The magnetic fields generated by a variety of everyday sources – including power networks, electrical devices and even the earth’s core – do not usually interfere with day-to-day life. However, the performance of extremely high precision technologies – such as scanning electron microscopes (SEMs) – can be negatively impacted by even the most minute magnetic disturbances, preventing the equipment from being used to its full potential. Fortunately, magnetic field cancelling systems have been developed to attenuate such disturbances, and the University of Granada in Spain has recently installed anSC24 Magnetic Field Cancelling System to optimise the performance of its SEM set-up.
Electron microscopes are used in a variety of scientific disciplines, imaging everything from the inner workings of cells to the crystalline structures of engineering materials, making access to state-of-the-art microscopy equipment equally essential for both academic and private researchers. Rocío Márquez Crespo, a technician at the University of Granada’s Scientific Instrumentation Centre, explained: “I’m responsible for the Scanning Electron Microscopy Unit – located in the Faculty of Pharmacy – which provides services to research groups both here at the university and to other academic centres across Spain, as well as for many public institutions and private companies. As you can imagine, we support an incredibly wide range of applications, but the common thread running between them is the need for extremely high resolution images, and we facilitate this by providing access to both field emission and dual beam SEMs.”
SEMs are noted for their ability to measure features at the atomic level, but their accuracy and repeatability are heavily dependent on their environment, with factors such as vibration, temperature and humidity all affecting image quality. They are especially vulnerable to external magnetic fields, since the images are generated using a beam of charged particles, which can be easily deflected by magnetic field disturbances. Rocío continued: “During the installation of our dual beam microscope, we noticed that images at the highest magnification settings were becoming distorted, and we suspected that it was due to magnetic field interference. An environmental survey carried out by the microscope manufacturer confirmed this to be the case, and we were encouraged to purchase a magnetic field cancelling system to alleviate these effects. We’ve been recommended Spicer Consulting products many times in the past by colleagues and local researchers who’ve had positive experiences with them, so the SC24 Magnetic Field Cancelling System was the obvious choice.”
The SC24 system is made up of a magnetic field control unit, up to two magnetic field sensors, and three orthogonal axis multicore cables installed in the room where field cancellation is needed. The ambient field is stabilised by dynamically generatingalmost equal and opposite field changes, boosting microscope performance and allowing clear images to be generated. “Once the system was installed by EloïseSAS – a local supplier – the image distortion present at high magnification levels disappeared at the flick of a switch. It was as simple as that,” Rocío concluded.
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