Abstract: A material having magnetic permeability at r.f. frequency, for example a microstructured magnetic material has a magnetic permeability of negative value but unity magnitude over a particular r.f. frequency range. The singularity in the flux pattern has the result that magnetic resonant disturbances in a plane C,E normal to the line C,D are focussed into a plane D,F also normal to the line C,D and vice versa. This is particularly applicable to magnetic resonance apparatus, since the material can be used to transfer the r.f. magnetic flux distribution in a target region in a patient, for example at C,E to D,F where the flux may be directly measured by receive coils. Equally, transmit coils may generate flux to be focussed into the target region by the material. Magnetic resonance apparatus may be constructed which does not require gradient coils, and r.f. hypothermia may be carried out in a focussed way, minimising damage to surrounding tissue.

Abstract: In magnetic resonance imaging apparatus, an array of coils (7, 8, 9, 10) is used to receive magnetic resonance signals from a desired region of a patient. Screens 11 to 13 and 14 and 15 are provided between the coils and at the ends of the array of coils to control the sensitive region A of each coil but, in accordance with the invention, the screening properties of the screens is controllable so that for example the screens may be made inoperative beneath the plane of the array of coils so that each has the field of view B, in order to vary the properties produced by the array. Other uses of screens are described.

Abstract: Nuclear magnetic resonance methods for extracting information about a fluid in a rock are described. A system of nuclear spins in the fluid are prepared in a driven equilibrium, and a series of magnetic resonance signals generated from the fluid. The series of magnetic resonance signals is detected and analyzed to extract information about the fluid in the rock.

Abstract: Microcoils can be used in medical devices to enhance RF response signals and to create fields to enhance imaging capability in MRI imaging systems. An improved microcoil design includes a device to be inserted into a patient comprising a solid body having at least one pair of radially opposed microcoils physically associated with the solid body, each microcoil having an outside microcoil diameter of 6 mm or less, individual windings of each microcoil together defining a geometric plane for each microcoil, and the plane of each microcoil being parallel to the plane of another microcoil in the pair of radially opposed microcoils.

Abstract: A method for manufacturing NMR measurement-while-drilling tool having the mechanical strength and measurement sensitivity to perform NMR measurements of an earth formation while drilling a borehole, and a method and apparatus for monitoring the motion of the measuring tool in order to take this motion into account when processing NMR signals from the borehole. The tool has a permanent magnet with a magnetic field direction substantially perpendicular to the axis of the borehole, a steel collar of a non-magnetic material surrounding the magnet, antenna positioned outside the collar, and a soft magnetic material positioned in a predetermined relationship with the collar and the magnet that helps to shape the magnetic field of the tool. Due to the non-magnetic collar, the tool can withstand the extreme conditions in the borehole environment while the borehole is being drilled.

Abstract: Nuclear magnetic resonance logging methods that detect and analyze a steady state free precession (SSFP) signal are described. In some embodiments, Carr-Purcell-Meiboom-Gill (CPMG) spin echoes are detected along with the SSFP signals. From the SSFP signal, either alone or in combination with CPMG signals, information about a region of an earth formation, such as porosity, bound fluid volume and diffusion, may be extracted.

Abstract: A side-looking NMR logging tool incorporates a permanent magnet arrangement having a magnetization direction oriented towards a side of the tool and a dipole RF antenna displaced towards the front of the tool. The magnet arrangement produces a shaped region of investigation in front of the tool wherein the magnetic field has a uniform field strength and the RF field has a uniform field strength in a direction orthogonal to the static field. The shaping of the static field is accomplished by the magnet arrangement comprising a plurality of magnets having parallel magnetization or by a single shaped magnet. The antenna arrangement includes a gapped core made of non-ferritic soft material for increasing the antenna efficiency. The magnet arrangement also reduces ringing in the core and the antenna. An optional RF shield is used to reduce NMR signals from borehole fluids.

Abstract: Modular expandable hyperpolarizers include a central control module and at least one optical pumping module that can be expandable to a plurality of optical pumping modules that can be separately operated depending on the capacity demands at the production site (hospital, clinic and the like). Methods for producing blended polarized gas products include introducing a pre-packaged pre-mixed amount of a polarizer-ready blend of unpolarized gas. Methods for producing the polarized gas can be carried out at the point of use site and the production run according to patient load. Other methods consider the patient load and automatically schedule the hyperpolarizer to yield the desired polarized gas doses to support the patient and/or MRI/NMR equipment schedule.

