PUMPING DOWN THE SPELEEM
Pumpdown is made through the fast entry lock, using the primary pump and the small turbo V70. At regime and during bake-out the main (MCH) and the prep chamber (PCH) are pumped using the big turbo in MCH. Here's the procedre to follow:
Check that the fast entry lock and MCH-PCH valves are open; the MCH-MCH turbo VAT valve must be closed;
Check that the V70 venting valve is closed. Then start the primary pump (the Vacuumbrand MV2 membrane pump); When the pirani gauge indicates 100 mbar, start the Varian V70 turbo pump. When the V-70 is in Normal operation, the controller indicates 75kHz, 22 W.
Start the MCH dry pump (Pfeiffer) and the MCH turbo (controller is labeled TCM 1601). Wait until the operation parameters are reached (660 Hz - 14 W).
When the airlock pirani shows UR-4 (this means the pressure is less than 10-3 mbar) open to the MCH turbo.
10 minutes after the two turbos are in normal operation, set the MCH ion gauge emission current to 0.3 mA (press F → Emis Ma). The MCH ion gauge can now be switched ON safely.
|
LEAK CHECK
When the MCH pressure is in the 10-7 range the QMS can be switched on and the leak-check performed. Run Programs/spectra/RGA on PnanoX. Then switch on filament one. REMEMBER: Only if the total pressure is less than 10-6 torr, the multiplier can be switched on. If so, switch on the multiplier, select the leak check mode and search for leaks.
|
|
