Magnetic Active Compensation System
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An ESCO Technologies Company Features: • Uniform protection from environmental AC/DC magnetic interference (1mHz to 1kHz) • Patented wideband negative-feedback design provides electronic magnetic compensation without the need for continuous re-calibration • Offers protection against fluctuations in magnetic fields caused by subways, electrical distribution equipment, elevators and moving vehicles • Can be applied to new or existing installations The ETS-Lindgren™ Magnetic Active Compensation System (MACS™) provides cost-effective, maintenance-free environmental magnetic field shielding solutions for high-precision Electron Beam instrumentation. The MACS is the highest-performance commercial active magnetic field compensation equipment available for protecting sensitive EM instruments from AC/ DC environmental magnetic fields. These reliable systems provide real time compensation of environmental magnetic field fluctuations caused by moving vehicles, trains, elevators, electrical distribution equipment, and other sources. ETS-Lindgren’s MAC systems provide a uniform solution, at DC and through low frequency, using a highly sophisticated electronic magnetic compensation technology. Utilizing a patented wideband negative-feedback electronic design, the equipment deeply attenuates interfering magnetic fields at a fraction of the cost of alternative methods, such as passive shielding or equipment relocation. Field attenuation at the protected E-Beam exceeds a factor of 30. This permits the successful operation of E-Beams- especially units with highly susceptible FEG emitters- at virtually any site. Applications MAC systems broaden siting possibilities by allowing E-Beams to be placed in locations where varying high magnetic field are present. As a result, they can be installed at sites that have been previously rejected due to magnetic field interference. In addition, if post installation site conditions change, the MACS can provide continuous protection. Performance ETS-Lindgren’s unique MACS-series active-feedback magnetic shielding technology provides instantaneous, high-level protection at any frequency or combination of frequencies within a wide passband. No other commercially available compensation system attains this high level of magnetic field cancellation at all frequencies that can interfere with EM operation. High level signals from the magnetic field sensor preamplifiers are conditioned and amplified by a phase-correcting signal processor and power driver in the controller chassis. Signal levels throughout the processing chain are supervised by an internal controller with front-panel programmable set-points for axial trip off. The controller also implements a setup algorithm for easy initial adjustment and provides continuous fail-safe fault monitoring for the internal power supplies and power amplifiers. Typically, the distortion known as astigmatism can be corrected by using variable electromagnetic compensation coils. To reduce interfering magnetic fields throughout the room, compensation

Magnetic Active Compensation System for Electron Beam Applications flux is generated by driven coils that are mounted along or near the room vertices. Coil sets for each axis are placed on opposing walls and consist of single 0.5” (1.3cm) o.d. cables installed in the plastic raceway. Cable installation is fast and unobtrusive. Maintenance-Free Operation MAC systems are designed to require no maintenance or adjustments following initial The image at left shows the silicon (110) lattice with resolution near the 1.4 Å requirement for observing “dumbells” while the image at right shows...