Magnetically Shielded Chamber
The magnetically shielded chamber (MSC) is specifically designed for the precise measurement of extremely weak magnetic fields. It provides an environment in which external magnetic disturbances—most notably the Earth’s magnetic field—are significantly suppressed, enabling the reliable operation of highly sensitive magnetometers. Such conditions are essential for experiments in fundamental physics, biomagnetism, and metrology, where even the smallest magnetic fluctuations can distort results.
The chamber is constructed from three nested layers of high-permeability mu-metal, a nickel–iron alloy renowned for its excellent magnetic shielding properties. These layers work together to guide and absorb external magnetic field lines, thereby reducing their influence in the measurement volume. This shielding concept ensures that both static (DC) and dynamic (AC) magnetic disturbances are effectively minimized.
As a result of this sophisticated design, the magnetically shielded chamber achieves a frequency-dependent shielding factor of approximately 200 (46 dB) and more at 0.01 Hz and up to 10000 (80 dB) and more at 6 Hz. These values demonstrate the chamber’s ability to attenuate low-frequency magnetic noise, which is particularly challenging to suppress but crucial for high-precision measurements. The residual DC magnetic field inside the chamber is as low as about 20 nT in all spatial directions, creating an exceptionally quiet magnetic environment. This low residual field allows researchers to perform accurate measurements without the need for extensive additional compensation systems.
The high technical standard of the chamber supports the operation of state-of-the-art magnetometers, including optically pumped magnetometers (OPMs). These devices are among the most sensitive magnetic sensors available today and benefit greatly from the ultra-low-noise conditions provided by the chamber. Currently, several OPM systems are successfully operated within the chamber, demonstrating its reliability and suitability for advanced experimental setups.
Beyond its core shielding capabilities, the chamber is also designed with practical usability in mind. It typically includes a non-magnetic interior workspace, specialized feedthroughs for cables and optical fibers, and vibration-isolated mounting structures to prevent mechanical disturbances from influencing measurements. Careful attention is paid to the selection of all materials used inside the chamber to ensure that they do not introduce unwanted magnetic noise.
In summary, the magnetically shielded chamber represents a highly advanced facility for magnetic measurements, combining multiple layers of shielding, low residual fields, and compatibility with cutting-edge sensor technology. It provides CRC researchers with a controlled and stable environment that is indispensable for exploring weak magnetic phenomena and pushing the limits of measurement accuracy.
| Further details | |
|---|---|
| Place | Building E, room xxx |
| Internal phone number | xxxx |
| Responsible PIs | Dr. Dirk Meyners Prof. Dr.-Ing. Gerhard Schmidt |
