Electrical circuit in the magnetic field of an MR apparatus

Patent metadata

Field	Value
Publication number	US-9606201-B2
Application number	US-201314072826-A
Country	US
Kind code	B2
Filing date	Nov 6, 2013
Priority date	Nov 16, 2012
Publication date	Mar 28, 2017
Grant date	Mar 28, 2017

Abstract

An electrical circuit with one or more semiconductor components ( 10 ) is characterized in that at least one semiconductor junction of at least one of the semiconductor components of the electrical circuit is disposed such that the average direction of motion of the charge carriers in the semiconductor junction is essentially parallel to the lines of force of the magnetic field B 0 , wherein the corresponding semiconductor component is disposed directly on a substrate ( 12 ), which is made of a material with good thermal conduction properties. In this way, undistorted characteristics of the semiconductor component used can be ensured despite the very strong magnetic field and the low operating temperatures.

First claim

We claim:

1. An electrical circuit adapted for use in an MR apparatus, the MR apparatus structured for MR (“magnetic resonance”) spectroscopy or tomography, the MR apparatus comprising:
a magnet or a superconducting magnet structured to produce a B 0 magnetic field of at least 1T in a direction of a z-axis in a working volume disposed on the z-axis about z=0;
a cryogenic MR receiver; and
an MR transmitter, wherein the electrical circuit is disposed in the MR apparatus as part of the cryogenic MR receiver and/or of the MR transmitter at an operating temperature below 100K and in the B 0 magnetic field,

the electrical circuit comprising:
one or more semiconductor components, wherein at least one semiconductor junction of at least one of said semiconductor components is disposed such that an average direction of motion of charge carriers in said semiconductor junction is substantially parallel to lines of force of the B 0 magnetic field; and
a substrate, said substrate being made of a material having thermal conduction properties better than 10 Wm −1 K −1 , wherein said semiconductor component having said semiconductor junction is directly disposed on said substrate.

2. The electrical circuit of claim 1 , wherein all said semiconductor junctions of all said semiconductor components of the electrical circuit are oriented such that said direction of motion of said charge carriers is substantially parallel to the B 0 magnetic field lines of force.

3. The electrical circuit of claim 1 , wherein said substrate is made of an electrically conductive substrate material and said semiconductor components of said electrical circuit are thermally conductively connected to said substrate.

4. The electrical circuit of claim 3 , wherein said substrate material comprises copper, silver and/or aluminum.

5. The electrical circuit of claim 1 , wherein said substrate is made of an electrically insulating material.

6. The electrical circuit of claim 5 , wherein said substrate material comprises ceramic aluminum oxide, aluminum nitride, sapphire, beryllium oxide and/or silicon oxide.

7. The electrical circuit of claim 1 , wherein the electrical circuit is disposed in a vacuum.

8. The electrical circuit of claim 1 , wherein said substrate is made of a material having thermal conduction properties better than 10 Wm −1 K −1 , which is connected to a heat sink.

9. The electrical circuit of claim 1 , wherein all materials used are non-magnetizable.

10. The electrical circuit of claim 1 , wherein RF (“radio frequency”) switching diodes, RF limiter diodes and/or varactor diodes are provided as said semiconductor components.

11. The electrical circuit of claim 1 , wherein active elements FET and/or bipolar transistors are provided as said semiconductor components.

12. The electrical circuit of claim 1 , wherein initial materials of said semiconductor components comprise GaAs, GaN, silicon, germanium and/or SiGe.

13. A method for operating the electrical circuit of claim 1 , the method comprising the step of amplifying an MR signal.

14. A method for operating the electrical circuit of claim 1 , the method comprising the step of tuning and/or matching an MR receiver coil.

15. A method for operating the electrical circuit of claim 1 , the method comprising the step of reducing a current induced by an MR transmitter coil in an MR receiver coil and/or switching over the MR receiver coil to transmit during transmission.

Assignees

• Bruker Biospin Ag

Inventors

• Schwilch Arthur
• Marek Daniel
• Luke Martin

Classifications

• G01R33/32 Primary

  Excitation or detection systems, e.g. using radio frequency signals · CPC title

• G01R33/34015 Primary

  Temperature-controlled RF coils · CPC title

• A61B5/055 Primary

  involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging · CPC title

• G01R33/3628 Primary

  Tuning/matching of the transmit/receive coil · CPC title

• G01R33/3657

  Decoupling of multiple RF coils wherein the multiple RF coils do not have the same function in MR, e.g. decoupling of a transmission coil from a receive coil · CPC title