Richard W. Bowtell1, Michael Packer 2, Peter Hobson 2, James Leggett1, Niall Holmes1, Paul Glover 1, Matthew Brookes1, and Mark Fromhold2
1Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, United Kingdom, 2School of Physics and Astronomy, University of Nottingham, Nottingham, United Kingdom
1Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, United Kingdom, 2School of Physics and Astronomy, University of Nottingham, Nottingham, United Kingdom
We show
how to analytically calculate the fields that are produced by simple coils inside
a finite-length, cylindrical mu-metal shield with end-caps.
Figure 1
(a) Schematic diagram cylindrical shield with end-caps of radius,
b, and length, 2Ls,
and coil of radius, a. Illustrative coil wirepath and direction of current flow indicated. (b) Multiple reflections
of the coil due to the end-caps (dotted lines indicate reflected versions of the wirepath).
Figure 2 (a) Experimental set-up: fields from loop and saddle coils measured using a fluxgate magnetometer inside a 30 cm diameter 1 m long cylinder formed from 1.5 mm thick mu-metal. (b) Helmholtz-type coil formed from two loops of radius a, separated by a distance 2d, carrying current in the same sense.
