permanent magnets, wherein magnetic material from selected locations of the single permanent magnet or at least one of said permanent magnets of the arrangement is removed by means of at least one of the following removal procedures for shaping the magnetic field: laser ablation using laser radiation, high-pressure waterblasting using high-pressure water jets and mechanical ablation using a non-magnetic tool.

Abstract: The invention relates to a for a targeted shaping of the magnetic field of a single permanent magnet or an arrangement of a plurality of permanent magnets, wherein magnetic material from selected locations of the single permanent magnet or at least one of said permanent magnets of the arrangement is removed by means of at least one of the following removal procedures for shaping the magnetic field: laser ablation using laser radiation, high-pressure waterblasting using high-pressure water jets and mechanical ablation using a non-magnetic tool.

Abstract: A method for performing magnetic resonance measurements on a sample includes applying a first predetermined number of pulse trains for excitation, each pulse train having a constant amplitude and including a second predetermined number of pulses spaced by a predetermined time interval. The pulse trains are modulated by a bent function. After each pulse, data is sampled. Preferably a square number of pulses is generated being constant in power, and the Walsh transform of the sequence of their phases is constant in power, so that the power of the excitation in time and frequency domain is constant. The method can reduce power requirements and may permit undercutting specific absorption rate (SAR) limits due to the small excitation power necessary to create time signals with reasonable signal to noise ratio.

Abstract: System and methods for designing and using single-sided magnet assemblies for magnetic resonance imaging (MRI) are disclosed. The single-sided magnet assemblies can include an array of permanent magnets disposed at selected positions. At least one of the permanent magnets can be configured to rotate about an axis of rotation in the range of at least +/?10 degrees and can include a magnetization having a vector component perpendicular to the axis of rotation. The single-sided magnet assemblies can further include a magnet frame that is configured to hold the permanent magnets in place while allowing the at least one of the permanent magnets to rotate about the axis of rotation.

Abstract: A nuclear magnetic resonance (NMR) method for detecting hydrogen peroxide includes stimulating a spin signal in a liquid sample in a static magnetic field by exciting the sample with a first electromagnetic pulse having a frequency corresponding to a hydrogen NMR frequency; after a first time period, refocusing the spin signal by a series of second electromagnetic pulses also having the NMR-corresponding frequency and separated by a first echo time, while sampling a first train of spin signals; and refocusing the spin signal by a series of third electromagnetic pulses having the NMR-corresponding frequency and separated by a second echo time while sampling a second train of spin signals, the second echo time different from the first echo time. First and second spin-spin relaxation times are derived from the trains of spin signals, and a quotient of the spin-spin relaxation times indicates the presence of hydrogen peroxide.

Abstract: A magnet arrangement includes (a) a first and a second head ring magnet each having a substantially circular geometry with respect to a center axis and (b) a central ring magnet having a substantially circular geometry with respect to a center axis. The central ring magnet is disposed between the first and second head ring magnet in direction of the center axis. At least one of the magnets includes a first number of first magnets having at least one trapezoidal cross section and a second number of second magnets having at least one rectangular cross section. The second magnets are disposed in between the first magnets in circumferential direction. With this geometrical arrangement, magnets having a trapezoidal cross section include a guidance for a magnet having a rectangular cross section allowing the movements in radial direction of these last magnets.

Abstract: An apparatus for providing a sensitive volume for single-sided NMR includes: (i) at least one first permanent magnet for providing a first magnetic field at the sensitive volume; and (ii) at least one of the following means for superimposing at least one second magnetic field for homogenizing the first magnetic field in the sensitive volume: (A) at least one shim magnet, (B) at least one pair of shim magnets, and (C) at least one electrical conductor being connectable to an electric current source. The at least one second magnetic field is adjusted such that the magnetic field homogeneity in the sensitive volume is corresponding to a line width of hydrogen (1H) of less than 10 ppm.

Abstract: A method for performing magnetic resonance measurements on a sample includes applying a first predetermined number of pulse trains for excitation, each pulse train having a constant amplitude and including a second predetermined number of pulses spaced by a predetermined time interval. The pulse trains are modulated by a bent function. After each pulse, data is sampled. Preferably a square number of pulses is generated being constant in power, and the Walsh transform of the sequence of their phases is constant in power, so that the power of the excitation in time and frequency domain is constant. The method can reduce power requirements and may permit undercutting specific absorption rate (SAR) limits due to the small excitation power necessary to create time signals with reasonable signal to noise ratio.

Abstract: System and methods for designing and using single-sided magnet assemblies for magnetic resonance imaging (MRI) are disclosed. The single-sided magnet assemblies can include an array of permanent magnets disposed at selected positions. At least one of the permanent magnets can be configured to rotate about an axis of rotation in the range of at least +/?10 degrees and can include a magnetization having a vector component perpendicular to the axis of rotation. The single-sided magnet assemblies can further include a magnet frame that is configured to hold the permanent magnets in place while allowing the at least one of the permanent magnets to rotate about the axis of rotation.

