ERDFIII_Magnetically shielded cage

A magnetically shielded cage (or room) is a specially designed space that minimizes external magnetic fields, such as the Earth's magnetic field and electromagnetic interference. It is essential in paleomagnetic research for accurately measuring weak magnetic signals in rock samples. Small enclosures, such as sample storage spaces, are typically constructed using multiple layers of mu-metal or other high-permeability materials that absorb and redirect magnetic fields. Larger cages, designed to accommodate full-scale paleomagnetic instruments, often incorporate active compensation coils to further reduce residual magnetic fields. These shielded environments enable precise paleomagnetic measurements by ensuring that natural remanent magnetization (NRM) can be analyzed without external disturbances. Additionally, they help maintain the magnetic cleanliness of samples, preventing unwanted contamination, and provide a stable, interference-free environment for calibrating sensitive instruments such as magnetometers.