Abstract: A wideband NQR detection system includes an RF coil system having a plurality of RF coils that can be used to excite and detect a plurality of NQR spectral lines at the same time. Each of the plurality of RF coils is shaped and configured so as to generate, when driven by RF pulses, RF fields that are substantially de-coupled, for example by being mutually orthogonal. In this way, each coil can function independently, without affecting the operation of any other coil. The RF pulses used to excite NQR resonances can be prepared digitally, as a composite waveform formed as a superposition of individual waveforms, each optimally tailored to excite one spectral line. The wideband NQR detection system also includes a wideband transmitter for generating and transmitting RF pulses, and a wideband receiver for receiving the NQR response signals detected by the coils.

Abstract: A probehead for an electron spin resonance (ESR) dosimeter comprises a resonator and an insert extending into the resonator. The insert has a guide channel for bringing a sample into the resonator. The sample comprises a dosimeter substance. The guide channel is configured for receiving and guiding a test strip. The insert is provided with a first machine-readable code imprint. The insert is provided with at least one reference sample. A pressurized air unit is provided for blowing the sample out of the resonator after completion of a measurement. The insert has an opening on an upper side of the resonator. The opening is openly accessible for manually inserting dosimeter pills thereinto. The insert, further, is provided on the upper side with a pressurized air connector. The pressurized air connector is connected to an orifice via a pressurized air channel within the insert. The orifice is located within a lower, otherwise closed bottom of the guide channel.

Abstract: A detector of near-infrared light includes a light receiving device having a perovskite-type composite oxide expressed by a general formula of La1−xPrxCrO3 (where 0<x<1) and magnetization measuring means for measuring an increase in magnetization in the composite oxide of the light receiving device when the light receiving device is irradiated with near-infrared light at room temperature.

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: Signal recovery in functional magnetic resonance imaging (fMRI) is provided by generating a single excitation pulse and exciting a target region of a subject with the generated excitation pulse. A first image is obtained using a first partial k-space frame of the target region. A compensation pulse is generated and the target region excited with the compensation pulse. A second, compensated, image is obtained subsequent to the excitation by the compensation pulse using a second partial k-space frame of the target region. The first and second images are combined to form a combined image of the target region. The first and second obtaining steps are carried out sequentially during a single quadratic excitation pulse.

Abstract: In a scanning microwave microscope including a microwave resonator, an exciting unit for exciting the microwave resonator, a first detecting unit for detecting a first detection amount relating to a resonant state of the microwave resonator, a sharp end coupled to a center conductor of the microwave resonator, and a display unit for displaying the first detection amount while a sample is scanned by the sharp end, a distance changing unit causes a differential change in a distance between the sharp end and the sample. A second detecting unit detects a second detection amount relating to a change of the first detection amount. A control unit controls the distance between the sharp end and the sample in accordance with the second detection amount, so that an average value of the distance between the sharp end and the sample is brought close to a definite value.

Abstract: A resonator apparatus and a method for electron spin resonance (ESR) measurements are disclosed. The resonator apparatus comprises a dielectric resonator and a sample vessel extending through the resonator. The sample vessel is configured as one single flexible tube. Means are provided for conveying a liquid sample substance through the flexible tube. According to the method a liquid sample substance is guided through the sample vessel, wherein the sample substance is gated by cyclically conveying and stopping, resp., a flow of the sample substance. A measurement is conducted within the resonator when the flow of sample substance is stopped.

Abstract: A radiofrequency (RF) coil design, suitable for detecting time domain electron paramagnetic resonance (EPR) responses from spin probes after pulsed excitation using radiofrequency irradiation (60-400 MHz), is configured in an array of numerous surface coils of appropriate diameters connected in a parallel or axial configuration with appropriate spacing between individual surface coils to form a volume type resonator.