Abstract: MR imaging with gradient oscillations that are essentially at the same frequency to reduce off-resonance effects. Frequencies that are sufficiently close to each other to reduce such effects compared with known approaches are considered essentially the same frequency.

Abstract: A hybrid imaging technique, applicable to at least magnetic resonance imaging with generalized excitation profiles, addresses the problem of visualizing spatial encoding. The invention is an improvement on both the multi-slice and the Fourier encoding techniques, each of which is a special case representing an extreme of the range of allowable values to the number of phase-encoding steps. Therefore, use of values for this parameter in between these two ends achieves a new hybrid technique having varying degrees of similarity to both known techniques. The inventive technique can be close to non-redundant if implemented properly. Comparison to images to those from conventional Fourier encoding is favorable. The invention is also applicable to many other imaging applications such as in magnetic resonance angiography.

Abstract: A method and apparatus (10) for detecting and measuring the amount of crude oil in underground rock formations. EPR measurements are used to calculate the amount of crude oil, and may be calibrated to determine the particular type of crude oil. These measurements may be used in conjunction with NMR measurements, to provide accurate estimations of pore size and permeability.

Abstract: In a method and apparatus for magnetic resonance imaging with adherence to SAR limit values, a patient is subjected to a radio-frequency pulse sequence via at least one transmission antenna and the magnetic resonance signals that are produced are acquired in a spatially resolved manner via at least one reception antenna and are further-processed for producing magnetic resonance images or spectra, with current SAR values, determined before the implementation of the measurement on the basis of patient data and the position of the patient relative to the transmission antenna for planned parameters of the measurement, being modified as warranted until the current SAR values lie within the SAR limit values. The determination of the current SAR values ensues by comparing the current measurement situation to pre-defined measurement situations stored in a data bank for which pre-calculated SAR values are stored.

Abstract: In a method for magnetic resonance imaging with adherence to SAR limit values, a patient is charged with a radio-frequency pulse sequence via at least one transmission antenna for the implementation of a measurement in a magnetic resonance tomography apparatus, and the magnetic resonance signals that are produced are acquired in a spatially resolved manner via at least one reception antenna and are further-processed for producing magnetic resonance images or spectra. SAR values are determined before the implementation of the measurement on the basis of patient data and the position of the patient relative to the transmission antenna for planned parameters of the measurement, and the parameters are modified as needed until the SAR values lie within the SAR limit values. The position of the patient relative to the transmission antenna is exactly determined by an imaging magnetic resonance pre-measurement.

Abstract: A method of nuclear quadrupole resonance testing a sample is disclosed in which the excitation applied to the sample is arranged so that phase and amplitude information may be obtained from the response signal, and in which the signal is resolved into two components. Particularly if a parameter such as radio-frequency field strength varies with position, this may give an indication of the distribution of nuclei in the sample, preferably from the phase of the response signal. Positional information can also be obtained by measuring from two or more reference points. This may be employed in imaging. The phase information may be employed to improve the signal to noise ratio obtainable in other methods where only amplitude information was previously available, for example in distinguishing genuine NQR response signals from spurious signals.

Abstract: Variations in spatial phase distribution due to static magnetic field changes are corrected based on phase variations at points, specifically, at three points or a plurality of points selected by ROI, in an area where no temperature change is encountered. And a temperature distribution image is determined by using a spatial phase distribution reflecting only temperature changes after the correction, thereby high-accuracy temperature distribution image information is provided.

Abstract: A magnetic resonance apparatus has a controllable device with which at least a part of the magnetic resonance apparatus can be fixed in a first control statue and with which the part can be held isolated with respect to mechanical oscillations in a second control statue.

Abstract: The invention relates to a method of determining the spatial distribution of magnetic particles in an examination zone. According to this method a spatially inhomogeneous magnetic field is generated which includes at least one zone (301) in which the magnetization of the particles is in a non-saturated state whereas the particles in the remaining zone are in a saturated state. Shifting this zone within the examination zone produces a change of the magnetization which can be externally detected and contains information concerning the spatial distribution of the magnetic particles in the examination zone.

