Instrumentation Monthly Test | Measurement | Control
Superconducting magnets supplier, Cryogenic, has developed a new range of products that, it states, will eliminate the need for costly liquid-helium in a number of imaging and spectroscopic techniques.
Laboratory imaging systems and high resolution spectrometers based on Magnetic Resonance rely on strong magnetic fields. These are used to magnetise the atomic nuclei in the tissue or sample and the magnetisation generates signals that are manipulated to form images or yield information on chemical structure.
Generating such strong magnetic fields requires superconducting magnets, which must be cooled to close to absolute zero to function. Liquid helium is used for this, but is in increasingly short supply and becoming expensive.
Cryogenic have developed methods for cooling magnets without liquid helium and are now offering magnets for Magnetic Resonance Imaging (MRI), Nuclear Magnetic Resonance (NMR) spectroscopy, and Electron Spin Resonance (ESR) spectroscopy.
This will bring numerous benefits to the many laboratories and research institutes employing these techniques. As well as saving money, in some places where liquid helium is very hard to obtain it could make such techniques viable to use for the first time. It will also save time and effort.
Superconducting magnets can also quench occasionally – when the special wire stops being superconducting and suddenly starts generating lots of heat – and then any liquid helium surrounding the magnet rapidly boils off and must escape from the vessel housing the magnet.
Systems using liquid helium therefore require large areas with suitable ventilation facilities. Cryogenic’s magnets can quench safely in a confined space making them more versatile.
Unlike existing systems, Cryogenic’s cryogen free magnets are cooled to low temperature by mechanical refrigerators which require only electrical power and cooling water. The coolers rely on the compression and expansion of a fixed volume of helium gas supplied under pressure in a closed and self-contained circuit. The helium gas remains contained in the circuit and never condenses into liquid.