Abstract: A uniform-field resonator includes a central cavity section having a cross-section which is set to the cutoff frequency for a particular microwave propagation mode and a pair of end sections which enclose the cavity to form a resonator in which the field is substantially uniform along the entire length of the central cavity—regardless of its length. A number of end section design strategies and resulting structures are described for supporting the uniform-field mode of operation in the central cavity section.

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: 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: A method and an apparatus for investigating the imperishability of n liquid foodstuffs using electron spin resonance (ESR) exposes samples of the foodstuffs to an elevated temperature for an extended time-period. At predetermined intervals during the period, the intensity of an ESR signal of each sample is measured and plotted vs. time in a diagram for that sample. The time of a superproportional increase in intensity is detected for each foodstuff. The number n of different foodstuffs is determined by dividing the predetermined interval by the measurement time. The n samples are investigated simultaneously by sequentially cycling the n samples through a common sample vessel. Each time, the intensity of the ESR signal of the sample is measured and then plotted in a diagram unique to that foodstuff. The sequence of foodstuffs are cycled through the sample vessel until a predetermined number m of measuring points per foodstuff has been attained.

Abstract: A junction field effect transistor (JFET) RF oscillator-detector circuit generates an RF signal for an apparatus for conducting electrical measurements of particles contained in a carrier fluid passing through an aperture in a cytometer flow cell. The JFET oscillator includes a plurality of parallel-coupled JFETs having respectively different VDS vs. IDS characteristics, that are biased to operate at square law detection regions of their respective VDS vs. IDS characteristics. One JFET operates in Class C mode, while the other operates in Class AB mode. An RF resonant circuit is electrically coupled to the JFETs and to the measurement cell, and is operative to establish the frequency of an RF field applied to the measurement cell. An RF load change detection circuit is coupled to the RF resonator circuit and is operative to detect an RF load change associated with a modification of the RF field as a result of a particle within the measurement cell aperture.

Abstract: A bicycle computer includes a base member structured to mount to a structural member of a bicycle. A cover having an inner surface is swingably coupled to the base so that the inner surface may be moved from a closed position where the inner surface faces the base member to an open position where the inner surface may be viewed or accessed by a user.

Abstract: A safety system for a gas process or facility for measuring the concentration of a specified gas in an area or chamber and determining whether it is safe to allow access to such area or chamber. In particular, the safety system is adapted for use in a gas sterilization facility having one or more sterilization chambers, wherein the safety system measures the concentration of the sterilizing gas and unlocks the door of the sterilization chamber if the level of the sterilizing gas in the sterilization chamber is below a predetermined limit. The safety system further limits access to the sterilization chamber after a predetermined period of time if the door of the sterilization chamber is not opened due to the possible continued desorption of the sterilizing gas from the articles into the sterilization chamber.

Abstract: A preferred embodiment of the present invention includes a system for detecting a presence of a macromolecule having one or more resonant frequencies. The system includes a pulse generator (a T-wave generator in the most preferred embodiment) for generating a detection profile having a detection set of T-waves and applying the detection profile to a sample including the macromolecule, at least one T-wave having a center frequency substantially centered on one of the resonant frequencies of the macromolecule, a detector for receiving the detection profile after the application of the detection profile to the sample, an analyzer, coupled to the detector, for determining a T-wave absorption profile by identifying which T-waves of the set of T-waves have been wholly or partially absorbed by the sample and to subsequently identify the macromolecule by use of the absorption profile.

Abstract: In nuclear magnetic resonance imaging of the human brain or the like, multiple quantum coherences, such as intermolecular double quantum coherence (iDQC) between water molecules, are used for soft tissue contrast. A group of pulse sequences are used in which, (a) The standard &bgr;=&pgr;/2 pulse in the original CRAZED sequence is replaced with a &pgr;/3 pulse. The maximum signal derived from iDQCs is increased by a factor of 3{square root}{square root over (3)}/4. (b) The position of the acquisition window is adjusted, and a large acquisition window (small bandwidth) is used to sample a broad range of time-domain signals. (c) Receiver dynamic range is optimized. (d) A two-step phase cycle scheme for iDQC-encode gradients is designed to remove additional undesired coherence pathways.