Abstract: Microcoil designs are provided that enable unique RF response Field profiles that are particularly useful in MRI imaging procedures, particularly where fields of view outside of the medical device are desirable. These devices are particulatly for use within an organism, the device comprising an element having at least one RF receiver, the coils of said microcoils defining a cross-section that lies in a plane oriented at 0 to 90 (or 0 to 80) degrees to the longest axis of the device. Another way of describing the device is as a device for use in an organism, the device comprising an element having at least one wound microcoil with at least three windings on the microcoil. Each winding has an aspect ratio of greater than one. The aspect ratio of each winding is measured as the ratio of longest to shortest dimension in a cross section situated approximately transverse to the winding axis of the coil windings, the winding axis also being transverse to the longest axis of said device.

Abstract: The invention relates to an imaging method. Layer or volume areas are selected by radiating high-frequency pulses and applying at least one magnetic potential field. Nuclear magnetic resonances are excited and are detected as measuring signals in said areas. According to the invention, the method is carried out in such a way that different layer or volume areas are successively selected and the corresponding measuring signals are detected by means of the magnetic potential field and that layer or volume images of the individual layer or volume areas are produced after the measuring signals for the different layer or volume areas have been detected.

Abstract: A method for determining petrophysical properties of geological structures using nuclear magnetic resonance utilizes a well logging apparatus and estimates resistivity in the formation surrounding a borehole by measuring current field strength and distribution.

Abstract: A device for measuring the filling level of a medium—for example hydrogen—in a storage container of a storage device—for example a tank system. To provide a simple and direct possible way of accurately determining the filling level of the storage container even without knowing the amount of medium already discharged or irrespective of uncontrollable losses, the device is designed as a measuring device for measuring the nuclear magnetic resonance of the medium located in the storage container. For this purpose, the device has a measuring head with, for example, a permanent magnet and a measuring coil, via which a static magnetic field and an electromagnetic alternating field are generated in the measuring head. The electromagnetic alternating field is generated in a transmitter, which is connected to the measuring head by a bridge circuit.

Abstract: The invention relates to an MR coil module for use in an MR imaging system for receiving and/or transmitting RF signals.

Abstract: A radio frequency (RF) coil assembly for a very high field Magnetic Resonance Imaging (MRI) system is provided. The RF coil assembly comprises a plurality of conductors arranged cylindrically and disposed about a patient bore tube of the MRI system. Each of the conductors is configured for the RF coil assembly to resonate at substantially high frequencies. Further, the RF coil assembly comprises a plurality of capacitive elements disposed between and connecting respective ends of the conductors and further disposed in a spaced-apart relationship with the patient bore tube. The capacitive elements are for electrically interconnecting the plurality of conductors at the respective ends of the conductors.

Abstract: The present invention provides methods and apparatus for determining flow velocity within a formation utilizing nuclear magnetic resonance (NMR) techniques in which the shape of the resonance region is restricted so that sensitivity to radial flow or vertical flow is obtained (or both when more than one NMR tool is used). Flow velocity using these NMR tools is determined using decay amplitude, frequency displacement or stimulated echoes (where the spins are stored along the magnetic field instead of the transverse plane to exploit echo decays and frequency displacements) based on the application of adiabatic pulses. Based on the described NMR measurement of flow velocity, additional wellbore parameters may be obtained such as a direct measurement of permeability, an assessment of drilling damage to the wellbore, formation pressure, invasion rate of the mud filtrate or the migration of fine mud particles during sampling operations.

Abstract: The present invention provides methods and apparatus for determining flow velocity within a formation utilizing nuclear magnetic resonance (NMR) techniques in which the shape of the resonance region is restricted so that sensitivity to radial flow or vertical flow is obtained (or both when more than one NMR tool is used). Flow velocity using these NMR tools is determined using decay amplitude, frequency displacement or stimulated echoes (where the spins are stored along the magnetic field instead of the transverse plane to exploit echo decays and frequency displacements) based on the application of adiabatic pulses. Based on the described NMR measurement of flow velocity, additional wellbore parameters may be obtained such as a direct measurement of permeability, an assessment of drilling damage to the wellbore, formation pressure, invasion rate of the mud filtrate or the migration of fine mud particles during sampling operations.

