Applications requiring magnetic shielding are becoming more diverse all the time due mainly to the increasing use of sophisticated sensors and transducers in all types of electronic control systems. In this article I will concentrate on five of the more common applications.
Traditionally magnetic shields have always been used to shield cathode ray tubes and indeed there are still many applications for this type of shielding; for example in thermal imaging cameras, scintillation tubes and “head up” displays. In these applications the shield protects the sensitive area of the tube from extraneous external magnetic fields ensuring that the accuracy of the particular tube meets the design criteria even when operating in “hostile” magnetic environments.
A much newer and growing application for shielding is for sensitive transducers; such as Hall Effect devices, fibre optic gyroscopes, and other linear and rotational transducers including accelerometers.
These types of shields can vary considerably in size but the main common design point is to enclose almost totally the device acting as the transducer to provide the best possible environment for ensuring that the device is recording a magnetically “clean” signal this is especially important in safety critical applications in aerospace and fast moving CNC machinery.
Mumetal® shielding is also widely used for screening sensitive electron microscopes and analysis equipment; in microscopes it shields the magnetic lenses and in analysis equipment it provides the necessary “magnetically clean” environment for accurate results to be collected by the various types of sensor used. These types of shields tend to be large and in relatively thick material, sometimes even with multiple layers to achieve the very high levels of shielding required.
Mu-metal® shielding is also widely used for screening sensitive transformers; applications for this type of device include high performance audio amplifiers, theatre lighting systems and very sensitive current transformers for human protection, this type of shield is usually fabricated as a can form and again the main aim is to provide the best attempt at totally enclosing the transformer that is possible to achieve, whist allowing for wiring access.
Another application for Mu metal® shielding is fundamental research. This type of shield can be very large in size sometimes up to 6 metres long and 3 or 4 metres wide. They are frequently multilayer shields as there is usually the necessity to shield down to very low levels of field frequently in the Nano Tesla range or even less.
These shields have to be very carefully designed to avoid “leakage” on the joins, and for very low fields the selection of all materials involved in the construction can be critical to the shield performance.
Applications include linear accelerators, Neutron beam research as well as the study of sub atomic particles.
sir
a perpendicular magnet
with holo shielding tube
how can calculating flux/field distribution inside the tube
thanks
Dear Sir,
In order to assist you we would need some further information;
1. Is the magnet inside or outside of the tube?
2. Is it central or offset from the tube?
3. What is the proximity of the magnet to the tube?
4. What is the strength of the magnet?
5. What is the intended size, thickness and material of the tube?
With Kind Regards,
Hi
I´m part of a research group in History in Sao Paulo, Brazil. We are trying to build a vessel to protect magnetic memories (like those used in pen drives) from external magnetic fields so that sensitive data can be stored for long periods (we mean historical periods).
Could yo please explain for us the differences between Mu-metal or Giron Magnetic shielding film?
Anyway, do you think this method (involving memory chips in mu-metal or anything alike) will really protect the data?
Thank you