Question

. Your boss asks you to construct a gas ions source. You need to purchase a vacuum pump capable of achieving a vacuum of at least 4x10-7 torr and handling a gas load. Give the type of pump that you will purchase and justify your choice?

Answer 1

Turbomolecular Pumps (Dry, Kinetic Transfer)

Turbomolecular pumps works by transferring kinetic energy to gas molecules using high speed rotating, angled blades that propel the gas at high speeds. The blade tip speed is typically 250 -300 m/s. By transferring momentum from the rotating blades to the gas, they provide a greater probability of molecules moving towards the outlet. They can provide low pressures and have low transfer rates. A typical ultimate pressure of less than 7.5 x 10-11 Torr can be achieved. It has a pumping speed range of 50 – 5000 l/s.