Mu-Metal Chamber Overview
In most applications, Mu-metal is not the first choice material for manufacturing a vacuum chamber. It is both more expensive as a material and more involved in manufacturing processes required.
Mu-metal chambers are required in applications such as electron microscopy where static and low frequency magnetic fields would be detrimental to the process or experiment.
What is Mu-metal?
Mu-metal is a nickel-iron alloy with very high magnetic permeability that has a low coercivity that saturates at low magnetic fields, resulting in excellent shielding properties.
Magnetic shielding works by redirecting the propagation of magnetic field lines so that magnetic flux flows through the walls of the shield itself, by-passing the inside of the vacuum chamber.
What can be made from Mu-Metal?
It can be used to manufacture vacuum chambers, and is also used to reduce the effects of magnetic fields by installing multiple liners or shields inside or outside the chamber. This can be particularly beneficial when retrofitting an existing vacuum chamber.
Design & Manufacturing Requirements:
- Increasing both the material thickness and length improve the performance of the shield.
- During fabrication, the grain structure of the material is weakened, compromising the performance of the shield. To combat this, the Kurt J Lesker Company performs a final full heat treatment in a controlled atmosphere that results in larger grain structure and ensures the best shielding performance.
- Chambers are manufactured with collars on the main body that will allow for welding of a stainless steel ConFlat® flange. It is common to manufacture these using 316LN ESR flanges due to their low magnetic permeability. All welds are vacuum brazed to ensure that the chamber is leak tight.
- Chambers usually require ports and the cutouts in the shield required to use these have a detrimental effect on the shielding properties. For ports that do not require full access, such as pumps and gauges, Kurt J Lesker can design these with multiple smaller cutouts, maintaining magnetic shielding whilst still allowing for conductance through the shield.
Chambers, shields and Liners can be made with:
- 5mm/ 0.197" Maximum Thickness
- Leak tight to 2 x 10-10 STD CC.S
- Manufactured using 316LN ESR flanges
- Annealed to Fully Restore Magnetic Shielding Properties
- Optional UHV Bakeout & RGA Scans Available.
Please contact firstname.lastname@example.org with your requirements for Mu-metal Vacuum Chambers, Shields and Liners.