FAQ - Frequently Asked Questions

Running the instrument while there is a vacuum leak will lead to problems such as reduced sensitivity, increased noise, and breakage of the ion gauge (vacuum gauge) filament.
For this reason, always carry out a vacuum leak check on restarting the instrument after it has been stopped.
A whole range of vacuum leaks can affect the MS, from large leaks that stop the rotary pump from functioning normally to small leaks that are no hindrance to the normal operation of the triple inlet turbo molecular pump. These vacuum leaks develop from very small problems.
There are always O-rings fitted on parts with connections, such as the probe holder, between the lens system door and its housing, as well as the adjacent parts of the orifice. By making close contact with both sides at connections, these O-rings maintain the vacuum inside the housing by preventing vacuum leaks. If dirt adheres to an O-ring, or if you forget to fit an O-ring, a vacuum leak will occur.
When you stop the instrument and carry out maintenance work with the vacuum applied (cleaning of the lens system, replacement of the DL, replacement of the orifice), observe the following points in order to prevent vacuum leaks.

 

Cautions for preventing vacuum leaks
• Do NOT damage the seal faces.
• Do NOT forget to fit O-rings.
• Fit O-rings correctly.
• Remove any dirt that adheres to O-rings.
• Remove dirt on the faces with which the O-ring makes close contact (seal faces).

 

In the following circumstances, the rotary pump and triple inlet turbo molecular pump are not operating normally.
• The exhaust noise of the rotary pump continues for several minutes.
• The triple inlet turbo molecular pump started, but after the elapse of around 10 minutes the power to the vacuum system went OFF automatically.
In these cases it is probable that there is a vacuum leak or that the vacuum pump is abnormal. After the vacuum housing has leaked to atmospheric pressure, check the probe holder, lens system door, DL and orifice in accordance with "Cautions for preventing vacuum leaks" described previously.
If it is thought that a vacuum leak has occurred for reasons other than those described above, contact your Shimadzu representative.
NOTE: If the pressure is high, focus your attention on the locations subjected to maintenance.