Abstract: A radio frequency (RF) probe (10) for a nuclear magnetic resonance check weighing system produces a uniform magnetic field at the center of RF probe (10), has minimal sensitivity to electrical interference from external sources, shapes the magnetic field to minimize cross coupling from packages such as drug vials (22) not under test, and presents minimal airflow obstruction. RF probe (10) includes a coil (100) with a plurality of conductive loops (102, 104) having a rectangular cross section carried inside two opposing, rectangular cross section housings (106, 108), respectively. Housings (106, 108) are spaced apart and in parallel, creating an “open probe” configuration permitting a conveyor belt (28) carrying vials (22) whose contents are to be checked to pass between housings (106, 108), and allows airflow surrounding the vials (22) and conveyor belt (28) to pass substantially without obstruction.

Abstract: A method (10) permits determining the temperature in a magnetic resonance check weighing system (24) of a sample in a container (22) on a production line at the time of magnetic resonance testing. Method (10) includes the steps of determining a time-temperature correction factor for the sample in the container (50), measuring the temperature of the composite sample and the container at a time other than the time of magnetic resonance testing (70), and applying the correction factor to the temperature of the composite sample and container at a time other than the time of magnetic resonance testing (80).

Abstract: Magnetic resonance methods are provided for determining the mass of samples in vials (1) in a production line, each sample having a net magnetisation capability, including the steps of applying a first magnetic field in a first direction in an interrogation zone (25) for creating a net magnetisation within a sample located within the interrogation zone (25), applying an alternating magnetic field in a second direction in the interrogation zone (25) for temporarily changing the net magnetisation of the sample located within the interrogation zone (25), monitoring energy emitted by the sample as the net magnetisation of the sample returns to its original state and generating an output signal whose current amplitude is proportional to the energy emitted, comparing the current amplitude with like data obtained from at least one similar sample of known mass, and determining the mass of the sample.

Abstract: Magnetic resonance measurement methods for determining the mass of samples are provided in which magnetic field homogeneity is determined, compensation is provided for potential drifts in the measuring system, and the presence of metal in samples is determined. The methods include applying a magnetic field in a first direction in an interrogation zone for creating a net magnetisation within a sample located within the interrogation zone; applying an alternating magnetic field in a second direction in the interrogation zone for temporarily changing the net magnetisation of the sample located within the interrogation zone; monitoring energy emitted by the sample as the net magnetisation of the sample returns to its original state and generating an output signal having a characteristic which is proportional to the energy emitted; and comparing the output signal of the monitoring with other data.