Abstract: A junction field effect transistor (JFET) RF oscillator-detector circuit generates an RF signal for an apparatus for conducting electrical measurements of particles contained in a carrier fluid passing through an aperture in a cytometer flow cell. The JFET oscillator includes a plurality of parallel-coupled JFETs having respectively different VDS vs. IDS characteristics, that are biased to operate at square law detection regions of their respective VDS vs. IDS characteristics. One JFET operates in Class C mode, while the other operates in Class AB mode. An RF resonant circuit is electrically coupled to the JFETs and to the measurement cell, and is operative to establish the frequency of an RF field applied to the measurement cell. An RF load change detection circuit is coupled to the RF resonator circuit and is operative to detect an RF load change associated with a modification of the RF field as a result of a particle within the measurement cell aperture.

Abstract: A variable-coupling quasioptical electron paramagnetic resonance apparatus. In one embodiment, the variable-coupling quasioptical electron paramagnetic resonance apparatus includes a variable coupling quasioptical resonance cavity constructed from two back-to-back Fabry-Perot interferometers. One Fabry-Perot interferometer is formed from two partially reflecting mirrors. The second Fabry-Perot interferometer is an interferometer formed from one of the partially reflecting mirrors and a back mirror. A sample to be studied is placed within the cavity adjacent the partially reflecting mirrors and between one of the partially reflecting mirrors and the back mirror. The relative spacing of the partially reflecting mirrors and the back mirror is adjustable. With this arrangement, the interferometer can be made to act as a single mirror with variable reflectivity, thereby permitting incident radiation reaching the sample to be varied precisely and continuously.

Abstract: An MRI system performs a calibration prescan in which NMR projection signals are produced using a calibration pulse sequence. The readout gradient employed during the acquisition of each NMR projection signal is rotated during the signal sampling such that the projection angle changes during the acquisition. The center of the field of view is weighted more heavily in the calculation of the optimal RF transmit power to provide a more accurate setting when using local coils.

Abstract: A small-sized, inexpensive automatic sample exchange device for use with an NMR spectrometer. The exchange device has a mechanism acting to convey sample tubes and also to grip them. The exchange device includes a disk plate located just above a sample inlet hole formed in the spectrometer. The disk plate has a fringe portion provided with a recess. The sample tubes are inserted into a given number of sleeves, which are mounted to a turntable and to the disk plate. An ultrasonic motor rotates the turntable, the disk plate, and the sleeves integrally. When the sleeves register with the recess in the disk plate, the fringe portion of the disk plate does not protrude into holes formed in the sleeves. When the sleeves do not register with the recess, the fringe portion protrude into the holes in the sleeves, thus gripping the sample tubes.

Abstract: A magnetic resonance imaging method comprises exciting spins in an investigation volume via a radio frequency pulse and the signal produced thereby is subsequently read-out after appropriate spatial encoding following a short echo time te. Repetition of the sequence required for spatial encoding occurs in a time interval tr under appropriate variation of the spatially encoding gradient. The radio frequency pulse utilized for excitation has a short time duration and therefore a large excitation band width so that a projection image through a thick projection slice is produced under application of no slice selection gradient or with only a weak slice selection gradient. The time interval tr is sufficiently minimized that the image recording time required for recording of an image lies in the range of one EKG cycle or below. This process of recording a projection image is continuously repeated and a contrast medium bolus administered during the course of this sequential recording.

Abstract: A ferromagnetic resonance measuring cavity resonator comprises a cavity resonator having a cavity formed by a side wall. The side wall is provided with an input/output hole and a through-hole. A ferromagnetic plate provided with a through-hole is mounted on the outside surface of the side wall such that the two through-holes are aligned. A wafer specimen is pressed against the ferromagnetic plate to face the through-hole. When microwaves are introduced into the cavity resonator, ferromagnetic resonance takes place based on the static magnetic field applied to the wafer specimen and the microwaves. As a result, a ferromagnetic resonance signal is detected via the input/output hole.

