Proceedings Article | 29 August 2005
KEYWORDS: Electromagnetic coupling, Magnetism, Magnesium, Nanotechnology, Transformers, Research facilities, Transmission electron microscopy, Electromagnetism, Manufacturing, Standards development
High resolution imaging systems (i.e., SEM, TEM, FIB, etc.), diagnostic medical equipment (i.e., EEG, EKG, EMG, MRI, etc.), scientific instruments and computer equipment are all susceptible to various sources of electromagnetic and radiofrequency interference (EMI & RFI). Simply stated, optimal tool performance is the requisite practice in nanotechnology, medical and research environments. Compromised and degraded performance due to elevated ambient EMI/RFI environments that exceed the instrument's susceptibility thresholds is clearly not acceptable. In the United States uniform EMI/RFI susceptibility testing methods and procedures are not mandated by law. Although the FCC, Part 15, regulates RF interference with radio services and electric equipment from intentional and unintentional sources, it does not address susceptibility issues directly. Therefore, confusion abounds as each manufacturer presents their unique method to measure and document the ambient EMI/RFI environment to ensure optimal performance. VitaTech will examine the various frequency bands and waveforms of non-ionizing electromagnetic (EM) spectrum, review basic near and far-field EM theory, identify problematic EMI and RFI sources, and address the units of measurement and susceptibility. Examples of EMI/RFI instrument susceptibility will be presented for analysis with actual EMI/RFI site surveys and power frequency simulations. The paper examines several EMI/RFI industry standards including SEMI E33-94 and European Union EN 61000-6-1 and EN 61000-6-2. Finally, corrective strategies and costs to attenuate and control elevated EMI/RFI environments will be presented such as magnetic and RF shielding systems, active cancellation systems, RGS/EMT conduits for electrical power distribution, self-canceling MI cable systems and other mitigation techniques.
