Herzan Helps Remove Magnetic Fields
Magnetic fields can be the most noticeable and limiting form of environmental noise affecting scanning electron microscopes (SEMs) and transmission electron microscopes (TEMs). AC Fields often present themselves as producing sharp jagged edges (as depicted above), while DC fields often present themselves as wavy lines in the image. This level of disturbance can either limit the ability of the SEM and TEM to retain clarity from the sample being measured or require a mitigation solution.
Fortunately, multiple mitigation solutions are available based on what best suits the lab or researcher.
Removing Magnetic Fields At the Source
Addressing magnetic fields at the source can be the most cost effective and immediate solution (if available). AC Field issues can often be the result of current-carrying power lines, unintentional currents in loops (i.e. ground conductors), or lighting and air conditioning systems; while DC Field issues are more related to large metal objects moving within the earth’s magnetic field. Removing or re-conditioning these sources from the room can have a significant impact on the imaging effects of a SEM/TEM, enabling the lab to meet environmental specification and researcher to focus on what matters most: their research.
Moving Rooms for SEMs/TEMs
Moving the lab location for a SEM/TEM to a lab with lower magnetic fields can be a simple and free solution. Site surveys are helpful in determining the ambient AC/DC Field levels of various rooms, where researchers can compare the specification set by the manufacturer for their SEM/TEM with the measured AC/DC Fields.
SEM/TEM manufacturers almost universally require a site survey be performed at the customer site prior to installation. Their team of field service engineers often capture this data, or partners like Herzan are called upon to perform local site surveys for their customers. Choosing the right lab room is key and can save significant time and money not having to mitigate magnetic fields from the lab.
When researchers are unable to improve the local AC/DC fields in their lab and are set on a specific lab room to operate their SEM/TEM, magnetic field cancellation systems are recommended. Magnetic field cancellation systems offer dynamic cancellation to AC and/or DC fields for nearly every SEM/TEM. Magnetic field cancellation systems are substantially less expensive than passive shielding solutions like placing mu metal throughout the lab.
The SC 22 System provides a cost-effective solution for addressing AC fields, while the SC24 System provides high-performance AC/DC field cancellation. Both solutions are offered by Herzan to customers in North America and are manufactured by Spicer Consulting: the world’s leader in magnetic field cancellation.