Abstract: The present invention provides methods and apparatus for determining flow velocity within a formation utilizing nuclear magnetic resonance (NMR) techniques in which the shape of the resonance region is restricted so that sensitivity to radial flow or vertical flow is obtained (or both when more than one NMR tool is used). Flow velocity using these NMR tools is determined using decay amplitude, frequency displacement or stimulated echoes (where the spins are stored along the magnetic field instead of the transverse plane to exploit echo decays and frequency displacements) based on the application of adiabatic pulses. Based on the described NMR measurement of flow velocity, additional wellbore parameters may be obtained such as a direct measurement of permeability, an assessment of drilling damage to the wellbore, formation pressure, invasion rate of the mud filtrate or the migration of fine mud particles during sampling operations.

Abstract: The present invention provides methods and apparatus for determining flow velocity within a formation utilizing nuclear magnetic resonance (NMR) techniques in which the shape of the resonance region is restricted so that sensitivity to radial flow or vertical flow is obtained (or both when more than one NMR tool is used). Flow velocity using these NMR tools is determined using decay amplitude, frequency displacement or stimulated echoes (where the spins are stored along the magnetic field instead of the transverse plane to exploit echo decays and frequency displacements) based on the application of adiabatic pulses. Based on the described NMR measurement of flow velocity, additional wellbore parameters may be obtained such as a direct measurement of permeability, an assessment of drilling damage to the wellbore, formation pressure, invasion rate of the mud filtrate or the migration of fine mud particles during sampling operations.

Abstract: A logging while drilling (LWD) and measuring while drilling (MWD) method and device are disclosed for reducing the sensitivity of NMR measurements to tool motions. The invention is based on NMR relaxation measurements determining longitudinal relaxation times T1 instead of the standard T2 measurements, and involves saturating a relatively wide sensitive region of the formation and processing NMR echo signals which originate approximately from the center of the sensitive region. In another aspect, the invention uses novel pulse sequences and processing algorithms to reduce the time for the relaxation measurement and to provide real-time transfer of data uphole.

Abstract: A system and methods for improving the vertical resolution of NMR logs based on data acquisition methods and signal processing techniques that need not apply Phase Alternated Pair Stacking (PAPS). The method is based on reducing the level of coherent non-formation signals, by estimating these signals and removing the estimates from the underlying NMR pulse echo trains. Once the estimated non-formation signal components have been removed, standard NMR processing methods are applied to derive petrophysical properties of the formation being investigated. In a preferred embodiment the NOPAPS method of this invention is practiced along with a data acquisition sequence, which can be used to further increase the logging speed of the tool or vertical resolution of the measurements.

Abstract: The invention is a method and apparatus for performing NMR measurements in MWD effective for large and small boreholes. The invention uses a magnet assembly to produce a generally oval static magnetic field. The invention also employs an antenna assembly comprised of a primary and secondary antenna to deliver a sequence of RF magnetic pulses. For small holes, the antenna assembly operates to substantially match the iso-lines of the static magnetic field within the rock formation during a transmission pulse. For large holes, the invention works in a side-looking mode and the antenna assembly operates both to match the iso-lines of the static magnetic field within the rock formation and to diminish the magnetic field within the borehole during a transmission pulse. The secondary antenna can also be used as a receiver of spin echo signals, or optionally, to make adjustments to the received signal.

Abstract: Method of detecting cracks in an object of an electrically conducting material that is covered by a non-conductive layer using a probe comprising a transmitter coil for inducing eddy currents in the object and a receiver coil comprising selecting a set of points of the object which are to be inspected; and which method further comprises for each point positioning the probe at the point, activating the transmitter coil to induce eddy currents in the object; creating a record of the signal provided by the receiver coil over a period of time; and examining the record and comparing it to reference records, wherein the presence or absence of a crack can be inferred from the comparison.

Abstract: A nuclear quadrupole resonance (NQR) method and probe for generating RF magnetic fields in different directions to distinguish NQR from acoustic ringing induced in a sample. Generally, an RF magnetic field is generated along an axis towards a sample to induce a resonance signal in the sample. The resonance signal includes NQR and acoustic ringing. The resonance signal is detected along the RF magnetic field axis. The acoustic ringing is detected along a direction orthogonal to the RF magnetic field axis. As a result, the NQR in the resonance signal can be distinguished from the acoustic ringing in the resonance signal.

