*6.2.2. 1.0 T open biplanar MRI*

100 Superconductors – Materials, Properties and Applications

**Figure 13.** The current map and coils distribution of half model

**Figure 14.** The homogeneity over 500 mm DSV and stray field distribution

Stray field distribution(Gauss)

producing the required magnetic strength and the homogeneity. The outer layer with a pair of negative current direction coils for reduces the stray field strength. The homogeneities and stray field distributions are shown in Fig. 14. The coils parameters are shown in Table I. The operating current density and actual current margin are 148 MA/m2 and 0.7546, the

0.8

0.4


<sup>0</sup> 0.1 0.2 0.3 0.4 0.5 0.4

z(m)

0 0.5 1 1.5 2 2.5 3

<sup>0</sup> 0.5 <sup>1</sup> 1.5 <sup>2</sup> 2.5 <sup>3</sup> <sup>0</sup>

θ(rad)

θ(rad)

r(m) z(m)

0.6

maximum magnetic field and hoop stress are 5.43 T and 145.16 MPa, respectively.

0

0.5 -4 -2 0 2 4 x 104

0.5


Homogeneity on DSV(ppm)

0.6

r(m)

0.7

0.8

I(A)

The unshielded open biplanar MRI system has a central field strength of 1.0 T, inner and outer radius of 0.0 and 0.90m, lower and upper z positions for two ends of 0.40m and 0.45 m, and field quality of 15ppm over 450 mm DSV.

**Figure 15.** A quarter model current map and coils distribution

The *Nr*, *Nz*, *Nd*, and *Ns* were set as the same as the design of 1.5 T actively shielded MRI system. A quarter model current map for the LP stage and the coils distribution are shown in Fig. 15. The coils distributions with single layer have six coils, the largest coils with maximum field of 5.26 T are the outermost coils with positive current direction. The coils parameters are shown in Table II. The operating current density and actual current margin are 150 MA/m2 and 0.74, the hoop stress is 128.2 MPa, respectively.
