University of Massachusetts Medical School

University of Massachusetts Medical School

Cryo EM Magnetic Shielding

New England’s First-of-its-Kind Cryo-Electron Microscopy Facility
Cutting-edge microscope facility opens on UMass Medical’s campus

 

Cryo EM Magnetic shielding was installed in two imaging suites (Titan Krios and Talos Artica ) at UMASS Medical to attenuate AC ELF magnetic field levels. Summary evaluation follows:

At tool column, AC ELF field levels are well within tolerance, indicating the Titan Krios and Talos Artica Imaging suite AC ELF and DC Magnetic field mitigation with magnetic shielding is performing successfully. Along perimeter of the shielded area, magnetic field levels were lower than the resolution of the probe being used to obtain data (0.04 mG) in that area.  As such, the shield is considered to successfully conform to the AC ELF performance specifications.

At each tool column, DC quasi-static levels are consistently greater than specified tool tolerance. DC quasi-static field levels are generated by moving ferromagnetic masses moving through the Earth’s geomagnetic field. Specifically, on this site, levels are generated by workers moving through the hallways outside of the microscopy suites. Analogous field levels will be generated by pedestrians and moving carts through the hallway during the normal course of operation of the TEM instruments.  As such, further mitigation for DC-quasi static fields with an Active Compensation System (ACS) was highly recommended by Vitatech for both electron microscopes.   A combined active vibration isolation platform was integrated into the AC ELF floor shield for each EM tool with a dedicated Active Compensation System.

AC ELF and DC quasi-static data was collected at the position of the tool column at elevations of 0.5, 1.0, and 2.0 meters above the floor.  Additional AC ELF data was collected at 1 foot intervals along the perimeter of the entire shielded area.  The greatest peak values along each respective axis are displayed in the below table.  NOTE: The AC ELF and quasi-static DC after shield data shown is before installation of the ACS around the tool columns.   Full tool EMI compliance was achieved after the ACS was installed and operational.

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