16504 Ion Source Filament Inficon UL100 UL5000, LDS3000/800, Leybold

Description

16504 Ion Source Filament — INFICON UL100–UL5000, LDS3000/LDS800, Leybold Phoenix L200i/L300i The ion source filament is the electron emitter of the mass-spectrometer cell. It is heated until it emits, the electrons it releases ionise the gas drawn in from the test port, and only the helium ions that result reach the collector and become the leak signal. When it fails the detector still pumps down and still passes its vacuum self-test — but the helium signal is gone or will not calibrate. One filament covers an unusually wide range of machines. INFICON's UL series (UL100 through UL5000), the LDS3000 and LDS800 modules, Leybold's Phoenix L200i and L300i, and the LINXON LX218 all take the part INFICON lists as 16504 — also written PN16504 and, in Leybold documents, 9027900000. If the number on your old filament, in your manual and on your last order do not match, they are still the same part. Two things end a filament's life: gradual evaporation of the emitting surface over running hours, and sudden oxidation when air reaches it hot — a burst test piece, a hose pulled off in test mode, a roughing pump that loses seal. The first shows as a calibration factor that climbs month after month; the second kills it in one event. Handle with clean gloves only — fingerprints carbonise and shorten life — and recalibrate against a calibrated leak after fitting. Most of these cells hold two filaments, one in service and one on standby; if the controller has already switched to the standby, order two, because the standby is what is keeping you running.