The definition zero gauss chamber normally applies to a magnetic shield made from µMetal that is designed to provide a calibration zone free from the earth’s natural magnetic field. These chambers are normally rather small and are commonly used for the calibration of measurement devices such as Hall probes.
Zero gauss chambers can vary from a single layer of RNi5 to five or more layers of RNi5 and/or other soft magnetic material layers. The decission which material and how many layers have to be used depend on your specific requirements.
Multiple layer shields are usually larger and are used frequently in a research environment where it is not only necessary to shield out the earth’s magnetic field, but in some cases, to create a new magnetic field inside the shield which has known characteristics regarding stability and field strength over given moments in time.
In the cases of multiple layer zero gauss chambers it is very important that each layer of the shield is magnetically isolated from the next. Magnetic Shields Limited has conducted extensive investigation and testing to identify the best materials for isolation which depending on the customer’s criteria can vary significantly depending on environmental conditions.
The typical shape for a zero gauss chamber is cylindrical and this offers the most effective levels of shielding. The chamber will normally have a removable lid to prevent magnetic field leakage and allow easy access to the chamber. It is common for the lid to have holes or cut-outs for cable feed-through, and these should be kept to a minimum wherever possible. If there is a requirement to position holes or cut-outs in the main cylinder, it is recommended that a shield extension perpendicular to the main tube is placed around the hole.
Additional framework to aid positioning/structural integrity can be designed to suit your individual requirement and any finishing specifications such as painting can be made, too. All of the operations required to manufacture your shield are carried out in MSL's manufacturing facility, allowing complete control, from the choice of raw materials to the final heat treatment to achieve optimum magnetic properties in the finished product.
Small zero gauss chambers are usually available from stock and larger/bespoken shields are typically manufactured on a 5-6 week lead-time.