Abstract: A nuclear magnetic resonance (NMR) method for detecting hydrogen peroxide includes providing a liquid sample in a static magnetic field; stimulating a spin signal in the sample by exciting the sample with a first electromagnetic pulse having a frequency corresponding to the hydrogen NMR frequency in the static magnetic field; waiting for a first time period; refocusing the spin signal in the sample for a first number of times by a series of second electromagnetic pulses having a frequency corresponding to the hydrogen NMR frequency in the static magnetic field, said second electromagnetic pulses being separated by a first echo time, while sampling a first train of spin signals in between the second electromagnetic pulses; and refocusing the spin signal in the sample for a second number of times by a series of third electromagnetic pulses having a frequency corresponding to the hydrogen frequency in the static magnetic field, said third electromagnetic pulses being separated by a second echo time while samplin

Abstract: An apparatus for providing a sensitive volume for single-sided NMR includes: (i) at least one first permanent magnet for providing a first magnetic field at the sensitive volume; and (ii) at least one of the following means for superimposing at least one second magnetic field for homogenizing the first magnetic field in the sensitive volume: (A) at least one shim magnet, (B) at least one pair of shim magnets, and (C) at least one electrical conductor being connectable to an electric current source. The at least one second magnetic field is adjusted such that the magnetic field homogeneity in the sensitive volume is corresponding to a line width of hydrogen (1H) of less than 10 ppm.

Abstract: A magnet arrangement includes (a) a first and a second head ring magnet each having a substantially circular geometry with respect to a centre axis and (b) a central ring magnet having a substantially circular geometry with respect to a centre axis. The central ring magnet is disposed between the first and second head ring magnet in direction of the centre axis. At least one of the magnets includes a first number of first magnets having at least one trapezoidal cross section and a second number of second magnets having at least one rectangular cross section. The second magnets are disposed in between the first magnets in circumferential direction. With this geometrical arrangement, magnets having a trapezoidal cross section include a guidance for a magnet having a rectangular cross section allowing the movements in radial direction of these last magnets.

Abstract: A low-cost single-sided NMR sensor to produce depth profiles with microscopic spatial resolution is presented. The open geometry of the NMR sensor provides a non-invasive and non-destructive testing method to characterize the depth structure of objects of arbitrary size. The permanent magnet geometry generates one plane of constant magnetic field intensity parallel to the scanner surface. By combining the highly uniform static gradient with selective RF excitation, a thin flat sensitive slice can be defined. By moving the relative position between the slice and the object, one-dimensional profiles of the near surface of large samples are produced with high spatial resolution.

Abstract: A low-cost single-sided NMR sensor to produce depth profiles with microscopic spatial resolution is presented. The open geometry of the NMR sensor provides a non-invasive and non-destructive testing method to characterize the depth structure of objects of arbitrary size. The permanent magnet geometry generates one plane of constant magnetic field intensity parallel to the scanner surface. By combining the highly uniform static gradient with selective RF excitation, a thin flat sensitive slice can be defined. By moving the relative position between the slice and the object, one-dimensional profiles of the near surface of large samples are produced with high spatial resolution.

Abstract: In a unilateral NMR probe for the analysis of a material comprising at least one magnet for generating a constant time-invariant polarization field B0 in the material to be analyzed and current conductors forming a radio frequency oscillation circuit for generating a pulsed radio frequency magnetic excitation field B1 which is superimposed on the polarization field N0 in the material, the circuit conductors are so designed as to provide several adjacent excitation fields B0 with alternatingly oppositely oriented magnetic fields, whereby the current conductors generating each one of the excitation fields have a distance from each other which causes a certain penetration depth in the material to be analyzed and echoes received therefrom provide measurement values which are characteristic for the material being analyzed.

Abstract: Stochastic pulsing using random or pseudo-random sequences is used for determination of nuclear spin properties of earth formations. This reduces the power requirements. Processing of the received signals may include linear or nonlinear cross-correlation with the excitation pulse sequence. Inversion of the results of the processing gives the desired nuclear spin property.

Abstract: In a unilateral NMR probe for the analysis of a material comprising at least one magnet for generating a constant time-invariant polarization field B0 in the material to be analyzed and current conductors forming a radio frequency oscillation circuit for generating a pulsed radio frequency magnetic excitation field B1 which is superimposed on the polarization field N0 in the material, the circuit conductors are so designed as to provide several adjacent excitation fields B0 with alternatingly oppositely oriented magnetic fields, whereby the current conductors generating each one of the excitation fields have a distance from each other which causes a certain penetration depth in the material to be analyzed and echoes received therefrom provide measurement values which are characteristic for the material being analyzed.

Abstract: In a method for generating measurement signals in time constant inhomogeneous magnetic fields, which are produced by a NMR-MOUSE apparatus in the surrounding medium, a static magnetic polarization field B0 and a pulsed magnetic polarization field B1 are generated, whereby echo signals S are generated which are measured, and an additional pulsed or oscillating magnetic field Bz is provided, which affects the echo signals S so as to generate contrasts for the measuring locations of the echo signals.

Abstract: Stochastic pulsing using random or pseudo-random sequences is used for determination of nuclear spin properties of earth formations. This reduces the power requirements. Processing of the received signals may include linear or nonlinear cross-correlation with the excitation pulse sequence. Inversion of the results of the processing gives the desired nuclear spin property.

Abstract: An apparatus for and a method of single-sided MRI with a palm-sized probe. The probe includes a planar permanent magnet having a gap between the north and south poles of the magnet. Positioned in the gap are an RF coil and a pair of gradient coils. The gradient coils are located on either side of the RF coil. The probe further includes an RF tuning circuit and a gradient input. In use, the pair of gradient coils produce a controlled magnetic field gradient over the field of view thereby improving image resolution.