Pfeiffer / Adixen ASM leak detectors: which 3G analyzer cell filament do I need, and why do they keep failing?

For the 3G analyzer cell used in ASM 310, ASM 340, ASM 380 and ASM 390, the filament part numbers you will see are 129108S and 114864S. The ASM 142 / 182 / 192 generation uses a different cell and takes 053146 (also listed as 2000052200). Getting this pair right is most of the ordering problem — the cells are not interchangeable even though both are called an ion source filament.

Filaments are a consumable, but the rate is not fixed. An instrument that is opened to atmosphere often, or that sniffs in a dusty plant, burns them far faster than one on a clean vacuum bench. Oxygen exposure while hot is the main killer: every time the cell sees air with the filament still energised, the emitting surface loses a little more.

What we see on the instruments we open: a large share of filaments sent to us as failed are not burnt through at all. The wire is intact and the real problem is elsewhere — a leaking elastomer seal in the analyser chamber raising the background, or a contaminated cell. That is why we ask for the symptom and not just the part number. A machine that will not zero its background does not always need a filament, and we would rather tell you that than sell you one.

On genuine versus compatible: we supply both and we say which is which in the quotation. The compatible filaments we stock are yttria-coated iridium, which is the same emitting chemistry the original uses; what differs is the supply channel and the price, not the coating. We do not describe a compatible part as OEM.

Send us the instrument model as it appears on the nameplate (ASM 340, ASM 340 D and ASM 340 W are different builds), the analyser cell generation if you know it, and one line on the symptom — background will not come down, sensitivity has dropped, or the filament is confirmed open-circuit. We confirm the part against your build before quoting.