Abstract: An NMR magnet system uses a Stirling cooler having a cold head that extends into a housing of the system to cool a cold shield surrounding a cryogen vessel. The system may have a damper located between the cooler and the cold shield to reduce a transmission of vibration from the cooler to a magnet coil immersed in the cryogen. The damper may be passive, or may be part of an active damping system that uses an acceleration sensor to drive an active damper that compensates for cooler vibration. A compensation apparatus may use a stored characteristic of a signal distortion caused by the vibration and, in response to a trigger signal from the cooler, apply compensation to an excitation signal provided to a sample by an NMR probe in a bore of the magnet coil, or to an FID signal from the sample that is detected by the probe.

Abstract: An NMR magnet system uses a Stirling cooler having a cold head that extends into a housing of the system to cool a cold shield surrounding a cryogen vessel. The system may have a damper located between the cooler and the cold shield to reduce a transmission of vibration from the cooler to a magnet coil immersed in the cryogen. The damper may be passive, or may be part of an active damping system that uses an acceleration sensor to drive an active damper that compensates for cooler vibration. A compensation apparatus may use a stored characteristic of a signal distortion caused by the vibration and, in response to a trigger signal from the cooler, apply compensation to an excitation signal provided to a sample by an NMR probe in a bore of the magnet coil, or to an FID signal from the sample that is detected by the probe.

Abstract: A hermetic module for containing at least one electronic component is integrated into a coaxial cable having a center conductor and an outer conductor. A housing defines an opening and an interior space therein. A body member is disposed within the interior space of the housing and defines a recess and a cavity adapted to contain the electronic component. The recess is in registration with the opening in the housing and is adapted to form an electrical contact with the outer conductor of the coaxial cable. A conductor member is disposed between the recess and the cavity, and includes a first end adapted to mate with the center conductor of the coaxial cable when the coaxial cable is inserted into the recess of the body member, and a second end disposed within the cavity. A sealing member disposed around the conductor member forms a seal between the recess and the cavity.

Abstract: A band-reject filter comprises a resonator with an adjustable resonator rod which is mounted in proximity to a co-axial assembly. The coupling rod passes thru the inner conductor of the co-axial assembly and extends into the resonator. At the end of the rod inside the resonator there is a coupling disc. Means are provided to adjust the distance between the resonator rod and the disc. The frequency rejected by the filter can be adjusted by either adjusting the length of the resonator rod or by adjusting the distance between the disc and the resonator rod.