842-043 is a high-precision replacement assembly equipped with thoria-coated iridium filaments, designed for MKS Microvision 2 and/or e-Vision Residual Gas Analyzers (RGA). This assembly is the central component where gas molecules are ionized by electron impact before being directed into the mass filter.

MKS ion sources are engineered for rapid field serviceability. The modular design allows the entire 842-043 source to be removed and replaced in minutes, or for the filaments to be swapped out without the need for specialized alignment tools or jigs. The user serviceable analyzer design allows the ion source to be easily removed and dismantled for cleaning. The dual independent filaments on the MKS analyzers can be easily changed by removing the two barrel connectors and loosening the two holding screws.

The thoria-coated filaments in the 842-043 are ideal for semiconductor and high-purity research applications. In environments with high hydrocarbon concentrations, the tungsten version (842-042) is typically recommended instead.

To verify compatibility with specific RGA models, consult the “specifications” section below.