Abstract: A magnetic probe (1) for use with a magnetic resonance imaging apparatus comprises an electron spin resonance (ESR) magnetometer. The position of the probe (1) tracked by measuring the resonant frequency of an ESR sample (32) in the probe. The resonant frequency is measured in the presence of a gradient sequence which employs three orthogonal, linear gradients. By determining the resonant frequency of the ESR sample in the presence of each of the gradients, the position of the probe can be determined. The probe may be placed on or in an object, and the position of the probe may be displayed on a desired magnetic resonance image of the object.

Abstract: The invention provides apparatus and methods for measuring oxygen tensions in biological systems utilizing physiologically acceptable paramagnetic material, such as India ink or carbon black, and electron paramagnetic resonance (EPR) oximetry. India ink is introduced to the biological system and exposed to a magnetic field and an electromagnetic field in the 1-2 GHz range. The EPR spectra is then measured at the biological system to determine oxygen concentration. The EPR spectra is determined by an EPR spectrometer that adjusts the resonator to a single resonator frequency to compensate for movements of the biological system, such as a human or animal. The biological system can also include other in vivo tissues, cells, and cell cultures to directly measure pO.sub.2 non-destructively.

Abstract: Quantitative determination and evaluation of the flavor stability of fermented alcoholic beverages are performed by measuring the changes of the amount of spin adduct from the formation behavior of active oxygen with passage of time using an ESR apparatus and either determining the value on the time axis of the inflection point of changes of the amounts of spin adduct (defined as the active oxygen formation lag time) or determining the amount of spin adduct after a predetermined time has elapsed after the start of measurement (defined as the active oxygen formation activity). The longer the active oxygen formation lag time or the lower the active oxygen formation activity, the greater the oxygen resistance of the fermented alcoholic beverage, thus making it possible to evaluate that fermented alcoholic beverage as having good flavor stability.

Abstract: An apparatus for use in electron paramagnetic spectroscopy having a resonant structure with one or more dielectric resonators, the resonant frequency of which may be varied by varying the distance between the dielectric resonators, the coupling between the coupler and resonant structure may be varied by a remote coupling matching device without changing the resonant frequency of the resonant structure.

Abstract: A resonator structure including a first resonator having a first resonator loop formed by a hollow channel with conductive walls and a second resonator having a second resonator loop formed by a hollow channel with conductive walls. The first resonator loop and the second resonator loop intersect so that the first and second resonator loops are substantially shielded to prevent coupling of high frequency energy between the first and second resonator loops. A sample is placed in a space defined by the intersection of the first and second resonator loops. High frequency energy is applied to the first resonator. The angle at which the second resonator loop intersects the first resonator loop is selected to substantially decouple the first resonator from the second resonator. A detector circuit detects the high frequency energy in the second resonator loop and supplies the detected signal for subsequent analysis.

Abstract: Disclosed is a method of determining two-dimensional nuclear- or rotating frame-Overhauser effect spectroscopy intensities for a ligand-enzyme system having flexible active cites, wherein the ligand-enzyme system has at least 3 conformational states. The first step is inputing data into a modeling computer of coordinates for each molecule on the enzyme and ligand, kinetic data, correlation times, and concentrations of ligand and enzyme. Next, a K matrix is created from the kinetic data, and an an R matrix is derived from the correlation times and the coordinates. A dynamic matrix D is created by summing the K and R matrices. This D matrix is symmetrized and diagonalized. Spectroscopy intensities are then derived from the symmetrized and diagonalized D matrix.

