842-071 is a high-pressure replacement filament assembly specifically designed for the HPQ (High Pressure Quadrupole) series of mass spectrometry analyzers. Featuring a thoria-coated iridium construction, this assembly is engineered to provide reliable electron emission for gas ionization in processes that operate at significantly higher pressures than standard residual gas analyzers (RGAs).

842-071 is a standard replacement part for the HPQ2 and HPQ2S high-pressure analyzers.

The maintenance-conscious design of the HPQ2 and HPQ2S incorporates twin filaments, where the second "back-up" filament enables continued operation in the event of a filament failure.

842-071 thoria filament is particularly well-suited for semiconductor processing and other "clean" environments where oxygen may be present. While resistant to oxidation, users should avoid using these filaments in environments with heavy metallic or organic contaminants, such as oil back-streaming, which can "poison" the thoria coating and degrade accuracy.

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