RF-Coil for the OCRA Tabletop MRI system

Hello OCRA and Tabletop community,

In this short blog I will share my radiofrequency (RF) -coil design for our OCRA Tabletop MRI system. The coil is a simple solenoid design. To make it sensitive to the measurement (Larmor) frequency it is built as an electrical resonator with parallel capacitance. To match its impedance to a 50 Ohm low noise preamplifier a matching capacitance is used. The coil resonance frequency is adjustable as these capacitances a realised with trimmer capacitors. Trimmer capacitors alone have a very limited range. so parallel fix value capacitors can be added.

The RF-coil is shielded by a RF-shield. It’s basically a faraday cage and protects the surrounding electronics or the magnet from the RF radiation. To avoid unreliable wrapping of copper tape the RF shield is made of 4 printed circuit boards (PCBs). The boards are placed in a rectangle and soldered edge to edge.

The 3D printable coil rack offers a 15mm open bore. The bore is open to both sides to allow continuous tube applications. Via screwable 3D printable plugs the bore ends can be closed. These plugs can also be designed as reducing sleeve to allow the alignment of smaller chemical test tubes.

In the attached .zip file you will find the production files for the PCBs, the 3D printable coil rack, a 15mm plug and a 10mm reducing sleeve. Details for the PCB production you will find in the README.

https://data.stimulate.ovgu.de/f/89d4f1929fdd40c5be6d/

When downloading the files, you declare to cite us as creator of the OCRA Tabletop RF coil when using in your projects or publications (Marcus Prier, Forschungscampus STIMULATE, Otto-von-Guericke University Magdeburg). You are not allowed to remove logos or references.

In this link you will find a detailed building instruction.

https://data.stimulate.ovgu.de/f/79734b47608248369c18/

If you have questions about the OCRA Tabletop RF-coil or interest in a preassembled PCB, Tabletop and OCRA components or even a whole OCRA Tabletop MRI system contact me via marcus.prier@ovgu.de.

Best regards,

Marcus