Abstract: A process for frequency tuning microwave bridges and a device for practicing such a process. The process is characterized in that it consists in subjecting a resonator (3) to the radiation delivered by a secondary microwave source (10) sweeping a wide band of frequencies comprising particularly the frequency (F) of radiation delivered by the principal microwave source (1). The radiation reflected by the resonator (3) is displayed and the relative positions are marked along the frequency spectrum, of the frequency (F) and of the frequency of resonance (Fr) of the resonator (3). The frequency (F) of radiation delivered by the principal microwave source (1) is varied while controlling in real time the effect of this variation on the relative positions of the frequencies (F and Fr).

Abstract: A transducer for Overhauser magnetic resonance imaging comprises a cylindrical NMR coil 11 and a two part VHF applicator 12, 13. The applicator and coil are arranged such that the electric field provided by the applicator in use is substantially perpendicular to the coil wires. The VHF applicator is shaped to give a helical field in the region filled by the RF coil, and the RF coil is arranged to be a helix of the opposite handedness. The applicator can comprise a number of similar elements having an electromagnetic resonance mode whose magnetic fled couple to the imaging volume. The elements can be arranged in spirals to form an electric periodic structure.

Abstract: An apparatus for use in electron paramagnetic spectroscopy having a resonant structure with one or more dielectric resonators, the resonant frequency of which may be varied by varying the distance between the dielectric resonators, the coupling between the coupler and resonant structure may be varied by a remote coupling matching device without changing the resonant frequency of the resonant structure.

Abstract: The invention provides a cavity resonator for an electron spin resonance device in which modulation coils for generating a modulation magnetic field to be applied to a sample in the cavity resonator are arranged at an exterior of the cavity resonator. The cavity resonator comprises a body being rectangular-defined by predetermined length, width and height. The body has a pair of side walls being vertical to the modulation magnetic field. The side wall respectively have at least thin portions of a thickness being nearly equal to or less than a skin depth of a skin effect appearing at the side walls. The modulation coils are arranged on the thin portions so as to have the modulation magnetic field be transmitted through the thin portions into the interior of the cavity resonator. Alternatively, it is possible that inner walls of the body are overlaid with metallic foils having at least sufficiently smaller thickness than a skin depth of a skin effect appearing at the walls.

Abstract: A microwave spectrometer includes a sensing chamber into which is introduced a gas or constituent to be analyzed. Microwave radiation is introduced into the chamber and any of the chamber resonant frequency, the microwave frequency, and the center frequency of the absorption peak are varied independently. The resultant variation in intensity of the microwave radiation in the chamber is monitored to determine the concentration of the gas within said chamber. The spectrometer may include a frequency measuring and reference system for measuring the resonant frequency of the chamber.

Abstract: A method and apparatus for detecting spin transitions for a paramagnetic substance that are induced in the absence of a magnetic field. The method includes the steps of placing a substance under investigation in a high magnetic field. The magnetic field is then rapidly turned off and then reenergized. An ESR signal obtained after the magnetic field is reenergized is used as a baseline. This process is then repeated except that when the magnetic field strength is reduced to zero, the substance is exposed to radio frequency (rf) electromagnetic energy. Any spin transitions induced in the substance by absorption of the rf energy are detected by comparing the resulting ESR signal, detected when the magnetic is reenergized, to the baseline ESR signal.

Abstract: A pulsed electron spin resonance spectrometer is provided with a first microwave oscillator for generating measuring signals of a high microwave frequency of about 80 GHz or above. A second microwave oscillator generates auxiliary signals at a lower microwave frequency of about 12 GHz or below. A first mixer generates mixed signals by mixing a measuring signal with an auxiliary signal. A pulse shaping channel generates pulsed mixed signals having a pulse length sufficient for carrying out pulsed electron spin resonance experiments. Moreover, a measuring resonator is provided to which the pulsed mixed signals are applied. A second mixer generates an output signals of a lower microwave frequency by mixing the mixed signal outputted from the measuring resonator with a signal being derived from the first microwave oscillator. A pulse shaping channel is switched between the second microwave oscillator and the first mixer.