Abstract: A transverse dipole NMR tool includes a non-conductive permanent magnet made of electrically conductive material such as SmCo. The concentration of SmCo is selected to be at a level low enough to prevent the formation of an electrically conductive path through the magnet. Disposed between the grains of conductive magnet material may be either a ferrite (to increase the remnant magnetization and coercive force) or an inert material. There is a tradeoff between increasing the grain size of the conductive material and the increased intragranular power dissipation. The volume fraction of the conductive material may be increased to a level somewhat higher than a theoretical percolation limit for packed materials; due to randomness in the grain distribution, as long as domains where the percolation limit is exceeded are separate, no conductive path through the magnet results.

Abstract: A system and method for calculating the lateral velocity of a rotating drilling tool within a borehole, the system comprising: a pair of accelerometers placed oppositely across the drilling tool axis of rotation and two magnetometers.

Abstract: The invention relates to a method of and a device for exciting the nuclear magnetization in a limited volume of an object to be examined, utilizing a microcoil (L) which is present in the volume and is attached, for example, to an interventional instrument during the formation of a magnetic resonance image of the object to be examined. The excitation of the nuclear magnetization is performed by at least one RF pulse whose frequency spectrum does not overlap the range of the spin resonance spectrum, so that no nuclear magnetization is excited outside the close range of the microcoil in the object to be examined. The microcoil, however, is provided with an active or passive circuit (for example, it is wired together with at least one capacitance (C) and a non-linear component (D1, D2) so as to form a non-linear resonant circuit) which locally generates an RF signal from the RF pulse.

Abstract: An MRI apparatus and method useful for both industrial applications and medical applications is provided. The apparatus and procedures are capable of estimating the value of a continuous property, such as concentration, viscosity or the like by interpolating or extrapolating from a model derived from training sets of data representing measurements of samples with known properties. A number of techniques are provided for objectifying the analysis. Cluster analysis techniques can be used to supplement, assist or replace subjective judgments by trained operators. Calculations or judgments regarding similarity can be made with respect to stored libraries of signatures, particularly where the library of stored signatures is obtained objectively, e.g., using cluster analysis, standardization and calibration. The signatures can be expanded signatures which include non-MR as well as MR data.

Abstract: A device is described which permits the acquisition of Electron Paramagnetic Resonance Images without employing additional hardware for generation of magnetic field gradients. It employs the inherent gradient in the modulation field, operating with high amplitude modulator.

Abstract: A method and apparatus for screening samples to determine which samples include a target material. Generally, the samples are pre-screened to determine which of the samples have a piezoelectric resonance when irradiated with an electric field, to thereby indicate the presence of the target material. The samples that have the piezoelectric resonance are then further screened by a different process to confirm the presence of the target material. For example, samples that have the piezoelectric resonance are further screened for a specific nuclear quadrupole resonance (NQR), a specific nuclear magnetic resonance (NMR) or a specific visual characteristic, to confirm the presence of the target material in the sample. The apparatus and method can be used, for example, to search luggage at ports of entry for the presence of cocaine hydrochloride or heroin hydrochloride.

Abstract: A method and an apparatus for obtaining NMR measurements are disclosed. An NMR measurement apparatus, the measured sample, or both elements may be subjected to motion during the measurement. The envelope of an RF carrier signal is modulated according to an envelope to generate a first sequence of RF pulses. The envelope, the phase of the RF signal, and/or a static magnetic field may be varied during the radiation of the first sequence to substantially saturate a first region of the sample. The first sequence may include additional RF refocusing pulses that, when coupled with movement of the NMR measurement apparatus or sample, may also be used to substantially saturate the first region. A second sequence of RF pulses is radiated to establish a resonance region within the first region and measure an attribute of the sample.

Abstract: The invention relates to a method for determining the degree of polarization (P) of a nuclear spin polarized gas, in particular 3He, 129Xe, in which the nuclear spin polarized gas is placed in a container, comprising determining the magnetic field Bd of the pola gas by measuring the magnetic dipole field emerging therefrom and then determining from Bd the degree of polarization of the gas.

Abstract: An apparatus for and a method of Nuclear Quadrupole Resonance testing a sample in the presence of interference are disclosed. The apparatus comprises excitation applying means for applying excitation, a first antenna for detecting a response to the excitation together with the interference, and a second antenna for detecting the interference, the first and second antennas being arranged such that a signal commonly detected in the two antennas is attenuated relative to a signal that is detected by only one of the antennas. The apparatus may provide suppression of interference.

