Hi there. i have gone through most of the articles published, regarding Deacon process, by Herbert Over group and found it quite interesting. But i have a few question. It would be a great favour from you side, to answer these technical/scientific questions.
Thanks.
1. Does the chlorine sticking to the chamber walls, desorb with time or it forms certain salts by reacting to the chamber wall?
2. Do you expose mass spec and cold cathode p.guage to HCl/Cl2. etc.
3. Does the exposure of HCl to the Cold cathode pressure guage and mass spec, effects their effeciency?
4. How often do you bake out the system that includes mass spectrometer, ion pump and turbo pump, after exposing the it to HCL/Cl2.
5. What is the dosage pressure range of HCl during your experiments?
6. Did you come across a problem, while dosing the HCl through a stainless steel gas dosing lines?
7. what type of gaskets to you use, to avoid any reaction?
8. Do you use copper gaskets/ferrols etc?
Hi Asad
1.Cl can stick on the UHV chamber wall. However in a UHV system TiOx sublimation pump normally coats the UHV wall a thin layer of TiO2. Which kind of protects the wall.
2. a degree of HCL exposure would corrode the sensor/filament. flood the chamber with N2 as quick as possible and pump down again for an out gassing. Very small degree of HCL, for example, shown as e-8 in Quadrupole mass analyzer wouldn't be too bad.
3.Yes, deteriorate the filament most. Up to E-5 mbar it can also deteriorate the ionizer.
4.I have no experience however I would do a bake after exposing to HCL every time. Hard to get HCL out if you aim for e-10 UHV.
5.Not sure however please go with leak valve e-10 Torr L/S.
6.How about cold trap the gas line. and also purge it immediately after use.
7. Viton might hel, I won't go with copper.
8. Na...
The dose you plan to expose is also critical.
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