Claims
- 1. A magnetic system comprising a superconducting magnet coil system for generating a magnetic field in a direction of a z axis in a working volume disposed about z=0, the system comprising:
a radially inner partial coil means, said inner coil means generating a first homogeneous field in the working volume; a radially outer coil means coaxial to said inner coil means, said outer coil means generating, per se, an inhomogeneous field in the working volume; and a field forming device of magnetic material disposed radially between said inner and said outer coil means and coaxial with respect to said inner coil means and said outer coil means, wherein said field forming device produces, together with said outer coil means, a second homogeneous field in the working volume, with said magnetic material of said field forming device being substantially magnetically saturated, and a magnetization of said field forming device points substantially parallel or anti-parallel to the z axis.
- 2. The magnetic system of claim 1, wherein said field forming device is disposed cylindrically symmetrically about the z axis.
- 3. The magnetic system of claim 1, wherein said inner coil means and said outer coil means are electrically connected in series to form one single current path, and further comprising a superconducting switch bridging said one single current path.
- 4. The magnetic system of claim 1, wherein said inner coil means and said outer coil means are electrically separated to form a first and a second separate current path, and further comprising a first superconducting switch bridging said first separate current path and a second superconducting switch bridging said second separate current path.
- 5. The magnetic system of claim 4, wherein, during operation, said outer coil means is inductively charged by said inner coil means.
- 6. The magnetic system of claim 4, wherein said inner partial coil means and said outer coil means can be charged with currents having one of equal and opposite polarity.
- 7. The magnetic system of claim 1, wherein each of said inner partial coil means and said outer coil means produces a magnetic field in the working volume of opposite direction along the z axis.
- 8. The magnetic system of claim 7, wherein said inner coil means has a magnetic dipole moment which is approximately equal in value and opposite in sign to that of said outer coil means together with said field forming device.
- 9. The magnetic system of claim 1, wherein said field forming device consists essentially of a ring of axial length LP having an inner radius RiP, wherein LP is approximately equal to RiP.
- 10. The magnetic system of claim 1, wherein said field forming device consists essentially of two rings of axial length LQ having an inner radius RiP, which are disposed symmetrically about z=0 at a separation DQ, wherein DQ<0.5·RiP and (DQ+2 LQ) is approximately equal to RiP.
- 11. The magnetic system of claim 9, wherein said outer coil means consists essentially of a solenoid coil of axial length LC2 having an inner radius of RiC2, wherein LC2 is approximately equal to twice the inner radius RiC2 or greater.
- 12. The magnetic system of claim 10, wherein said outer coil means consists essentially of a solenoid coil of axial length LC2 having an inner radius of RiC2, wherein LC2 is approximately equal to twice the inner radius RiC2 or greater.
- 13. The magnet system of claim 1, further comprising means for high-resolution magnetic resonance spectroscopy.
- 14. A method for homogenizing said outer coil means using said magnetically saturated magnetic field forming device magnetized parallel or anti-parallel to the z axis and which is cylindrically symmetrical with respect to the z axis of claim 2, wherein field inhomogeneities Hn(C2) of said outer coil means which vary along the z axis with the nth power of z, are compensated for n=1, 2, 3 and 4 through corresponding field inhomogeneities Hn(P)=−Hn(C2) of said magnetic field forming device (P), wherein said field inhomogeneities Hn(P) are calculated by assuming a cylindrical surface current JS on each radially inner and each radially outer surface S=SIk and S=SAm of said magnetic field forming device (P) with a contribution Hn(S) to the field inhomogeneity Hn(P) of
- 15. A method for compensating residual inhomogeneities in the field of the magnetic system of claim 1, said field inhomogeneities having a quadratic z dependence along the z axis, the method comprising the step of varying a current in said inner coil means and a current in said outer coil means in a same suitable fashion.
- 16. A method for compensating residual inhomogeneities in the field of the magnetic system of claim 4, said field inhomogeneities having a quadratic z dependence along the z axis, the method comprising the step of suitably varying a current in said outer coil means and of varying a current in said inner coil means in a different manner to keep the field constant in the working volume at z=0.
- 17. A method for calculating a field contribution H0(P), in the working volume at z=0, of said magnetically saturated magnetic field forming device, magnetized parallel or anti-parallel to the z axis and being cylindrically symmetrical with respect to the z axis of claim 2, wherein a cylindrical surface current JS is assumed on each radially inner and each radially outer surface S=SIk and S=SAm of said magnetic field forming device (P) whose contribution H0(S) to H0(P) is
- 18. A method for calculating a magnetic dipole moment of said magnetically saturated magnetic field forming device (P) magnetized parallel or anti-parallel to the z axis and being cylindrically symmetrical with respect to the z axis of claim 2, wherein a variable
Priority Claims (1)
Number |
Date |
Country |
Kind |
100 46 182.4 |
Sep 2000 |
DE |
|
Parent Case Info
[0001] This application claims Paris Convention priority of DE 100 46 182.4 filed on Sep. 19th, 2000 the entire disclosure of which is hereby incorporated by reference.