Abstract: A probe for detecting and dosing molecular oxygen by the electronic paramagnetic resonance spectrometry of a sample of lithium phthalocyanine in contact with the atmosphere to be tested. The probe includes a fixed glass tube with the shape of a hairpin, traversed by a flow of an atmosphere to be tested. The top of the tube contains a chamber with porous walls traversed by the flow of the atmosphere to be tested. The chamber contains the phthalocyanine sample and is surrounded by the spires of an electronic resonance detector trip coil. A movable magnet surrounds the tube and is provided with windings to create a continuous field for polarizing the phthalocyanine sample.

Abstract: An EPR imager and spectrometer includes pulse generating system for generating broadband pulses having an RF carrier frequency that is not highly absorbed by biological samples. The pulse generating system includes up and down chirp convertors for frequency modulating a carrier frequency pulse and compressing the frequency modulated pulse to form a broadband excitation pulse of high energy. Such a machine could form the basis of a clinical imaging device capable of high sensitivity to free radical species in human patients.

Abstract: The invention provides apparatus and methods for measuring oxygen tensions in biological systems utilizing physiologically acceptable paramagnetic material, such as India ink or carbon black, and electron paramagnetic resonance (EPR) oximetry. India ink is introduced to the biological system and exposed to a magnetic field and an electromagnetic field in the 1-2 GHz range. The EPR spectra is then measured at the biological system to determine oxygen concentration. The EPR spectra is determined by an EPR spectrometer that adjusts the resonator to a single resonator frequency to compensate for movements of the biological system, such as a human or animal. The biological system can also include other in vivo tissues, cells, and cell cultures to directly measure pO.sub.2 non-destructively.

Abstract: An electron spin resonator (ESR) is used to compensate for temporally varying instabilities in the main magnetic field B.sub.o of a nuclear magnetic resonance imaging apparatus during the derivation of NMR imaging data from an object being imaged. The ESR monitor is placed at a point outside but close to the object such that the ESR monitor is affected by the temporally varying fields. Variances across the ESR caused by gradient fields are compensated for such that the output of the ESR is independent of the strength of the gradient fields. The ESR output is used to reduce the influence of said instabilities on the imaging data.

Abstract: In a fixed polarized magnetic field generated by permanent magnets 10, a cylindrical cavity resonator 12 and a coil 14 modulating the magnetic field are provided. A micro-wave f generated from a micro-wave oscillator 16 is supplied through an isolator 18 and a subsequent attenuator 20 and then a circulator 24 to the cavity resonator. The oscillation output of a modulating frequency oscillator 42 is supplied to the coil 14. A movable end plate 60 is moved by a driving feature 58 to vary the resonance frequency f.sub.0 for a detection thereof and a subsequent negative feed back to a micro-wave oscillator 16 through a circuit comprising a low frequency amplifier 48, a phase detector 50, a low frequency oscillator 54, a phase shifter 56 and a micro-wave oscillator power source 52 thereby the micro-wave frequency f is so swept as to be maintained to be equal to the resonance frequency f.sub.0.

Abstract: A method and a device for tuning a HF source, which oscillates at a basic frequency, to a narrow-band component, in particular for tuning a microwave source 61 of an electron spin resonance spectrometer to a resonator 62. In order to mutually tune the resonance frequency F.sub.R of the resonator 62 and the basic frequency f.sub.O of the source 61, the output signal of the source 61 is mixed in a mixer 64 with a sweep signal of an oscillator 65. The behavior of the resonator 62 is observed on a visual display unit 67, via a detector 68, in the form of what is called a "mode curve", and the source 61 is re-tuned so that two dips in the mode curve are brought into coincidence.

Abstract: The invention provides an electron spin resonance device in which a measuring sample is arranged in a cavity resonator in a polarization magnetic field for a receipt of a predetermined microwave power and a subsequent resonance signal detection from said sample. A microwave signal amplifier is arranged on a prestage of a microwave detection circuit for an addition of a part of an output from a microwave oscillator at an input terminal of said amplifier so as to accomplish a balanced cancellation of a microwave reflective power from said cavity resonator.

