At the Technical University Dresden, two electron microscopy rooms have been magnetically shielded with the Systron LabShield® shielding system. The magnetic shielding was necessary, since the nearby tramway created massive DC shifts. In addition, locally generated AC fields from the in house electrical system and surrounding electrical equipment had to be shielded, too.
For best attenuation, mu-metal, also called permalloy, was applied in it's highest quality to the floor, the walls and the ceiling, leaving only a few openings for media feed troughs and foundation. Since maximum performance was required, the door was fully shielded, too and unused feed through openings were covered with mu-metal plates.
The big challenge with the use of mu-metal lies therein, that the mu-metal is not stressed, neither during transport, nor during installation. If mu-metal is stressed in any way, it permanently looses it's magnetic properties and consequently the shielding properties. With the expertise gained over the years, Systron is able to plan, design and install room shielding without altering the properties, however, many developments were necessary to ensure no stress is induced to material.
Today, the final performance of a LabShield® shielded room can be well predicted with software modeling and thus, performance can be guarantied, too. However, to proof functionality, measurements are taken after completion of the shielding work.