Procedures And Additional Information; Cold Start Procedure; Degassing Filament Procedure; Normal Operation - Gamma Vacuum TSP User Manual

Procedures and Additional Information

Cold Start Procedure

This procedure is used when the pump is started after exposure to any pressure above 3.3 Pa (including
atmospheric pressure).
1. Check to see that the ion pump power supply and TSP Control are properly connected and that the
system is tightly sealed.
2. Begin the roughing procedure for the system.
3. Perform the Degassing Filament Procedure.
4. Start the ion pump (if available).
5. The roughing valve can normally be closed when the ion pump has started. This is indicated by an ion
pump voltage of 2000V or greater.
NOTE: The titanium film that evaporates during Step 3 provides very high pumping speeds for certain gases.
This results is faster starting for the ion pump and faster pump down at higher pressures (down to 1E-6 Pa),
where ion pump speeds are slower.

Degassing Filament Procedure

New filaments or ones that have been up to air must be outgassed into the roughing system. The following
procedure forces the major gas load from the filaments out of the system. A slight release of gas occurs each
time a filament is cycled ON, which is quickly pumped away by the ion pump.
1. Rough the system to a pressure of 0.25 Pa or lower.
2. Initiate the degas procedure from the TSP Configuration Menu.

Normal Operation

The amount of sublimated titanium that is required during normal operation is a function of the gas load in the
system. In some applications, such as thin film deposition, considerable titanium is required. In others, such as
space simulation where the outgassing load is small, only an occasional layer of fresh titanium is required. The
requirements of each application are best learned by experience. Use the information in this subsection as a
guide.
NOTE: During operation the filament current should be set at 48 Amps for a 30-second cycle time. Current levels
lower than 47 Amps sublimate less titanium and current levels above 50 Amps tend to shorten filament life.
TSP & Remote TSP Controller Users Manual
18