392017401, Internal filaments (2 filaments on one disk, Agilent 240-MS Ion Trap

The Agilent 240-MS ion trap filament disk is an internal ionization source service assembly containing two filaments mounted on one disk. Each electrically heated rhenium ribbon produces electrons by thermionic emission for electron ionization and related internal-source operation. The instrument uses one filament at a time, with the second available when the first reaches end of life. Filament condition can affect ionization stability, sensitivity and source performance, but a loss of signal should also prompt checks of source cleanliness, electronics and operating settings. Replacement requires shutdown, safe cooling, appropriate vacuum venting and the instrument-specific ion-source maintenance procedure. Handle the assembly without touching the fragile filament ribbons or contaminating source surfaces. After servicing, restore operating vacuum and complete tune, source and mass-spectrometer performance checks. The dual-filament disk is designed for the 240-MS internal ionization assembly; it is not a general GC inlet consumable.