Bucking Coils and Gradient Coils

Bucking Coils

Mössbauer effect measurements can be made without the application of a magnetic field. Additional information can be gained, however, with magnetic hyperfine splitting by placing the absorber in a magnetic field. Applied fields are also useful in Mössbauer effect studies of magnetic materials. In addition, low temperatures are frequently used in experiments involving samples having short spin relaxation times. Where both low temperatures and magnetic fields are planned, it is natural to consider the use of a superconducting magnet.

Many experiments of this type are performed using proportional counters that are relatively insensitive to magnetic fields and can be used in conjunction with standard solenoids. Scintillation counters are frequently used for higher energy gamma rays, however, and the photomultiplier tube used with the scintillation counter is susceptible to magnetic fields. A bucking coil can be placed on either end of the magnet to reduce the field at the source and/or the detector.

Gradient Coils

Magnetic susceptibility measurements can be made with great precision by measuring the force exerted on a sample placed in a magnetic field that is shaped to maximize BdB/dx. Magnets of this type are comprised of two parts: a main coil that is relatively homogeneous and a second coil section that generates a linear field gradient over a specified volume.

Bucking Coils and Gradient Coils