Screened electromagnetic coil of restricted length having optimized field and method
US5266913A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 27, 1991 |
| Grant date | Nov 30, 1993 |
| Priority date | — |
| Expiry date | Aug 27, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R33/4215
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A primary gradient coil and a screen coil for use with the primary coil are constructed to create a substantially null field adjacent to the screen coil and a substantially distortion free linear gradient field adjacent to the gradient coil. A method is disclosed for generating the coils by considering the screen coil to be of infinite length, deriving a Fourier transform of the axial and other components of the field in which the transform is the sum of the permissible harmonic modes on the coil surface in which a coefficient C.sub.n is derived representing the nth harmonic. A perfect screen coil is created and the number of terms C.sub.n selected using least squares optimization until there is no longer a significant change in the resulting field. Examples are given for creating unscreened, screened, linear, axial and transverse gradient field coils.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.