Abstract: An NMR imaging process utilizes both driven equilibrium and fast-spin echo techniques to acquire image data. The fast-spin echo technique is a multi-echo imaging sequence, where a 90-degree RF pulse applied at the center of any echo turns the magnetization back in the direction of the static magnetic field. Within a short waiting time after that pulse, the spins are ready to be excited again. The sequence follows a first 90-degree RF pulse by a series of n 180-degree RF pulses, followed by n echoes. A second 90-degree RF pulse applied to the nth echo returns the magnetization. A multiple single-slice mode is utilized to acquire individual slice images one at a time. A continuous single-slice mode is utilized to acquire individual slice images automatically in sequence over the region of interest. In either mode, adjacent slices can be made to overlap to a degree ranging from 0% to 100%.

Abstract: Disclosed are a method of measuring ESR in a sample located outside a resonator using the B1 leaking to the exterior from the end of the resonator; and an ESR device comprised of at least a resonator capable of applying a B1 leaking from the end of the resonator to a sample located outside the resonator, and a magnet located on the resonator side of a plane containing the end of the resonator that is capable of applying a B0 and a modulation field. These inventions enable ESR measurement of the interior of large samples.

Abstract: The present invention is directed to a procedure for recycling used gasses and to devices that can be use to accomplish this recycling.

Abstract: A diode laser-pumped magnetometer includes a diode laser that emits a polarized pumping laser beam with resonant optical radiation; and a K-cell through which a magnetic field is manifested from an independent source, the K-cell containing atoms with a dipole experiencing a torque due to the magnetic field. The atoms are excited by the resonant optical radiation of the pumping laser beam and periodically emitting a response radiation as they return to ground state such that the response radiation includes photons that indicate one unit of angular momentum indicative of the torque due to the magnetic field. Finally, a photodetector serves as a means for measuring the response radiation of the K-cell to indicate thereby a measure of the magnetic field in the K-cell from the independent magnetic source.

Abstract: A device is described which permits the acquisition of Electron Paramagnetic Resonance Images without employing additional hardware for generation of magnetic field gradients. It incorporates a module for translation of the bridge-circulator-resonator-detector assembly in order to locate the resonator at an optimal off-center position in the magnet and employs the inherent gradient in the magnetic field, permitting operation with gradients of 5 T m−1 or higher, in continuous wave or pulsed mode.

Abstract: Nuclear magnetic resonance measurements on a fluid in a rock and methods of analyzing nuclear magnetic resonance data are described. At least one nuclear magnetic resonance measurement is performed, and nuclear magnetic resonance data from each of the measurements are acquired. The data are compressed and analyzed to extract information about the fluid in the rock.

Abstract: A pulsed NMR tool has a magnet arrangement that is used to generate a static magnetic field having a substantially uniform field strength in a region of the formation surrounding the borehole. An RF coil is used to produce pulsed RF fields orthogonal to the static field in the region of examination. The nuclear spins in the formation align themselves along the externally applied static magnetic field. A pulsed RF field is applied to tip the spins by 90°, resulting in a precession of the spins. The tipping pulse is followed by a series of refocusing pulses and the resulting series of pulse echoes is detected. Motion sensors on the tool produce signals indicative of the motion of the tool and a processor on the tool controls the timing of the tipping pulse to coincide with substantially zero motion of the tool in an axial direction or one perpendicular to the axial direction. A Kalman filter or other predictive filter is used to predict the desirable pulse triggering times.

Abstract: In a method and apparatus for obtaining magnetic resonance data from water-containing substance, nuclear spins are excited in the substance in the presence of a homogenous static magnetic field, while an electrical current is flowing in the subject. The electrical current flowing in the subject shortens the spin-spin relaxation time and the spin-lattice relaxation time, and lengthens the apparent diffusion coefficient of the substance.

Abstract: An NMR device includes an NMR coil, and a sample flow path connected to a sample supply source and passing through the NMR coil. The NMR device can carry out an on-line measurement so that a portion passing through the NMR coil of the sample flow path functions as an NMR probe for measurement. A filler for absorbing a sample is provided at a position of the NMR probe in the sample flow path, and the NMR measurement is carried out in a state where the sample is absorbed by the filler. Thus, when the measurement is carried out, the sample is retained accurately at the NMR coil position while a very small quantity of sample is being concentrated.