Abstract: A dielectric probe, of the type in which an electromagnetic wave is reflected from a dielectric/magnetic structure and spectrum analyzed, further includes a coil for applying a magnetic field to the structure as the wave is being reflected. Information about the intrinsic electromagnetic properties, integrity and structure of the material is obtained by comparing the reflected spectra for both the magnetic field on and off conditions.

Abstract: An EPR imager and spectrometer includes pulse generating system for generating broadband pulses having an RF carrier frequency that is not highly absorbed by biological samples. The pulse generating system includes up and down chirp convertors for frequency modulating a carrier frequency pulse and compressing the frequency modulated pulse to form a broadband excitation pulse of high energy. Such a machine could form the basis of a clinical imaging device capable of high sensitivity to free radical species in human patients.

Abstract: A resonator arrangement 10 serves for electron spin resonance spectroscopy. It comprises an upper carrier plate 30, a long center portion 32, 33, 40, 41 and a lower resonator section 45, 46, 47. In the area of the center portion 32, 33, 40, 41, there is provided at least one separating plane 50, 51 along which the resonator arrangement 10 can be divided into an upper part 52 and a lower part 52, it being possible to connect a plurality of different lower parts 53 to one and the same upper part 52.

Abstract: Disclosed herein is a measuring apparatus and a measuring method which can measure a physical property value such as an oxygen content or thermal conductivity of a sample material such as an aluminum nitride sintered body with high accuracy, over the entire material in a short time. A microwave oscillation source generates microwaves. A sample material to be evaluated, such as an aluminum nitride sintered body, is placed in a cavity resonator, irradiated with microwaves (M), and subjected to a magnetic field (H) applied by electromagnets. An amount of microwaves absorbed by the object is measured by a microwave absorption measuring unit. This amount of microwave absorption is obtained from an electron spin resonance spectrum. The concentration of unpaired electrons in the object is obtained from the measured amount of microwave absorption on the basis of a known relation between an amount of microwave absorption and concentration of unpaired electrons.

Abstract: The invention provides method of electron spin resonance enhanced magnetic resonance imaging of a subject, for example a human, animal or inanimate body, in which said subject is exposed to radiation of a frequency selected to stimulate an esr transition in a paramagnetic species in said subject whereby to effect dynamic nuclear polarization, wherein said exposure to radiation is arranged such that within the region of said subject so exposed the capacity of said radiation to stimulate a said transition is relatively enhanced in at least one volume (a region of interest (ROI)), i.e. a method in which one or more regions-of-interest within the subject under study are selected by making it possible for an enhancement agent to act more effectively in that region than outside. The method for example also allows flow processes within a body to be monitored to provide the operator with images or data sets indicative of the spatial and/or temporal characteristics of flow from the ROI.

Abstract: Electron spin resonance spectrometers comprise a sample cavity located between the poles of a permanent magnet, means for applying microwave energy to the cavity, means for measuring the frequency of the microwave energy applied to the cavity, means for controlling the magnetic field strength in the cavity, means for detecting changes in cavity Q and accordingly changes in the level of microwave power reflected back from the cavity, and means for analyzing the changes in reflected power. In accordance with one aspect, a nuclear magnetic resonance probe including a standard sample is placed adjacent the sample cavity, means are provided for measuring the nuclear magnetic resonance frequency in the standard sample, calculating the magnetic field to which the sample and the adjacent cavity are subjected therefrom and applying the results of the calculation to control the magnetic field strength in the cavity.

Abstract: A resonator is provided for electron spin resonance spectroscopy. The resonator comprises a first wall element which delimits a cavity and which is in releasable contact with other wall element delimiting the cavity. The connection between the first wall element and at least one of the additional wall elements is effected only by spring force (single figure).