Patent ID: 8884621

Claim:
A system, designed to generate magnetic fields of high uniformity within an examined object, wherein the system is composed of two pairs of coils, which have the same radiuses, are situated coaxially, are attached to the housing of the tomograph in a permanent, detachable manner, and in which the current flows in the same direction and sense, and wherein the distances d 1 and d 2 from the plane of symmetry for the pairs of coils and the numbers of the ampere-turns for the pairs of coils are found from the equations: d 1 R = 0.25153 + 0.06065 ⁢ ⅇ - t - 0.00173 ⁢ t - 0.00001 ⁢ t 2 ⁢ ⁢ d 2 R = 0.96173 - 0.06781 ⁢ ⅇ - t - 0.00466 ⁢ t + 0.22810 ⁢ t ⁢ ⁢ ⅇ - t + 0.00003 ⁢ t 2 ⁢ ( NI ) 2 / ( NI ) 1 = 2.12 + 0.02 ⁢ t ( a ) or d 1 R = 0.28115 - 0.00004 ⁢ t + 0.0092 ⁢ ln ⁢ ⁢ t ⁢ ⁢ d 2 R = 1.11207 + 0.01702 ⁢ t + 3.4 · 10 - 6 ⁢ t 2 - 0.00263 ⁢ t ⁢ ⁢ ln ⁢ ⁢ t ⁢ ( NI ) 2 / ( NI ) 1 = 2.12 + 0.02 ⁢ t ( b ) where d 1 is the distance between a first pair of the coils and the plane of symmetry, d 2 is the distance between a second pair of the coils and the plane of symmetry, R is a coil radius, (NI) 1 is an ampere-turn size for the first coil, (NI) 2 is an ampere-turn size for the second coil, and 1≦t≦82 for the equation (a) or 1≦t≦394 for the equation (b), where t is a parameter, linearly related to the ratio of the ampere-turns of the second coil and the ampere-turns of the first coil.